the idea that either the egg or the sperm contained a complete preformed individual (homunculus)
how many cells in the human body?
how many species of animals?
2 characteristics of vertebrates
- 1. enclosed spinal cord
- 2. elaborate skull
4 characteristics of chordates
- 1. notochord
- 2. hollow nerve cord dorsal to notochord
- 3. pharyngeal pouches
- 4. endostyle
the unfolding development of an organism, in particular the development of a plant or animal from an egg or spore through a sequence of steps in which cells differentiate and organs form
- 1. molecular developmental biology
- 2. evolutionary biology
- main goal: study evolution of the genomic 'toolkit' common to all animals
- longest division of geological time
- i.e. eonothem, half a billion years or more
- major division of geological time, usually divided into 2 or more periods
- i.e. erathem, several hundred million years
tens of millions of years
cretaceous was ___ mya. follows ____ and is followed by ___.
- 145-65 mya
jurrassic was ___ mya. follows ____ and is followed by ___.
- 199-145 mya
cambrian was ___ mya. followed by ____.
geological epoch that began approx 12kya
a phase early in the development of most animal embryos during which the ectoderm, mesoderm and endoderm form
a set of morphological and developmental traits
4 characteristics of bilaterally symmetrical
- 1. dorsal (top) and ventral (bottom) sides
- 2. right and left sides
- 3. anterior (head) and posterior (tail)
- 4. cephalization (development of a head)
the study of RNA
how many phyla are there?
when did multicellular life appear?
when did bilaterian life appear?
4 characteristics of animals
- 1. multicellular eukaryotes
- 2. lack cell walls
- 3. bodies held together by collagen
- 4. nervous tissue and muscular tissue
layer covering embryo's surface
innermost germ layer lining developing digestive tube (archenteron)
ecto and endoderms
ecto, endo, mesoderms (all bilaterians)
embryonic stem cells
can generate all embryonic cell types
adult stem cells
cells that generate a limited number of cell types
stages in zygote development
- 1. zygote
- 2. 8 cell stage
- 3. blastula
- 4. gastrula
blastopore becomes ____ in protostome development
blastopore becomes ___ in deuterostome development
group of protostome animals including Arthropoda, Nematoda
a group of protostome animals including trochozoans and lophophorata
in deuterostome development, cleavage is ___ and ____.
each cell in early stages of cleavage retains the capacity to develop into a complete embryo; makes identical twins and embryonic stem cells possible
sexually immature and morphologically distinct from adult, eventually undergoes metamorphosis
when was the evolutionary big bang?
when was the mass extinction of 22% marine families?
when was the mass extinction of 21% families overall?
250 mya (end of triassic period)
longitudinal, flexible rod b/w digestive tube and nerve cord. provides skeletal support
develops from plate of ectoderm that rolls into a tube dorsal to the notochord; develops into central nervous system
two groups of invertebrate deuterostomes
example of urochordate
tunicate. have notochord, lack head
example of chephalochordate
specify the location in an embryo that leads to the development of specific structures in that location
3 examples of hox genes
- BF1 - forebrain
- Otx - midbrain
- HOx3 - hindbrain
when did craniates come about?
what is unique to craniates?
neural crest: collection of cells near dorsal margins of closing neural tube in embryo
what is the name for the group that includes sharks, rays, etc?
the vast majority of vertebrates belong to a clade of gnathostomes called
when did tetrapods come on land?
how many species of amphibians are there?
when did amphibians come about?
3 characteristics of amniotes
- 1. amniotic egg
- 2. relatively impermeable skin
- 3. ribcage to ventilate lungs
when did reptiles come about?
3 characteristics of reptiles
- 1. scales -> waterproof
- 2. shelled eggs laid on land
- 3. most are ectothermic
flight enhances what 4 things in birds?
- 1. hunting
- 2. scavenging
- 3. escape
- 4. migration
what makes up feathers and wings?
4 characteristics of primates
- 1. large brain, short jaws
- 2. forward looking eyes close together for depth perception
- 3. complex social behavior, parental care
- 4. fully opposable thumbs (monkeys/apes)
5 characteristics of humans
- 1. upright posture, bipedal locomotion
- 2. larger brains
- 3. language, symbolic thought
- 4. manufacture and use of complex tools
- 5. shortened jaw and digestive tract
when did hominins begin to walk long distances on 2 legs?
4 characteristics of Neanderthals
- 1. lived in Europe and Near East 200-28kya
- 2. thick boned, larger brain
- 3. buried dead
- 4. made hunting tools
what was the first hominin out of africa?
Homo erectus, 1.8 mya
when did the Homo sapiens come about, and where?
195kya in africa
area needed to support a population's lifestyle
what is the estimated range of human population?
the maximum population size the environment can support
what hominin lived 6.5 mya?
what hominin lived 6mya?
what hominin lived 5.75-4.5mya?
what hominin lived 4.5-4mya?
what hominin lived 3.7-3 mya?
what hominin lived 4-3mya?
what hominin lived 3-2.4mya?
what hominin lived 2.5 mya?
what hominin lived 2.3-1.3mya?
what hominin lived 2-1.5mya?
what hominin lived 2.4-2.1mya?
what hominin lived 2.4-1.6mya?
what hominin lived 1.9-1.5mya?
what hominin lived .25mya?
what hominin lived 1.8-?mya
what hominin lived .25mya?
cenozoic era was ___ years ago
when do animals go to land?
when was the cambrian explosion?
when did the common ancestor live?
3 hypotheses of cambrian explosion
- 1. new food sources and predator-prey relationships
- 2. rise in atmospheric O2
- 3. further evolution of Hox gene complex
how many species of nematodes?
5 characteristics of nematodes
- 1. covered by tough cuticle, must molt
- 2. alimentary canal, lack circulatory system
- 3. pseudocoelomates
- 4. reproduce sexually through internal fertilization
- 5. parasitic nematodes can redirect cellular functions of hosts to avoid their immune systems
annelids have 3 subgroups
- 1. Oligochaeta - earthworms
- 2. Polychaeta - polychaetes
- 3. Hirudinea - leeches
why both doing "extreme environment" research? (6)
- 1. discover new ecosystems
- 2. investigate novel kinds of biology (ecosystem based on chemosynthesis)
- 3. understand new potentials for sources of bioenergy
- 4. evolution of early life in 'primitive' hot-vent conditions
- 5. examine possibility of life on other 'hot' planets
- 6. new biotechnological applications
how many species of vertebrates?