Organismal Biology

Observations and descriptions

• Scientific method
• Observations -> Questions -> Hypothesis -> Prediction -> test
• Requires verifiable observations, repeatable experimental results

• Definition ala Darwin: Descent with modification
• individuals don't adapt but a population does
• change on a generational basis
• evolution of a species is driven by Natural Selection
• It is not directed
• does not create new traits but works with traits already in the population
• need heritable traits
• the environment can play a big role in evolution

• The process in which individuals inherited traits allows it to reproduce at a higher rate (greater fitness) in a given environment relative to other members of its species.
• Maximization of reproductive output

• Similarity resulting from common ancestry reflects the evolutionary history of the species (Example: nucleic acids as genetic information)
• Sometimes vestigial structures exist because of common ancestry but are no longer in use (pelvic girdles in whales, appendix in humans)

given ancestry we can create trees, we group on similar homologous structure

• Populations adapt to the specific environmental conditions in which they reside. Unrelated species residing in similar environments can evolve superficially similar adaptions
• Example wings on birds and bats

a segment of DNA. can have multiple alleles

Small differences at the DNA level can be as small as 1 nucleotide

the physical location of the gene on the genome

heritable feature that varies between individuals

a varient for a character

• Mendel's model of inheritance
• If 2 alleles differ, the dominant allele is fully expressed while the recessive allele has no noticeable effect

• Mendel's model of inheritance
• If 2 alleles differ, the trait is a mixture of the two alleles

• Mendel's model of inheritance
• the 2 alleles for each character segregate during gamete production

the combination of alleles an individual has (PP,pp,Pp)

What you can see, i.e. the expressed trait

the additive effect of two or more genes

• given allele frequency p(A) and q(a)
• 1=p^2 + 2pq + q^2
• p^2 = frequency of homozygous AA
• q^2 = frequency of homozygous aa
• 2pq = frequency of heterozygous Aa
• Assume optimal model
• Deviations from Hardy-Weinberg equilibrium can be easily assessed using a χ2 (Chi-square) test

• measure of Gene variability
• the average number of loci that are heterzygous
• AA, Bb, Cc, dd, EE => 2/5 = 0.4

• measure of gene variability
• the average number of of heterozygous nucleotide starts

• Mutations are always occurring.
• Mutations can be deleterious, neutral or advantageous. – deleterious >> neutral >> advantageous
• single base pair mutations
• insertion and deletions (indels).
• Chromosomal – Inversions – Translocations – Duplications/deletions – Nondisjunction

• In addition to new mutations, a population’s gene pool will also change do to:
• Migration (gene flow)
• Random genetic drift
• Natural selection
• Non-random mating

• Gene flow via the migration can introduce new variants into a population. – Eg. Insecticide (DDT) resistance in mosquito (Culex pipiens).
• Gene flow across individuals from different populations continually mixes gene pools
• – Homogenizes the variation across populations.
• – Prevents genetic divergence across populations.

• the variation across the geographic range of a species. Could be either due to natural selection (adaption) or by chance
• Key Points:
• • Most significant in small populations.
• • Responsible for fluctuations in allele frequency.
• • Eventually lead to the loss of variation.
• • Can cause deleterious alleles to become fixed.

• When species move into new areas, only a few individuals actually colonize (i.e. little variation).
• Genetic Drift

• • Directional – selection for one extreme phenotype
• • Disruptive – selection for both extreme phenotypes
• • Stabilizing – selection against both extreme phenotypes

• Heterozygote has higher fitness
• Sickle-cell anemia is a recessive disorder that transforms red blood cells into a “sickle”.
• --– Heterozygotes are protected again some malaria symptoms.

• Fitness of a genotype dependent on its frequency in the population.
• Relative fitness is higher at lower frequencies.

• A species is a group of individuals that can successfully interbreed in nature and produce viable and fertile offspring.
• According to this definition you would expect:
• – gene flow (mating) within a species
• – no gene flow (mating) between species
• Reproductive isolation is the barrier that keeps species apart.
• Prevents the formation of species hybrids in nature (ie. Gene flow).

• BEFORE fertilization: Prezygotic barrier (or Prezygotic isolation)
• AFTER fertilization: Postzygotic barrier (or Postzygotic isolation)

• Prezygotic barrier
• Species occupy different habitats, therefore they do not have even the opportunity to mate.
• eg. insects using different plants in the same area.

• Prezygotic barrier
• If species are reproductively active at different times, then they can’t hybridize.
• eg. flowering time

• Prezygotic barrier
• Differences in courtship rituals will prevent hybridization.
• – eg. Blue-footed boobies

• Prezygotic barrier
• Mechanical differences prevent the successful mating.
• – eg. Bradybaena snails

• Prezygotic barrier
• Differences in egg and/or sperm prevent fertilization.
• – eg. sea urchins

• Postzygotic barrier
• Fertilization occurs, but hybrid dies (in development or in the environment).
• – eg. Ensatina salamanders

• Postzygotic barrier
• Hybrid individual are sterile.
• – eg. Drosophila mojavensis & D. arizonae.

• Postzygotic barrier
• Hybrids are viable and fertile, but have a reduced or no mating success.
• – eg. Rice strains
• – eg. Lake white fish (Coregonus clupeaformis)

• Individuals with a similar morphology are a single species.
• Works on sexual and asexual species, but it can be a subjective.
• – Which morphological character is most important?

• The ecology of individuals defines the species.
• – eg. food, shelter, physiology, etc...
• Works on sexual and asexual species, but need to have a very clear understanding of the ecology of organisms.

• Differences at the genetic level defines a species.
• Works on sexual and asexual species, but need to define the degree of difference allowed and still be a single species.

• Speciation ultimately occurs when two gene pools become isolated.
• Isolating mechanism describes how two species are
• prevented from coming back together.
• The initial separation can occur in:
• – allopatry
• – sympatry

• Gene flow is prevented do to geographic features.
• – eg. river, mountain, island . . .
• After the initial isolation of the two gene pools, divergence can occur via:
• – Random genetic drift can occur via:
• – Natural selection (adaptation, sexual, ....)
• – Random genetic drift – Both

• Speciation occurring between population living in the same geographic area.
• How can you have divergence in gene pools if individuals have the possibility to mate?
• – The force(s) splitting gene pools must be stronger than of the homogenizing effect of gene flow.

• Shifts in resource utilization could be a strong.
• Apple maggot (Rhagoletis pomonella)

• Mate preference can also drive gene pools apart.
• Given variation in morphological or behavior characters and variation in mate choice, disruptive selection could occur.
• Lake Victoria Fish

• Polyploidy is the occurrence of extra chromosome do to an error in cell division.
• Not very common in animals, but very common in plants (over 80% of extant species).
• In plants you can have: – autopolyploids – allopolyploids

is when the extra set(s) of chromosomes originate from a single species.

• is when the extra set(s) of chromosomes originate from different species.
• common in crop plants

• Hybrid zones are regions were contact between two different species produces hybrid individuals.
• Within a hybrid zone alleles from both species can be found in individuals sampled
• There are 3 possible scenarios for a hybrid zone
• 1) Reinforcement (gets narrow or goes away)
• 2) Fusion (the two species become one)
• 3) Stability (Persists over time)

• The hypothesis for the origins of life on Earth states that life came about through the following steps:
• 1. Abiotic synthesis of small organic molecules
• 2. Joining of these small molecules into macromolecules
• 3. Packaging of molecules into protocells
• 4. Origin of self-replicating molecules (RNA was likely the first genetic material.)

Protocells are membrane structures that can isolate its content from the external environment.

are cells that lives within another cell

• proposes that mitochondria and living within larger host cells
• plastids (eg. chloroplasts) were formerly small prokaryotes living within larger host cells

• The beginning of the Cambrian (535-525 mya) is marked by the sudden appearance of fossils resembling modern animal phyla.
• A few animal phyla appear even earlier: sponges, cnidarians, and molluscs.
• The Cambrian explosion provides the first evidence of predator-prey interactions.

• The largest of all extinctions.
• 251 mya
• 96% of all marine species extinct!!!
• Caused by extremely high volcanic activity that caused global climate change.
• – Temperature increase by 6 °C. – Ocean anoxia

• 65.5 mya
• Extinction of almost all dinosaurs.
• Likely caused by a large asteroid (10 km diameter)

• occur when a large number of species evolve in a relative short period of time.
• – Following mass extinctions – Colonization events – Evolution of key innovations

• Cladistics groups organisms by common descent.
• A clade is a group of species that includes an ancestral species and all its descendants.
• Clades can be nested into larger clades.

consists of the ancestor species and all its descendants

consists of an ancestral species and some, but not all, of the descendants.

consists of various species with different ancestors

assumes that the tree that requires the fewest evolutionary events (appearances of shared derived characters) is the most likely.

• Mutations have a probability of occurring every generation.
• As long as the rate of mutation is constant, mutations will accumulate at a constant rate.
• We can use this clock-like manner of molecular evolution as a molecular clock.

• The majority of mutations are deleterious, therefore will be removed from the population
• Advantageous mutations will quickly fixed therefore will not be seen.
• Hence the majority of mutations (variation) in a population will be neutral

• Five kingdoms were recognized: Monera (prokaryotes), Protista, Plantae, Fungi, and Animalia.
• Three-domain system has been adopted: Bacteria, Archaea, and Eukarya

• is the movement of genes from one genome to another.
• – transposable elements – virus – hybridization

• Bacterial cell walls contain peptidoglycan.
• – sugar polymers cross-linked by polypeptides.

• The Gram stain is used to classify bacteria by cell wall
• composition.
• For Bacteria: – Gram-positive bacteria have simpler walls with a large amount of peptidoglycan.
• – Gram-negative bacteria have less peptidoglycan and an outer membrane that can be toxic.

• • Identification of bacterial species.
• • In medicine, it can help direct a treatment plan.
• • Many antibiotics target peptidoglycan and damage bacterial cell walls.
• • Gram-negative bacteria are more likely to be antibiotic resistant.

• • Many bacteria have the ability to move toward or away from a stimulus (taxis).
• • Chemotaxis is the movement toward or away from a chemical stimulus.
• • Most motile bacteria propel themselves by flagella.

is the movement toward or away from a chemical stimulus.

• Prokaryotes have a great amount of genetic variation.
• Three factors contribute to this genetic diversity: – Rapid reproduction – Mutation – Genetic recombination

• Combining of DNA from two sources.
• Contributes to bacterial diversity.
• DNA from different individuals can be brought together by different processes.
• When the exchange is between different species is called horizontal gene transfer.

The uptake of DNA from the environment.

The movement of genes between bacteria by phages (viruses that infect bacteria).

• The transfer of genetic material between prokaryotic cells.
• The DNA transfer is one way.
• A donor cell attaches to a recipient by a pilus, pulls it closer, and transfers DNA.
• A piece of DNA called the (Fertility Factor) F factor is required for the production of pili.

• Obligate aerobes require O2 for cellular respiration.
• Obligate anaerobes are poisoned by O2 and use fermentation or anaerobic respiration.
• Facultative anaerobes can survive with or without O2.

• Prokaryotes can metabolize nitrogen in a variety of ways.
• – Nitrogen is essential for amino acids and nucleic acids.
• In nitrogen fixation, some prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3)

Surface-coating colonies

• Archaea
• live in highly saline environments.

• Archaea
• thrive in very hot environments.

• Archaea
• live in swamps and marshes and produce methane as a waste product.
• Methanogens are strict anaerobes and are poisoned by O2.
• Very important for sewage treatment.

• Diverse nutritional types.
• – Pathogens to beneficial types.
• • Proteobacteria
• • Chlamydias
• • Spirochetes
• • Cyanobacteria
• • Gram-positive bacteria

• [Bacteria]
• These gram-negative bacteria include photoautotrophs, chemoautotrophs, and heterotrophs.
• Some are anaerobic, and others aerobic.

• [Bacteria]
• These bacteria are parasites that live within animal cells.
• Chlamydia trachomatis causes blindness and nongonococcal urethritis by sexual transmission

• [Bacteria]
• These bacteria are helical heterotrophs.
• Some are parasites, including Treponema pallidum, which causes syphilis, and Borrelia burgdorferi, which causes Lyme disease.

• [Bacteria]
• These are photoautotrophs that generate O2.
• Plant chloroplasts likely evolved from cyanobacteria by the process of endosymbiosis.

• [Bacteria]
• • Gram-positive bacteria include
• – Actinomycetes, which decompose soil
• – Bacillus anthracis, the cause of anthrax
• – Clostridium botulinum, the cause of botulism
• – Some Staphylococcus and Streptococcus, which can be pathogenic
• – Mycoplasms, the smallest known cells

function as decomposers, breaking down dead organisms and waste products.

harms but does not kill its host.

Parasites that cause disease

• Eukaryotes – cells have organelles and are more complex than prokaryotic cells.
• Most protists are unicellular, but there are some colonial and multicellular species.
• Some reproduce asexually while others sexually.
• Vast amounts of structural and functional diversity
• – more than other group of eukaryotes (plants, fungi & animals).
• Very complex cells – organelles can perform multiple biological functions

contain chloroplasts

absorb organic molecules or ingest larger food particles

photosynthesis and heterotrophic nutrition

• One organism engulfing another and creating a stable and dependent relationship
• Mitochondria evolved by endosymbiosis of an aerobic prokaryote (alpha proteobacteria).
• Plastids evolved by endosymbiosis of a photosynthetic cyanobacterium

• The plastid-bearing lineage of protists evolved into red and green algae
• The DNA of plastid genes in red algae and green algae closely resemble the DNA of cyanobacteria
• On several occasions during eukaryotic evolution, red and green algae where themselves engulfed by another heterotrophic eukaryote (secondary endosymbiosis)

• Protists
• The clade Excavata is characterized by its cytoskeleton
• Some members have a feeding groove.
• • Diplomonads
• • Parabasalids
• • Euglenozoans
• --– Kinetoplastids
• • Trypanosomes
• --– Euglenids

• [Excavata] protists
• Lack plastids
• Have modified mitochondria
• Diplomonads – Derive energy from anaerobic biochemical pathways. Have two equal-sized nuclei and multiple flagella Are often parasites, for example, Giardia intestinalis
• Parabasalids – Include Trichomonas vaginalis, the pathogen that causes “yeast” infections in human females.

• [Excavata: Euglenozoans] protists
• A single mitochondrion
• This group includes Trypanosoma, which causes sleeping sickness and Chagas in humans.

• [Excavata] protists
• Trypanosomes evade immune responses by switching
• surface proteins.
• A cell produces millions of copies of a single protein.
• The new generation produces millions of copies of a different protein.
• These frequent changes prevent the host from developing immunity.

• [Excavata] protists
• Have one or two flagella that emerge from a pocket at one end of the cell.
• Mixotrophs

• Data suggest that the clade Chromalveolata is monophyletic and originated by a secondary endosymbiosis event.
• The proposed endosymbiont is a red algae.
• • Alveolates
• –-- Dinoflagellates
• --– Apicomplexans
• • Plasmodium
• --– Ciliates
• • Stramenopiles
• --– Diatoms
• --– Brown Algae
• --– Oomycetes

• [Chromalveolata] protists
• Alveolata have membrane-bounded sacs (alveoli) just under the plasma membrane. – function unknown
• The alveolates include:
• • Dinoflagellates
• • Apicomplexans
• • Ciliates

• [[Chromalveolata] Alveolata]
• Two flagella and each cell is reinforced by cellulose plates.
• They are abundant components of both marine and freshwater phytoplankton.
• Toxic “red tides” are caused by dinoflagellate blooms

• [[Chromalveolata] Alveolata]
• Parasites of animals, and some cause serious human
• diseases.
• One end, the apex, contains a complex of organelles specialized for penetrating host cells and tissues.
• Most have sexual and asexual stages that require two or more different host species for completion.
• An apicomplexan Plasmodium is one of the parasite that causes malaria.

• [[Chromalveolata] Alveolata]
• Use of cilia to move and feed.
• They have large macronuclei and small micronuclei.
• Genetic variation results from conjugation, in which two individuals exchange haploid micronuclei
• – separate from reproduction (binary fission).

• [Chromalveolata]
• Most have a “hairy” flagellum paired with a “smooth”
• flagellum
• Include important phototrophs as well as several clades of heterotrophs.
• Diatoms, Brown Algae, Oomycetes

• [[Chromalveolata] Stramenopiles]
• Diatoms are unicellular algae with a unique two-part, glass-like wall of hydrated silica.
• Diatoms usually reproduce asexually, and occasionally sexually
• Major component of phytoplankton and are highly diverse.
• After population bloom, dead individuals fall to the ocean floor undecomposed. – carbon sink

• [[Chromalveolata] Stramenopiles]
• Brown algae are the largest and most complex algae. All are multicellular, and most are marine.– eg. kelp
• Complex multicellular anatomy. – The algal body is plantlike but lacks true roots, stems, and leaves and is called a thallus.
• Brown algae reproduce through a process of alternation of generations. – alternation of multicellular haploid and diploid forms.
• Heteromorphic generations are structurally different, while isomorphic generations look similar.

• [[Chromalveolata] Stramenopiles]
• Water molds, white rusts, and downy mildews.
• Most oomycetes are decomposers or parasites.
• Their ecological impact can be great, as in potato blight caused by Phytophthora infestans.

• Many move using pseudopodia – extensions of the cytoplasm that anchor itself and is used to pull the organism.
• Many amoebas are included in this group.
• Radiolarians, Foraminiferans, Cercozoans

• [Rhizaria]
• Mostly marine
• Symmetrical internal skeleton usually made of silica
• Use pseudopodia to engulf microorganisms
• The pseudopodia of radiolarians radiate from the central body

• [Rhizaria]
• Porous multichambered shells called tests
• Pseudopodia extend through the pores in the test
• Many forams have endosymbiotic algae.

• [Rhizaria]
• Most amoeboid and flagellated protists with threadlike
• pseudopodia.
• They are common in marine, freshwater, and soil ecosystems
• Most are heteroptrophs, including parasites and predators

• Plastid derived from a cyanobacterial endosymbiont.
• This supergroup that includes red algae, green algae, and land plants
• • Red algae
• • Green algae – Charophytes – Chlorophytes

• [Archaeplastida]
• Reddish in color due to an accessory pigment
• (phycoerythrin).
• Red algae are usually multicellular; the largest are seaweeds

• [Archaeplastida]
• Contain green chloroplasts.
• The two main groups are chlorophytes and charophytes

• [[Archaeplastida] Green Algae]
• Fresh water and marine.
• Symbionts in lichens
• Large size achieved by:
• 1. Colonies of individual cells.
• 2. Formation of true multicellular bodies by cell division and differentiation.
• 3. Repeated division of nuclei with no cytoplasmic division.

• [[Archaeplastida] Green Algae]
• Charophytes are most closely related to land plants.

• Amoebozoans include: – Slime molds – Gymnamoebas – Entamoebas
• Opisthokonts: Fungi, animals & other protists

• [[Unikonta] Amoebozoans]
• Plasmodial slime molds form large multinucleated masses and webs called plasmodium.
• Cytoplasm streams within the plasmodium.
• Cellular slime molds form multicellular aggregates in which cells are separated by their membranes.
• Cells feed individually, but can aggregate to form a fruiting body

• Land plants evolved around 500 MYA from ancestors of green algae.
• Very diverse (290,000 species).
• Ecologically very important.– 50% of global photosynthesis
• Charophytes are the closest relatives of land plants.

• Sporopollenin, a layer of a durable polymer, prevents exposed zygotes from drying out (also found in charophytes).
• Many benefits in moving onto land: – unfiltered sun – more plentiful CO2 – nutrient-rich soil – few herbivores or pathogens.
• Also several problems to deal with during the colonization of land:– desiccation – structural support

• 1) Alternation of generations and multicellular, dependent embryos.
• 2) Walled spores produced in sporangia.
• 3) Multicellular gametangia.
• 4) Apical meristems

• Plants alternate between two multicellular stages, a
• reproductive cycle called alternation of generations.
• The gametophyte is haploid and produces haploid gametes by mitosis.
• Fusion of the gametes gives rise to the diploid sporophyte,which produces haploid spores by meiosis.

• The diploid embryo is retained within the tissue of the female gametophyte.
• Nutrients are transferred from parent to embryo through placental transfer cells.
• Land plants are called embryophytes.

• The sporophyte produces spores in organs called sporangia
• Diploid cells called sporocytes undergo meiosis to generate haploid spores.
• Spore walls contain sporopollenin, which makes them resistant to harsh environments.

Gametes are produced within organs called gametangia

• Plants sustain continual growth in their apical meristems.
• Cells from the apical meristems differentiate into various tissues.

• Non vascular land plants
• Bryophytes are represented today by three phyla of small herbaceous (nonwoody) plants.
• – Liverworts, phylum Hepatophyta
• – Hornworts, phylum Anthocerophyta
• – Mosses, phylum Bryophyta
• Gametophytes are larger and longer-living than sporophytes
• A spore germinates into a gametophyte composed of a protonema and gamete-producing gametophore.

• Mature gametophytes produce flagellated sperm in antheridia and an egg in each archegonium
• Sperm swim through a film of water to reach and fertilize the egg

• Sporophytes grow out of archegonia, and are the smallest and simplest sporophytes of all extant plant groups.
• A sporophyte consists of a foot, a seta (stalk), and a through a peristome. sporangium, also called a capsule, which discharges spores through a peristome.

are branched filaments that absorbs nutrients.

is the gamete-producing structures stemming from the protonema.

anchor gametophytes to substrate

• Vascular plants began to diversify during the Devonian and Carboniferous periods (425 MYA).
• Vascular tissue allowed these plants to grow tall

• Life cycles with dominant sporophytes
• Vascular tissues called xylem and phloem.
• Well-developed roots and leaves.

• Seedless vascular plants have flagellated sperm.
• Sporophytes are the larger generation.
• The gametophytes are tiny plants that grow on or below the soil surface

• conducts most of the water and minerals and includes dead cells called tracheids.
• – strengthened by lignin and provide structural support.

consists of living cells and distributes sugars, amino acids, and other organic products

• are organs that anchor vascular plants.
• They enable vascular plants to absorb water and nutrients from the soil.
• Roots may have evolved from subterranean stems

• are organs that increase the surface area of vascular plants
• – Increase the amount of solar energy that is used for photosynthesis.

• Most seedless vascular plants are homosporous, producing one type of spore that develops into a bisexual gametophyte
• All seed plants and some seedless vascular plants are heterosporous
• – megaspores ⎝ female gametophytes
• – microspores ⎝ male gametophytes

• The evolution of seeds allowed for the further colonization of terrestrial habitats.
• Seeds consists of an embryo and nutrients surrounded by a protective coat.
• Can remain dormant for days to years, until conditions are favorable for germination.
• Can be transported long distances by wind or animals

• • Seeds
• • Reduced gametophytes
• • Heterospory
• • Ovules
• • Pollen

• Develop within the walls of spores.
• Greatly reduced, microscopic.
• Protected, housed within tissues of the parent sporophyte.
• Dependent on sporophyte for nutrition and protection

• Megasporangia produce megaspores that give rise to female gametophytes.
• Microsporangia produce microspores that give rise to male gametophytes.

• An ovule consists of:
• – megasporangium – megaspore – one or more protective integuments

develops from the microspore housed within the microsporangium

• Gymnosperms means “naked seeds”.
• Vascular seed plants
• appear about 350 MYA. Extant gymnosperms appear about 300 MYA.
• Dominated Mesozoic (251–65 MYA) forest.
• Adapter to drier conditions.
• Dominated by sporophyte.
• Seeds develop from fertilized ovules
• Sperm transferred via pollen
• Four extant phyla:
• – Cycadophyta
• – Gingkophyta
• – Gnetophyta
• – Coniferophyta

• Gymnosperms
• Vascular seed plants
• Large cones and palmlike leaves.
• Very abundant during Mesozoic.
• Flagellated sperm.

• Gymnosperms
• Vascular seed plants
• This phylum consists of a single living species, Ginkgo
• biloba.
• Flagellated sperm

• Gymnosperms
• Vascular seed plants
• Tropical to desert species

• Gymnosperms
• Vascular seed plants
• ~600 species
• Evergreens

• Vascular seedless plants
• Club mosses, spike mosses & quilworts

• Vascular seedless plants
• Ferns and horsetails

• Vascular seed plants
• Flowering plants
• Have Flowers, Fruit
• The most widespread and diverse of all extant plants
• A single phylum, Anthophyta

• Specialized for sexual reproduction.
• Pollinated by insects, mammals or wind.
• A flower is a specialized shoot with up to four types of modified leaves.
• • Stamens = produce pollen
• --– filament (stalk)
• --– anther is the site of pollen production
• • Carpels = produce ovules
• --- stigma is where pollen attache
• --- style
• --- ovary where ovules are housed
• • Petals = brightly colored and attract pollinators
• • Sepals = enclose the flower.

• A fruit typically consists of a mature ovary.
• Fruits protect seeds and aid in their dispersal.
• Mature fruits can be either fleshy or dry.

• The flower is the sporophyte.
• Male gametophytes are within pollen grains produced by the microsporangia of anthers.
• The female gametophyte, or embryo sac, develops within an ovule.

• Less derived and include the flowering plants belonging to the oldest lineages
• • Amborella (egg formation resembles gymnosperms)
• • Water lilies
• • Star anise

Magnoliids include magnolias, laurels, and black pepper plants

• Amoebozoans
• – Plasmodial slime molds
• – Cellular slime molds
• Opisthokonts
• – Fungi, animals & other protists

• Fungi are heterotrophs.
• Use enzymes to break down complex molecules into smaller organic compounds.
• These digestive enzymes are very versatile, which contributes to fungi’s ecological success.

• The most common body structures are multicellular filaments and single cells (yeasts).
• Some species grow as either filaments or yeasts; others grow as both.
• The morphology of multicellular fungi enhances their ability to absorb nutrients
• Fungi consist of mycelia, networks of branched hyphae adapted for absorption
• A mycelium’s structure maximizes its surface area-to-volume ratio
• Fungal cell walls contain chitin.

Most fungi have hyphae divided into cells by septa, with pores allowing cell-to-cell movement of organelles.

• have a mutualistic relationship with plants
• These fungi have specialized hyphae called haustoria that allow them to penetrate the tissues of their host

• lack septa
• Have a continuous cytoplasmic mass with hundreds or thousands of nuclei

form sheaths of hyphae over a root and also grow into the extracellular spaces of the root cortex.

extend hyphae through the cell walls of root cells and into tubes formed by invagination of the root cell membrane

• Fungal nuclei are normally haploid, with the exception of transient diploid stages formed during the sexual life cycles.
• Sexual reproduction requires the fusion of hyphae from different mating types.
• Fungi use sexual signaling molecules (pheromones) to communicate their mating type.
• Under the appropriate conditions when cells from different mating types meet they will fuse

• is the union of cytoplasm from two parent mycelia.
• – NOT the fusion of the nuclei.

In most fungi, the haploid nuclei from each parent do not fuse right away; they coexist in the mycelium, called a heterokaryon.

In some fungi, the haploid nuclei pair off two to a cell; such a mycelium is said to be dikaryotic.

• During karyogamy, the haploid nuclei fuse, producing diploid cells. – a long time can pass until fusion occurs.
• The diploid phase is short-lived and undergoes meiosis, producing haploid spores.
• The paired processes of karyogamy and meiosis produce genetic variation.

• Fungi, animals, and their protistan relatives form the opisthokonts clade.
• Fungi are most closely related to unicellular nucleariids.
• Oldest fossils of fungi are only about 460 million years old.
• Molecular analyses suggests the fungal/animal split occurred 1 BYA

• Fungi
• (phylum Chytridiomycota) are found in freshwater
• and terrestrial habitats.
• They can be decomposers, parasites, or mutualists.
• Molecular evidence supports the hypothesis that chytrids diverged early in fungal evolution.
• Chytrids are unique among fungi in having flagellated spores, called zoospores
• The chytrid Batrachochytrium dendrobatidis might be the cause of the recent decline in amphibians worldwide

• Fungi
• (phylum Zygomycota) exhibit great diversity of life histories.
• They include fast-growing molds, parasites, and commensal symbionts.
• The zygomycetes are named for their sexually produced zygosporangia.
• Zygosporangia are the site of karyogamy and then meiosis.
• Zygosporangia, which are resistant to freezing and drying, can survive unfavorable conditions.
• Some zygomycetes, such as Pilobolus, can aim their sporangia toward conditions associated with good food source

• Fungi
• (phylum Glomeromycota)
• Glomeromycetes form arbuscular mycorrhizae

• Fungi
• Ascomycetes (phylum Ascomycota) live in marine, freshwater, and terrestrial habitats
• Produce sexual spores in saclike asci contained in fruiting bodies called ascocarps.
• – sometimes called sac fungi
• From unicellular yeasts to elaborate cup fungi and morels
• Plant pathogens, decomposers, symbionts and predators
• Arthrobotrys is one of several species of fungi that are predatory.
• Ascomycetes reproduce asexually by enormous numbers of asexual spores called conidia.
• Conidia are not formed inside sporangia; they are produced asexually at the tips of specialized hyphae called conidiophores.

• Fungi
• (phylum Basidiomycota) include mushrooms,
• puffballs, and shelf fungi, mycorrhizae, and plant parasites.
• The phylum is defined by a clublike structure called a basidium, a transient diploid stage in the life cycle.
• – sometimes called club fungi
• Usually includes a long-lived dikaryotic mycelium.
• The mycelium reproduces sexually by producing elaborate fruiting bodies call basidiocarps.
• The numerous basidia in a basidiocarp are sources of sexual spores called basidiospores

• A lichen is a symbiotic association between a photosynthetic microorganism and a fungus.
• Millions of photosynthetic cells are held in a mass of fungal hyphae.
• The photosynthetic component is green algae or cyanobacteria.

Obtain energy from consuming organic matter

Groups of cells that have a common structure and/or function

The rapid cell division without cell growth that occurs after fertilization

Leads to formation of a multicellular blastule

A multicellular hollow formed after cleavage.  Will undergo gastrulation, and form a gastrula with different layers of embryonic tissue

Sexually immature and morphologically distinct from adult.

Larva undergoes metamorphosis, the reorganization of larval tissues into a juvenile.

Only animals have these (mostly).

• Regulate the development of body form.  Master regulators that give orientation to the embryo.  The genes are ordered in the
• order they are expressed from anterior to posterior

Multicellular Eukaryotes

• Multicellular bodies held together by structural
• proteins

Nervous and muscle tissue are a unique characteristic of animals

Most reproduce sexually.

Diploid stage is dominant.

• Choanoflagellates
• Sponges collar cell in coaocyte

Cambrian explosion (535-525mya) marks the early radiation of species.  

• Contributing Factors:
• ·     Evolution of predator/prey relationship
• ·     Evolution of defensive and offensive structures
• ·     Evolution of Hox genes
• ·     Changes in atmosphere composition

Diversity continues to increase.

Several mass extinction events

Transition to terrestrial habitats (460mya)

Vertebrates transition to land ~360mya

251-65.5mya

Coral reefs

Dinosaurs dominated terrestrial habitats

Mammals evolve

Angiosperms and insects diversify

A set of morphological and developmental traits used to categorize animals.  Involves symmetry, tissue development, and order of developmental steps.

Development of a central nervous system in the head.  A central location that controls body function.   Result is more active animals.

The Germ layer covering the embryo's surface

An intervening layer of tissues between Ectoderm and endoderm

Inner most germ layer, lines the developing digestive tube called the archentron

triploblastic animals that lack a body cavity (Flat worms)

Body cavity is derived from the mesoderm and endoderm.

Triploblastic animals that have a true coelom (earth worms)

• Animals have no front, back, left or right.
• Often sessile or planktonic animals

2 sided symmetry.  Have a dorsal (top), ventral (bottom), anterior (head), and posterior (tail).

• Cleavage is spiral and determinate (ultimate fate of cells is established early on).
• The splitting of solid masses of mesoderm forms a true coelom.
• The blastophore forms during gastrulation and connect the archentron to the exterior of the gastrula.  
• The blastophore will become the mouth.

• Cleavage is radial and indeterminate 
• The mesoderm buds from the wall of the archentron to form the coelom.  
• The blastophore will become the Anus.

A group whose members share key features

• Group metazoa
• Sponges
• Heterotrophic
• Sedentary
• Water is drawn through pores into a cavity called a spongocoel and out through the osculum.  
• Most are hermaphrodites

• One of the oldest phyla
• Both sessisle poly p and motile forms (free-swimming medusa)
• Simple diploblastic radial body plan
• Gastrovascular Cavity
• Classes: Hydrozoans, Scyphozoans, Cubozoans, Anthozoans
• Carnivores that use tentacles to capture prey that are armed with cnidocytes with a nematocyte "harpoon"

A sac with a central digestive compartment that functions as both mouth and anus

• Phylum: Cnidarian
• Mostly marine
• alternate between polyp and medussa forms

• Phylum: Cnidarian
• Jellies are most prevalent
• Medussa form is prevalent

• Phylum: Cnidarian
• Box Jellies and sea wasps
• highly toxic cnidocytes

• Phylum: Cnidarian
• Corals and sea anemones
• only polyp

• A clade
• Includes comb jellies
• diploblastic
• radial symmetry
• use cilia for locomotion

• Grade
• Some have feeding structures called lophophores
• others have a distinct developmental stage called the trophophore larva
• others have lost one or the other during evolution
• Phylums: Platyhelminthes, Rotifera, Ectoprocta, Braciopoda, Mollusca, Annelida

• Phylum
• Flatworms
• Triploblastic Acoelomates
• Are flattened dorsoventrally and have a gastrovascular cavity with 1 opening
• gas exchange occurs across the body surface
• Classes: Catenulida (chain worms) & Rhabditophans

• Phylum: Platyhelminthes
• Free living and parasitic
• Planarians: live in fresh water and prey on small animals.  Have light sensitive eye spots (not true eyes)
• Subgroups: Trematodes, and Tapeworms

• phylum
• Tiny animals that inhabit fresh water and ocean, and damp soil.
• Have an alimentary canal with a separate mouth and anus that lies within a fluid filled pseudocoelom
• Triploblastic

• phylum
• Like clams but with different shell orientation
• have a lophophore
• coelomates

• phylum
• Filter feeders
• sieve food out of water using lophophore lined with cilia
• marie species
• colonial

• phylum
• Includes snails, slugs, oysters, clams, squid, octopi etc
• most are marine, some terrestrial
• Coelomates
• Contain a muscular foot, visceral mass and mantle
• feed with rasp like radula
• separate sexes
• Classes: Polyplacophora, Gastropoda, Bivalvia, Cephalopoda

• phylum: Mollusca
• Chitins are oval shapped marine animals encased in an armor of 8 dorsal plates.  Use a foot like suction to hold on to the rock, and radula to scrape algae off it.

• phylum: Mollusca
• Majority 
• Snails and slugs
• Torsion which causes the animals anus to end up above its head

• phylum: Mollusca
• Marine
• clams, oysters, mussels, and scallops
• A shell divided into 2 halves drawn together by abductor muscles.
• Some have eyes and sensory tentacles along the edge of their mantle

• phylum: Mollusca
• Carnivores with beak-like jaws surrounded by tentacles
• closed circulatory system, well developed sense organs and complex brains.
• Squid, Octopi and nautiluses

• Phylum
• Bodies composed of fused rings
• Classes: Polychaeta, Olgiochaeta

• Phylum Annelida
• "many bristles"
• Have padlike parapodia that work as gills and aid in locomotion

• Phylum Annelida
• "few bristles"

• grade
• covered by a tough coat called a cuticle which is shed or molded through the process called ecdysis
• Phylums: Anthropoda and Nematoda

• grade Ecdysozoa
• Round worms found in everywhere
• Have an alimentary canal, pseudocoelom, no circulatory system, no segmented body
• C. Elgans

• grade Ecdysozoa
• 2/3 of extant species
• segmented hard exoskeleton and jointed appendages  little variation between segments
• Generally 3 sections: head, thorax and abdomen
• Have eyes, olfactory receptors and antennae that function in touch and smell
• Open circulatory system with hemolymph
• Evolution characterized by a decrease in the number of segments and increase in specialization
• Sub phyla: Chielicereta, Myriapoda, Hexapoda, Crustacea

• Major Phylum Anthoropoda
• Named for clawlike feeding appendages called chelicerae.  
• Horseshoe crabs, arachanids, ticks, mites and scorpions
• Cephalothorax with 6 pairs of appendages (Chelicerae, pedipalps, 4 walking leg sets)
• Gas exchange occurs via book lungs

• Major Phylum Anthoropoda
• Millipedes: eat leaves, 2 leg pairs per segment
• centipedes: eat decaying animals, 1 leg pair per segment

• Major Phylum Anthoropoda
• six legs
• Includes insects and relatives
• Tracheal tubes are used for gas exchange
• many undergo metamorphosis
• some undergo incomplete metamorphosis
• Key Innovations for success: Flight, gymnosperm adaption, angiosperm adaption
• Over 30 orders!

• phylum Heapods
• Beetles
• 2 pairs of wings (1 thick and strong, 1 for flying)
• Complete metamorphosis

• phylum Heapods
• Flies and mosquitoes
• 1 pair of wings and halteres (reduced second pair for balance)
• Complete metamorphosis

• phylum Heapods
• Bees, ants and wasps
• Social
• 2 pairs of wings
• Complete metamorphosis

• phylum Heapods
• Moths and butterflies
• 2 pairs of wings covered in scales
• Complete metamorphosis

• phylum Heapods
• Assassin bugs, kissing bugs (true bugs)
• 2 pairs of wings (1 leathery)
• Incomplete metamorphosis

• phylum Heapods
• grasshoppers and crickets
• 2 pairs of wings (1 leathery)
• large hind legs (hoppers)
• Incomplete metamorphosis

• Phylum
• Typically have branched appendages that are extensively specialized for feeding and locomotion
• smaller exchange gas through cuticle, others have gills
• Marine
• Classes: Isopods (6 legs), Decapods (5 pairs of appendages), Barnacles (mostly sessile), Copepods (food source for many filter feeders)

Unikonta

• Heterotrophs
• structures are muticellular filaments and single cells
• Consist of mycellia, and hyphae, and septa

• Fungi
• A collection of hyphae in a net like structure.
• Most of a fungus's life cycle is spent in this structure.

• Fungi
• Funcale cell walls containe chitin, divided into cells by septa

• Fungi
• pores allowing cell to cell movement of organelles

Have a continuous cytoplasmic mass with hundreds or thousands of nuclei

• Have a mutalistic relationship with plants
• Have specialized hyphae call haustoria that allow them to penetrate the tissues (cell walls not membranes) of their host.  resulting in an increase in surface to area which they interact and exchange nutrients.

Form sheaths of hyphae over a root and grow into the extracellular spaces of the root cortex

extend hyphae through cell walls of root cells and into tubes...

• Fungi
• The union of the cytoplasm from two parent mycellia.
• Fusion of two haploid cells to make an heterokaryotic cell (n+n)

• Fungi
• Fusion of haplois nuclei to make a zygote (2n).
• This step can take awhile to occur

• Fungi
• A cell where the haploid nuclei from each parent does not fuse right away they coexist in the mycellium
• Organism is technically diploid (n+n)

• In some fungi the haplois nuclei pair off two to a cell. 
• 1 cell with 2 haploid nuclei still unfused

After karyogaomy, the diploid zygote stage is short lived and undergoes meiosis producing haploid spores.

• Oldest fossils are ~460MYA
• Molecular analysis suggests that fungal animal split occured ~1BYA
• Fungi are among the earliest colonizers of land

• Fungi kingdom
• Fresh water and terrestrial habitats
• Unique among fungi in having flagellated spores called zoospores

• Fungi kingdom
• Include molds, parasites etc
• Named for their sexually produced zygosporangia (site of karyogamy and meiosis).
• Resistant to drying and freezing and can survive unfavorable conditions

• Fungi kingdom
• Form arbuscular mycorhizae

• Fungi kingdom
• All habitats
• PRoduce spores in sac like asci contained in fruiting bodies called ascocarps - sometimes called sac fungi
• From unicellular yeasts to elaborate cup fungi and morels
• Reproduce asexually by enormous numbers of asexual spores called condia which are not formed inside the sporangia

• Fungi kingdom
• Mushrooms, puff balls, shelf fungi, mycorrhizae and plant parasites
• many are decomposers
• Defined by a cubelike structure called the basidium, a transient diploid stage.
• Reproduces sexually by producing elaborate fruiting bodies called basidiocarps (mushrooms)

• Vertebrates, Deuterostomia
• Slow moving sessile marine animals
• Have a thin epideris that is calcified
• Water vascular system (network of hydrolic canals branching into tube feet that function in locomotion and feeding)
• Seperate sexes, external fertilization
• Radial like symmetery with multiples of 5 (starfish)
• Larvae have bilateral symmetry
• Classes: Asteroidea, Ohiuroidea, Echinoidea, Crinoidea, Holothuroidea

• Phylum: Echinodermata
• Sea Stars
• Multiple arms radiating from a central disk
• Feed on bivalves by prying them open with their tube feet

• Phylum: Echinodermata
• Brittle Stars
• Distinct disk with long flexible arms which they use for movement
• Some are suspension feeders, some are predators

• Phylum: Echinodermata
• Sea Urchins and sand dollars
• Have no arms but 5 rows of tube feet
• Spines are used for locomotion and protection
• Mostly feed on seaweed

• Phylum: Echinodermata
• Sea lillies and feather stars
• Suspesion feeders can live attached to the substrate stalk.
• Feather stars can crawl using long flexible arms

• Phylum: Echinodermata
• Sea cucumbers
• lack spines, reduced endoskeleton
• have 5 rows of tube feet, some are modified feeding tubes

• Major phylum
• 2 clades of invertebrates, rest are vertebrates
• Body plan: Notochord, Dorsal hollow nerve cord, pharyngeal slits or clefts, and muscular post anal tail

• found in chordata
• a longitudinal flexible rod between digestive tube and nerve cord.  Provides skeletal support throughout most of the chordate.
• In most a more complex exoskeleton develops

The nerve cord of a chordate embryo develops from a plate of ectoderm that rolls into a tube dorsal to the notochord

• Clefts: in most chordates grooves in the pharynx called pharangeal clefts develop into clits that open to the outside of the body
• Slits:
• suspension feeding structures in many invertebrate chordates,
• gas exchange in vertebrates (not tetrapods)
• develop into parts of the ear, head, and neck in tetrapods

• chordates have a tail posterior to the anus
• in many species its greatly reduced

• Chordata
• Include lancelets
• Are marine suspension feeders that retain characteristics of the chordate body plan as adults
• Invertebrates
• most basic chordate

• Chordata
• Tunicates
• resemble chordates in their larval stage
• sea squirts

• Group
• Have a skull brain, eys, and other sensory organs
• Have a neural crest: gives rise to bones, cartlidge or a skull
• Have higher metabolism and are more muscular than invertebrates, lancelets and tunicates
• Have: Heart with at least 2 chambers, red blood cells, kidneys
• ~530 mya we see origin of skulls

• Most basic craniates
• Hag fishes
• lack jaws and vertebrae
• marine, bottom dwelling scavengers

• Group
• Characteristics:
•  Vertebrae enclosing a spinal cord
•  An elaborate skull
•  Fin rays in the aquatic forms

The first vertebrates with mineralized skeletal elements in their mouth and pharynx

• Vertebrates
• Lampreys
• Oldest living lineage of vertebrates
• jawless maring and freshwater
• feed by clamping their mouth onto the side of a fish
• have cartilaginous segments surrounding the notochord and arching partly over the nerve cord

• group
• Evolution of jaws and mineralized skeleton
• Includes sharks, ray-finned fishes through mammalia
• Jaws are believed to be derived from skeletal supports of the pharyngeal slits
• large forebrain
• 3 lineages left today:
•  Chondrichtyes
•  Ray Finned fishes
•  lobe fins (us)

• most basal phylum of vertebrates
• Have a skeleton composed primarily of cartlidge
• sharks, rays and skates

• Embryo development from eggs
• eggs hatch outside the mother's body

• Embryo development from eggs
• Embryo develops within the uterus and is nourished by the egg yolk

• Embryo development from eggs
• Embryo develops within the uterus and is nourished through the yolk sac placenta from the mother's blood

• group
• Evolution of lungs
• nearly all have an endoskeleton
• includes bony fish and tetrapods

• defines the phylums Actinistia, Diponi and Actinpterygii
• Control buoyancy with an air sac known as a swim bladder (a modified lung)
• most are ovipoarous

• group Osterichthyes
• Ray-fnned or bony fish
• Originated during Silurian period
• Have fins supported by long flexible rays used for locomotion and defense
• Include seahorses

• group
• us included in lobe fins
• have rod shaped bones surrounded by muscles in their pelvic and pectoral fins

• groups
• Have specific adaptations
• 1) Four limbs and feet with digits
• 2) have a neck which allows for separate movement of head
• 3) fusion of pelvic bone and girdle to backbone
• 4) the absence of gills
• 5) ears for detecting airborne sounds

• Evolution of the tetrapod
• "fish a pod"
• ~375 MYA

• Clade
• Body plan: undergo metamorphosis from an aquatic larva into a terrestrial adult
• most have moist skin that complements the lungs in gas exchange
• Fertilization is external and requires a moist enviroment
• contains:
• 1) Urodela, ie salamanders
• 2) Anura, frogs and toads
• 3) Apoda, legless salamanders

salamanders

Frogs and toads

Caecilians (legless salamanders not snakes)

• group
• All reptiles, birds and mammals
• major derived character is amniotic egg
• relatively impermeable sking and ability to use ribcage to ventilate the lungs
• split from common ancestor ~350MYA

• contains 4 extraembryonic membranes
• 1) Amnion (protection)
• 2) Allatois (wastes and gas exchange)
• 3) Chorion (gas exchange)
• 4) Yolk sac (storage of nutrients for embryo)

• Includes: Tuataras, lizards, snakes, turtles, aves, crocodilia, and extinct dinosaurs
• Have scales that create a waterproof barrier.  Lay shelled eggs on land
• most are ectothermic - aves are endothermic
• ~359-299 MYA

• Turtles
• have a boxlike shell made of upper and lower shields that are fused to the vertebrae, clavicles and ribs
• Phylogenetic placement not yet determined

• Birds or archosaurs adapted for flight
• HAve:
• 1) Wings with keratin feathers
• 2) lack a urinary bladder
• 3) females with 1 ovary
• 4) small gonads
• 5) loss of teeth
• May have evolved from theropods
• Early feathers may have helped dinosaurs gain lift when they jumped, gain traction running up hills, or helped glide from trees

Lizards and snakes

• "Milk"
• +/- 5000 species
• Have:
• 1) Mammary glands
• 2) Hair
• 3) A high metabolic rate due to endothermy
• 4) larger brain than vertebrates of equivalent size
• 5) differentiated teeth
• Evolved from synapdids (a characteristic of which is the fenestra - a hold behind the eye socked to support muscles).
• By ~140MYA 3 living lineages of mammals emerged
• Lineages: Monetremes, Marsupials, Eutherians

• Mammals
• Small group of egg laying mammals consists of echidnas and platypus. 
• No nipples instead have an area of skin that sweats milk

• Mammals
• Opossums, kangaroos, and kooalas.
• Embryo develops within a placenta in the mother's uterus.  Born very early and finishes development in mother's pouch called a marsupium

• Mammals
• More complex placenta
• Complete embryonic development inside a uterus joined to the mother by the placenta

• A sequence of unlearned, innate behaviors that is unchangeable.
• Once initiated it is usually carried to completion
• Triggered by an external cue, known as stimulus
• Example: Male stickleback fish see the red underside of an intruder and attack

• Migration is regular, long-distance change of location
• Environmental cues can trigger movement in a particular direction

• He smells a female's chemicals in the air
• (step 1 in drosophila melanogaster courtship)

• He sees the female and orients his body toward her
• (step 1 in drosophila melanogaster courtship)

• He taps the female with a foreleg
• (step 2 in drosophila melanogaster courtship)

• He chemically confirms the female's identity
• (step 2 in drosophila melanogaster courtship)

• The male produces a courtship song to inform the female of his species
• (step 3 in drosophila melanogaster courtship)

Honeybees show complex communication with symbolic language

A bee returning from the field performs a dance to communicate information about the distance and direction of a food source

• Innate behavior is developmentally fixed and does not vary among individuals
• Some behavior is influenced by the environment
• A cross-fostering study places the young from one species in the care of adults from another species
• – e.g California mice and white-footed mice

Learning is the modification of behavior based on specific experiences

• Imprinting is a behavior that includes learning and innate components and is generally irreversible.
• It is distinguished from other learning by a sensitive period.
• A sensitive period is a limited developmental phase that is the only time when certain behaviors can be learned

• Spatial learning based on experience with the spatial structure of the environment.
• Animals build cognitive maps – a representation of spatial relationships between objects in it’s surroundings.

• In associative learning, animals associate one feature of their environment with another.
• – operant conditioning
• – classical conditioning

Cognition is a process of knowing that may include awareness, reasoning, recollection, and judgment

Problem solving is the process of devising a strategy to overcome an obstacle.

Social learning is learning through the observation of others and forms the roots of culture.

Culture is a system of information transfer through observation or teaching that influences behavior. – can alter behavior and fitness of individuals.

No strong pair-bonds or lasting relationships

• One female with one male
• Monogamous species tend to be less sexually dimorphic
• If the offspring required lots of resources A male maximizes his reproductive success by staying with his mate, and caring for his checks (monogamy).

• individual of one sex mates with several individuals of the other sex
• Polygamous species tend to be more sexually dimorphic.
• polygynous: male more showy,one male mates with many females
• polyandrous :female more showy, one female mates with many males
• If the offspring required few resources A male maximizes his reproductive success by seeking additional mates (polygyny).

• Certainty of paternity influences paternal care and mating behavior.
• Paternal certainty is relatively low in species with internal fertilization. – more paternal care
• Paternal certainty is high in species with external fertilization. – little paternal care

• Sexual dimorphism results from sexual selection, a form of natural selection.
• In intersexual selection, members of one sex choose mates on the basis of certain traits.
• Intrasexual selection involves competition between members of the same sex for mates.

Sometimes animals behave in ways that reduce their individual fitness but increase the fitness of others

Three key variables involved in an altruistic act – Benefit to the recipient (B) – Cost to the altruistic (C) – Coefficient of relatedness (r)

Inclusive fitness is the total effect an individual has on proliferating its genes by producing offspring and helping close relatives produce offspring

• Fraction of genes that, on average, are shared
• – parent-offspring = 0.5 
• – full-sibs = 0.5
• – uncle = 0.25
• – cousins = 0.125

• Natural selection favors altruism when
• rB > C

• Benefit to the recipient (B)
• Cost to the altruistic (C)
• Coefficient of relatedness (r)

• Ecology is the scientific study of the interactions between organisms and the environment.
• These interactions determine distribution of organisms and their abundance

• Organismal ecology studies how an organism’s structure, physiology, and (for animals) behavior meet environmental challenges.
• Organismal ecology includes physiological, evolutionary, and behavioral ecology

• A population is a group of individuals of the same species living in an area.
• Population ecology focuses on factors affecting population size over time.

• A community is a group of populations of different species in an area.
• Community ecology deals with the whole array of interacting species in a community

• An ecosystem is the community of organisms in an area and the physical factors with which they interact.
• Ecosystem ecology emphasizes energy flow and chemical cycling among the various biotic and abiotic components.

• A landscape or seascape is a mosaic of connected ecosystems.
• Landscape ecology focuses on the exchanges of energy, materials, and organisms across multiple ecosystems.

• The biosphere is the global ecosystem, the sum of all the planet’s ecosystems.
• Global ecology examines the influence of energy and materials on organisms across the biosphere.

• The long-term prevailing weather conditions in an area constitute its climate.
• Climate is shaped by four major abiotic components:
• – temperature
• – precipitation
• – sunlight
• – wind

• Global climate change caused by humans. – Emission of greenhouse gasses
• • Fossil fuels
• • Agriculture
• • Land use change

• Microclimate is determined by fine-scale differences in the environment that affect light and wind patterns
• Every environment is characterized by differences in:
• – Abiotic factors, including nonliving attributes such as temperature, light, water, and nutrients.
• – Biotic factors, including other organisms that are part of an individual’s environment.

• Biomes are major life zones characterized by vegetation type (terrestrial biomes) or physical environment (aquatic biomes).
• Climate affects the latitudinal patterns of terrestrial bones
• Biomes are affected by the mean and variance in temperature and precipitation.

• Density is the number of individuals per unit area or volume.
• Sampling techniques can be used to estimate densities and total population sizes.
• Population size can be estimated by: – extrapolation from small samples – an index of population size – mark-recapture method
• Density is the result of an interplay between processes that add individuals to a population and those that remove individuals

• Dispersion is the pattern of spacing among individuals within the boundaries of the population
• Environmental and social factors influence the spacing of individuals in a population
• Clumped Dispersion: In a clumped dispersion, individuals aggregate in patches. A clumped dispersion may be influenced by resource availability and behavior
• Uniform Dispersion: A uniform dispersion is one in which individuals are evenly distributed. It may be influenced by social interactions such as territoriality.
• Random Dispersion: In a random dispersion, the position of each individual is independent of other individuals.  It occurs in the absence of strong attractions or repulsions

Demography is the study of the vital statistics of a population and how they change over time.

• Type I: low death rates during early and middle life and an increase in death rates among older age groups
• Type II: a constant death rate over the organism’s life span
• Type III: high death rates for the young and a lower death rate
• for survivors

• Exponential population growth is population increase under idealized conditions
• Under these conditions, the rate of increase is at its maximum, denoted as rmax
• Exponential growth cannot be sustained for long in any population

• Carrying capacity (K) is the maximum population size the environment can support.
• Carrying capacity varies with the abundance of limiting resources

• In the logistic population growth model, the per capita rate of increase declines as carrying capacity is reached
• Exponential model + an expression that reduces per capita rate of increase as N approaches K

• An organism’s life history comprises the traits that affect its reproduction and survival
• – Age at which reproduction begins
• – How often the organism reproduces cycle
• – How many offspring are produced during each reproductive cycle
• Species that exhibit semelparity reproduce once and die
• Species that exhibit iteroparity produce offspring repeatedly