Ecology

Phylogeny: the evolutionary history (development) of a species or a group.

Systematics: the study of classifying organisms and determine their evolutionary relationships. Fossils, molecules, and genes are used to tell their relationships. This information is used to make a tree of life.

Cladistics: the approach to systematic. It is common ancestry is the primary standard used to classify organisms.

Taxonomy: the practice of how organisms are named and classified. The applications of systematics

Binomial nomenclature is the common names for organisms that refer to more than one species. It is italicized and there are two parts: the genus (group) to which a species belongs, and the specific epithet (it is unique for each species)

• He founded the two-part (binomial) naming system.
• Classification system: DKPCOFGS
• Domain, kingdom, phyla, class, order, family, genus, species

• It is a branching diagram where the evolutionary history of a group of organisms can be represented. It can trace evolutionary relationships and it can find two species’ common ancestor.
• You can’t tell when the species evolved or how much change occurred. It also called a gene tree.

• 
• branch points/nodes, sister taxa, polytomy, and the most recent common ancestor for all taxa on the diagram.
• Branch points: it represents the divergence of 2 evolutionary lineages from a common ancestor.
• Sister taxa: groups that share an intermediate common ancestor (closest relatives)
• Polytomy: a branch point where 2 or more descendant groups come out.

• We must not assume that a taxon on the tree evolved from the taxon next to it, it just means they evolved from a common ancestor.
• We also cannot assume the ages of a particular species or when it evolved and how much change occurs, it just shows the pattern of descent.

• Homology: similarity in characteristics resulting from a shared ancestry.
• Analogy: similarities between 2 species that is caused by convergent evolution.
• Homoplasy: analogous structures or molecular sequence that has evolved independently in 2 species.
• Analogous structures: body parts that resemble one another in different species, but they evolved independently as adaptations to their environments.
• Homologous structures: structures in different species that are similar because of common ancestry. The have different functions but similar internal and external structure and development.

• Homologous structures: human arm, a cat’s forelimb, a whale’s fin, and a bats wing/ skulls of a human and a monkey
• Analogous structures: fins of sharks and penguins / large from paws and small eyes of different moles / a bats wing and a birds wing

• Molecular homology is the similarity in arrangement of genes or DNA sequences.
• The more points of resemblance two species have in their DNA sequences the more likely they are closer related.
• For example, a human and a chimpanzee do not seem closely related but they are due to the similarities in their skull structures. Their genes are inherited from a common ancestor.

• Clades: a group which includes an ancestral species and all of its descendants. They are grouped within larger clades.
• Taxon: a named taxonomic unit at any given level of classification
• They are the same only if it is monophyletic (it consists of an ancestral species and all its descendants)

• Monophyletic: a group that consists of an ancestral species and all its descendants
• paraphyletic: a group that consists of an ancestral species and some of its descendants (not all of them)
• Phylogenetic: a group that consists of taxa with different ancestors (add one)

• Ancestral character: a character that originated from in an ancestor of the taxon unit. Ex: the backbone in all vertebrates.
• Shared derived character: a characteristic unique to a certain clade and shared by it but not found in its ancestor. Ex: the hair on most mammals is not found in their ancestor.

• Outgroup is the group or species that departed before the lineage that contains the group we are studying. Its members are closely related to the ingroups.
• By comparing the two, we can tell which characteristics came about and at what branch points.

• It is a tree that requires the fewest base changes.
• It is looking for the simplest explanation that is consistent with the facts.
• It helps narrow the possibilities of arranging species in a tree.

• They represent a guess about how various organisms in the tree are related to one another.
• Tests and experiments can be done based on the tree.
• Phylogenetic bracketing helps us make predictions that characteristics shared by two groups of related organisms are present in the rest of the descendents and in their common ancestor.

• a. Biosphere-It is the global ecosystem. The ecosystem is composed of all the regions of the earth that contain living things.
• b. Ecosystem -It is the interrelationship between the organisms of a community and the physical factors they interact with.
• c. Community -A community is a group of populations living in the same area.
• d. Population -It is a group of individuals of the same species living in the same area

• Biotic (living) factors: predators, parasitism, competition, pathogens, food resources, and herbivores
• Abiotic (nonliving) factors: Temperature, water (precipitation), salinity, sunlight, rocks and soil (PH of soil or water), and wind.

It is the movement of individuals away from their area of origin or from places of high population. It influences distribution because organisms are populating new areas. Then these organisms are geographically isolated so they evolve into a different population. Natural range expansion is when organisms reach an area where they did not exist previously. A species transplant is successful when they survive the new area and reproduce.

Water: When terrestrial animals obtain and conserve water their ability to distribute increases.

Temperature: effects biological processes. Most organisms function and survive better in a specific range of temperature.

Predators: they kill their prey and limit distribution

Herbivores: eat plants which limit food supply that limits distribution

Biome: the major terrestrial or aquatic life zones. Each biome is occupied by unique communities or ecosystems of plants and animals that share adaptations, which promotes survival.

The aquatic biome is the largest because more than half of the earth is covered in water. The oceans make up 75% of the earths surface. It has enormous impact on the biosphere.

Marine biomes cover approximately 75% of the earth’s surface and have an enormous effect on the biosphere.

• The physical environment: The top of the water absorbs more light (photic zone) contains more life. There is sufficient light for photosynthesis in the upper photic zone.
• Chemical “ “- the amount of nutrients and oxygen in the lake
• Geological features- add runoff that provides nutrients

• Oligotrophic: nutrient poor and oxygen rich
• Eutropic: nutrient rich and depleted of oxygen

• are areas covered with sufficient water to support aquatic plants.
• They can be saturated or periodically flooded.
• Wetlands include marshes, bogs, and swamps.
• They are among the most productive biomes on Earth and are home to a diverse community of invertebrates and birds.
• Because of the high organic production and decomposition in wetlands, their water and soil are low in dissolved oxygen.
• Wetlands have a high capacity to filter dissolved nutrients and chemical pollutants.
• Humans have destroyed many wetlands, but some are now protected.

• are bodies of water moving continuously in one direction.
• Headwaters are cold, clear, turbulent, and swift.
• They carry little sediment and relatively few mineral nutrients.

• is the open blue water, mixed by wind-driven oceanic currents.
• The surface waters of temperate oceans turn over during fall through spring.
• The open ocean has high oxygen levels and low nutrient levels.
• This biome covers 70% of the Earth’s surface and has an average depth of 4,000 meters.

• are limited to the photic zone of stable tropic marine environments with high water clarity. They are found at temperatures between 18°C and 30°C.
• Coral reefs are home to a very diverse assortment of vertebrates and invertebrates.
• Global warming and pollution contribute to large-scale coral mortality.

• consists of the seafloor below the surface waters of the coastal or neritic zone and the offshore pelagic zone.
• Most of the ocean’s benthic zone receives no sunlight

• are found close to the equator.
• Tropical rain forests receive constant high amounts of rainfall
• In tropical dry forests, precipitation is highly seasonal.
• Tropical forests are stratified, and competition for light is intense. Animal diversity is higher in tropical forests than in any other terrestrial biome.

• Deserts occur in the interior of continents.
• Deserts have low and highly variable rainfall
• Temperature varies greatly seasonally and daily.
• Desert vegetation is usually sparse and includes cacti and deeply rooted shrubs.
• Many desert animals are nocturnal, so they can avoid the heat.
• Desert organisms display adaptations to allow them to resist or survive desiccation.

• Savanna is found in equatorial and subequatorial regions.
• Rainfall is seasonal,
• The savanna is warm year-round
• Savanna vegetation is grassland with scattered trees.
• Large herbivorous mammals are common inhabitants.
• The dominant herbivores are insects, especially termites.
• Fire is important in maintaining savanna biomes.

• Chaparrals have highly seasonal precipitation with mild, wet winters and dry, hot summers.
• Chaparral is dominated by shrubs and small trees, with a high diversity of grasses and herbs.
• Plant and animal diversity is high.
• Adaptations to fire and drought are common.

• Temperate grasslands exhibit seasonal drought, occasional fires, and seasonal variation in temperature.
• Large grazers and burrowing mammals are native to temperate grasslands.
• Deep fertile soils make temperate grasslands ideal for agriculture, especially for growing grain.
• Most grassland in North America and Eurasia has been converted to farmland.

• Coniferous forest, or taiga, is the largest terrestrial biome on Earth.
• Coniferous forests have long, cold winters and short, wet summers.
• The conifers that inhabit these forests are adapted for snow and periodic drought.
• Coniferous forests are home to many birds and mammals.
• These forests are being logged at a very high rate and old-growth stands of conifers may soon disappear.

• Temperate broadleaf forests have very cold winters, hot summers, and considerable precipitation.
• A mature temperate broadleaf forest has distinct vertical layers, including a closed canopy, one or two strata of understory trees, a shrub layer, and an herbaceous layer.
• The dominant deciduous trees in Northern Hemisphere broadleaf forests drop their leaves and become dormant in winter.
• In the Northern Hemisphere, many mammals in this biome hibernate in the winter, while many bird species migrate to warmer climates.
• Humans have logged many temperate broadleaf forests around the world.

• Tundra covers large areas of the Arctic, up to 20% of the Earth’s land surface.
• the plant communities in alpine and Arctic tundra are very similar.
• The Artic tundra winter is long and cold, while the summer is short and mild.
• The growing season is very short.
• Tundra vegetation is mostly herbaceous, consisting of a mixture of lichens, mosses, grasses, forbs, and dwarf shrubs and trees.
• A permanently frozen layer of permafrost prevents water infiltration and restricts root growth.
• Large grazing musk oxen are resident in Arctic tundra, while caribou and reindeer are migratory.
• Migratory birds use Arctic tundra extensively during the summer as nesting grounds.
• Arctic tundra is sparsely settled by humans but has recently become the focus of significant mineral and oil extraction.

• ·The proximate cause of a behavior means how the behavior of an animal occurs
• or how it is modified. It asks about what stimulus brings out the behavior and
• how does the animals experience during growth influence the response.

• The ultimate cause of a behavior is why the behavior occurs. It asks how the
• behavior aid survival or reproduction? And what is the evolutionary history of
• the behavior?

A possible proximal cause would be vocal cords of the cockatoos that make the sound.

• A possible ultimate cause is that the males screech for an hour at dusk because they cannot be seen that well by
• predators because the sun is setting. That is also when the females come out to get food so the males go out to get their attention. They do it at the beginning of the mating season because that is when female’s hormones are very responsive.

• · Fixed
• action is a type of behavior that is linked to a simple stimulus. It is a behavior that in unchanging and follow a regular pattern. It is carried out to completion.

• · A sign stimulus is an external cue that triggers a fixed action pattern.
• Ex: Male sticklebacks attack other males with red bellies that invade their nest.

They are innate behaviors because those patterns are triggered by any stimulus, even if they are unreal. Once it is initiated it does not stop until it is completed. If it was a learned pattern they would know not to react to the unreal stimulus. It is instinct.

· Kinesis is an undirected change in activity or speed of an animal’s movement in response to a stimulus. They happen in changing locations. The animal will stay longer in the environment it favors.

Ex: Sow bugs demonstrate kinesis movements in response to variation in humidity. They move around a lot in dry areas because dry areas act as a stimulus. Their increased movements in dry areas show that they will probably leave that area. They are less active when they are in humid areas, so they will go towards these areas because they survive better there.


· Taxis is an oriented movement towards (positive) or away (negative) from some stimulus. It is a directed movement.

Ex: trout swim upstream to keep themselves from being swept away and that way they are facing the direction their food comes from.

A behavior rhythm is a behavior that maintains rhythmic activity under constant conditions.

• Behavioral rhythms are linked to the yearly cycle of seasons, which are called circannual rhythms and circadian
• rhythms, where behavior links to the daily cycle. Some behaviors are timed with the lunar cycle.

Ex: Male fiddler crabs wave their claws next to their burrow to attract mates when there is tidal movement. This behavior happens around that time because the tides take the larvae into deeper waters where they can complete their development and be safe.

• • Visual communication: when information/identification flows from one mate to the other by the visual
  • system.
  
  · Chemical communication: when the male’s sense of smell detects chemicals that were released by the female.
  
  · Tactile communication: is when the male makes the female aware of his presence by behaviors like tapping.
  
  
  • · Auditory communication: when one the male confirms that he’s of the same species by a specific courtship song

Pheromones are chemicals or odors that are emitted so that animals can communicate. They are the basis for chemical communication because they trigger specific behaviors. Pheromones serve as signals for mating, guides for food sources, or alarms for danger. For example, they are the chemical communication in fruit fly courtship and for a catfish’s alarm substance.

a) Habituation: a learned behavior that results in a loss of responsiveness to a stimulus that has no effect on their fitness because they are meaningless and provide no new information. It allows the animal to focus on only the stimuli that increase their fitness, like ones that signal the presence of food a mate, or real danger.

EX: A bird recognizes alarm calls from members of their species that warn them of danger. They learn to stop responding to these calls once they see that the calls are not followed by an attack or any danger.

• b) Imprinting: It
• is a behavior that is learned and becomes innate. A new behavior is learned during a critical/sensitive period in the animals’ life. It then becomes a lifetime behavioral response to an object or individual. The imprinting stimulus is an innate response that is directed to the first object the animal encounters.

EX: Just hatched graylag geese accept any moving object as their mother. Their critical period only lasts for a day and after that they will not accept anything else as their mother.

c) Spatial Learning: the institution of a memory that reflects the environments spatial structure. It learns things relative to visible landmarks.

EX: Wasps locate their nest by nearby landmarks, like pine cones. When the pine cones were moved to another location that did not contain the nest, the wasp still flew to that area.

d) Associative Learning: It occurs when an animal learns by its ability to associate environmental features with another. There is classical conditioning where a stimulus becomes associated with a particular outcome, like when a bell rings a dogs mouth will automatically salivate because they think food is coming. There is also operant conditioning where an animal connects a behavior with a particular response, like an award or harm.

EX: A coyote learns to avoid porcupines because when it approached it, it got a face full of quills.

A lion cub learning how to hunt from an adult lion is a learned behavior, but it is also innate because it is instinct to capture prey. Another one is a cat chasing a lizard because it observes other cats doing it so it learns to do that, and it is innate for them to chase the lizard. A common example is birds learning how to sing songs.

It is food obtaining behavior, like eating, and other activities that help the animal search for, recognize, and capture food items.

Optimal foraging model / Natural selection favors foraging behaviors that minimizes the cost of foraging, like energy and the risk of predation and maximizes the benefits. Whatever behavior requires less work will be acted on and evolve because it results in more benefits.

15 minutes = 120 calories

3 minutes

Polgyny (a single male with manyfemales) is more common than polyandry (a single female mating with many males)because it maximizes the males reproductive success. Males are usually moreshowy and noticeable so they get more mates. Some mammal offspring only needthe lactating female so the males just go off and mate with other females.Certainty of paternity issometimes low so the males do not stay around to raise the offspring becausethey do not know if it is theirs. Malesjust want to pass their genes on.

They engage in a ritual display because theconsequences are psychological rather than physical. It’s a contest thatdetermines which competitor can get access to resources, food, mates, andterritory. Ritualized displays also minimize the injuries and time spent in acontest. The game theory says that the outcome depends on the strategies of theindividuals involved.

It is unselfish behavior thatreduces the fitness of an individual but may increase the fitness of anotherindividual. It can be manipulated because an animal can increase its geneticrepresentation by selflessly helping their close relatives. The animalsinclusive fitness, its fitness plus the fitness of its relatives, evolve byselection. Kin selection can favor those who help their siblings or help themreproduce more siblings.

• a. Your dog b. Your sister c. 3 cousins d. Your uncle
• Explain your choice.

My sister because we are closely related and share the same genes. Our fitness will then increase by kin selection.

The environment an animal israised in influences its behaviors. An animals genetic makeup providesinstructions for a behavior but the environment of the fertilized egg and itsdiet, social interactions, and surroundings change out those instructions arecarried out. Behavior is a result of genes (nature) or environment (nurture).

Twin study: where researcherscompare the behavior of identical twins raised apart with those raised in thesame household. Their environment and genetics contribute to the behaviors thatcharacterize disorders. Cross-fostering study: when oneyoung offspring of one species is placed in the care of adults from anotherspecies. That offspring will acquire the behavior of the species that raised itand not their own (mice example).

Density: the number of individuals per unit area or volume.

• Dispersion: how individuals in a population are distributed. It’s the patter of spacing among individuals
• within boundaries of the population

Demographics: the study of vital statistics of populations and how they change over time.

• Mark-recapture method: used when ecologists can’t count all the individuals in a population. They capture a
• random sample and they mark each individual and release it.

• X(# of marked animals recaptured) n(total # of animals captured) m(# of animals marked in the first
• capturing) N (estimated population size) N = mn/x

population. Death and emigration (when individuals move out of a population) result in a decrease.

• They can be clumped (grouped together) because it can increase their chance of mating, or it’s a favorable
• environment, or it can increase the effectiveness of certain predators. It’s most common

• They can be uniform (evenly spaced due to interactions with other individuals of the population). It is a
• result of territoriality.

They can also be random (unpredictable spacing) due to the lack of strong attractions.

• Type 1 curve describes specieswhere most individuals survive to middle age and have a high death rate afterthat. There are low death rates during early and middle life. humans
• Type 2 curves are intermediatesurvivorships with a constant death rate. The likelihood of death is the sameat any age. rodents
• Type 3 curves show that mostindividuals die young. There are high death rates for the young. clams

• Semelparity (big-bang production) is when an organism produces a large amount of eggs in a single
• reproductive opportunity before they die. Ex: salmons return to the fresh water
• stream where they were born and produce thousands of eggs before they die. it
• occurs when the survival rate of offspring is low, so they produce a lot so
• some will survive.

• Iteroparity (repeated reproduction) is when an organism produces offspring more than once in their
• lifetime. Occurs in dependable environments where adults are most likely to
• survive and reproduce.

The conditions are crowding, resource limits, lacking predators and competition, and a large or small population.

• It is the maximum number of individuals of a population (population size) that can be sustained by a
• particular habitat (environment). It varies over space and time with the abundance of limiting resources like water, energy, shelter, refuge, nutrient availability, and nesting sites.

• K-selection is selection that favors life history traits that are sensitive to population’s density, like
• adaptations that allow organisms to survive and reproduce with low resources. It operates in populations where there is high competition and where it is near its carrying capacity. EX: mature trees that are growing in an old-growth
• forest.

r-selection is selection that favors traits that maximize reproductive success in low density (uncrowded) populations, like adaptations that produce rapid reproduction. It occurs in environments where pop. Densities are below carrying capacity and where there is little competition. EX: insects that reproduce rapidly.

Birth rates and death rates are density dependent when those rates rise as the population rises.

EX: dune fescue declines as population density increases due to the competition for water and nutrients.

Grass populations birth rates are density dependent.

Competition for Resources: increasing density intensifies competition for resources. This results in lower birth rates.

Territoriality: it can limit population density. It is a resource organisms compete for. If a bird cannot obtain a nesting spot it will not reproduce.

• Disease: population density has an effect on the health and
• survival of organisms. Organisms can experience an increase rate of infections by pathogens at high population densities.

Predation: when the population density of the prey increase the predator will consume a higher percentage of individuals.

• Toxic Wastes: increase in pop results in an increase of
• toxic waste that can poison organisms in that environment.

• Intrinsic (psychological) factors: There can be a drop in reproduction that is associated with aggressive interactions that increase with pop. Density and it can even happen when there is food and shelter. High pop
• densities in mice can induce hormonal changes that delay sexual maturation and cause reproductive organs to shrink.

Community ecology is the studyof the kinds of interactions that occur between species in a community.Co-evolution is significantbecause it is the development of species that live together and in communityecology, the interactions between the two species can harm, hurt, or do nothingto each other. It is the evolution of one species in response to new adaptationthat come about in the other species. Selection promotes the mostsuccessful predators and harder to pin down prey leads to coevolution ofpredator and prey. Two species evolve so that mutual benefits increase.

It is the local elimination ofan inferior competitor I an environment where two species live. Two speciescannot coexist when they are competing for the same resources or their nichesare identical.

It is the sum of a species useof the biotic and abiotic resources in its environment. An organism’s niche isits ecological role (how it “fits into” an ecosystem). Niche is an ecologicalrole.EX: the niche of a tropicaltree lizard is made up of the temperature range it lives in, the kinds ofinsects it eats, the size of branches onwhich it perches, and the time of day when it is active. A ladybug’s niche consists ofthe plants it lives on, the little bugs it eats, the time of day it goes out toeat, and the temperature it lives in.

They have greater differencesbecause they compete for resources. That competition results in a divergence incharacteristics because they eventually use different resources. Naturalselection resolves competition so two different species can coexist by theevolution of niche differentiation. Selection results in one of the speciesusing a different set of resources thus altering their morphology.

a. Cryptic and aposematic coloration: Cryptic coloration is camouflage, which makes itdifficult for predators to spot the prey. It is a psychologically andmorphologically adaptation.Aposematic coloration iswarning coloration that is usually bright colors that mean the animal haseffective chemical defenses, like poison. It is adaptive

is when preyand harmless species gain significant protection by mimicking the appearance ofother species that are harmful and unpalatable.

is whentwo or more unpalatable species resemble one another that result in predatorsquickly adapting to avoid any prey with that type of appearance.

a. Parasitism: (+/-) when aparasite gets it nourishment from another organism (host), which is harmed inthe process. There are endoparasitesthat live inside their hosts and ectoparasites that live on the externalsurface of the host. Ticks live on the outside of their host can weaken thembecause they withdraw their blood.

wheninterspecific interactions benefit both species. Acacia trees provide food andhousing for ants and ants kill any insects or fungi found on the tree. The antsalso clip vegetation near the tree so it has space to grow.

arelationship that benefits one species, but neither harms or helps the other. EX:algae that live on shells of turtles or barnacles that attach to whales gain aplace to grow while the turtles and whales are not affected by it.

a. Species diversity: thevariety of different kinds of organisms that make up the community.b. Species richness: the numberof different species in the communityc. Relative abundance: theproportion each species represents of all individuals in the community.

trophic structure: the structureand dynamics of a community depend to a large extent on the feedingrelationships between organisms. The food chain is transfer offood energy up the trophic levels from its source in plants through herbivores,to carnivores, and to decomposers.The food web is how food chainsare linked together. It helps ecologists find the trophic relationships of acommunity by seeing who eats whom.

It is limited by theinefficiency of energy transfer along a food chain (energetic hypothesis).The 10% rule of thumb meansthat only 10% of the energy stored in the organic matter is converted toorganic mater at the next level. Long food chains are less stable (dynamicstability hypothesis). Carnivores limit it because they are large and are moresuccessful.

V->H An in directional influence from lower tohigher trophic levels. EX: the absence of mineral nutrients controls the numberof plants, which control the number of herbivores, which control carnivorenumbers.

Predation controls community organizationbecause they limit herbivores that limit plants, which limit nutrients. EX:lake community- the removal of top carnivores will increase the number of othercarnivores , which decreases the number of herbivores, which increases thenumber of phytoplankton, and that decreases minerals.

The top-down model controls theorganization of a community. It can improve the quality of water in pollutedlakes. They use biomanipulation that prevents algal blooms by changing thedensity of higher level consumers.

Why? What is the nameof the hypothesis that makes this assertion? Intermediate disturbance hypothesis says thatmoderate levels of disturbance can create conditions that can foster speciesdiversity than high or low disturbances. Intermediate disturbance results inthat because it can foster greater species diversity by opening up habitats foroccupation by less competitive species. EX: rare floods and very frequentfloods affected the diversity of a community greatly, while intermediatefrequency caused invertebrate richness.

It is when a disturbed area that is colonizedby a species, gets colonized by another. The original species is graduallyreplaced by another species, and that one is replaced by another species. It isthe change in the composition of species over time.

Primary- occurs in areas thatnever previously supported living things.EX: it happens at volcanicislands that have no soil. They are first colonized by lichen and mosses and asthe soil develops mosses are overgrown by grasses. Then it is eventuallycolonized by plants.Secondary-begins in habitatswhere there is an existing community that is cleared by a disturbance butleaves the soil intact. EX: crop lands begin with thegermination of species (like weeds) from seeds already in the soil. Then treesfollow that region, usually pine trees, and then it is followed by oak,hickory, or dogwood trees.

(N-S/E-W)

Why do these changes occur alonglatitudinal gradients? Life is moreabundant and diverse in the tropics because there is higher water availabilityand solar energy. Growing season is five times as long and five times as fastin the tropics. It is not like this in temperate or polar communities becausethey repeatedly start over because of major disturbances (glaciers).

The curve shows when all otherfactors are equal, the larger the geographic area of a community, the morespecies it has. With larger areas, greater diversity of habitats is offered.Species richness increases with community area.

An ecosystem is the sum of allthe organisms living within its boundaries (biotic community) and all of theabiotic factors they interact with. It expands upon the concept of a communitybecause it relates to the relationships in a community.

Law: matter, like energy,cannot be created or destroyed. Since mass is conserved we can determine howmuch of a chemical element is lost or gained by an ecosystem over time.Ecosystems absorb energy and release heat and waste products.

a. Primary producers: the levelthat supports all others and consists of autotrophs (self-feeders). b. Primary consumers: organismsthat are in levels above primary producers. They cannot produce their own foodso they depend on the output of primary producers. They are consumers(heterotrophs) and herbivores. c. Secondary consumers: carnivores that eat herbivores are secondaryconsumers. d. Tertiary consumers :carnivores that eat other carnivores (secondary consumers). e. Detritivores/decomposers:heterotrophs- consumers that get their energy from detritus (nonliving materiallike, remains of dead organisms, feces, wood). They are eaten by secondary andtertiary consumers. They convert organic materials from all trophic levels toinorganic compounds that can be used by producers. This way, nutrients cyclethrough ecosystems.

• a. Gross primary production(GPP): total primary production (amount of light energy converted to chemicalenergy by autotrophs) in an ecosystem.
• b. Net primary production(NPP): its equal to GPP minus the energyused for respiration (R) by producers. it represents what is available toconsumers. It is usually half of the GPP.
• c. Primary productivity (R)-the energy used by primary producers for respiration.

Aquatic ecosystems

Light and nutrients contributeto it. Light: the depth of light penetration affects primary productionthroughout the photic zone of an ocean or lake.Nutrients: it is an elementthat needs to be added to increase production. When nutrient deep watercirculates to the ocean surface, there is high primary production.

They lack iron which stimulatesgrowth of cynobacteria that fix atmospheric nitrogen and the extra nitrogenincreases phytoplankton density dramatically. This lack of nutrients results in low productivity.

A limiting nutrient is anelement that must be added for production to increase. Its usually nitrogen orphosphorus.

It is the process where a lakeis nutrient-rich and supports a vast array of algae. Cynobacteria and algaegrow rapidly due to added nutrients, ultimately reducing the oxygenconcentration and clarity of the water.

It is the amount of chemicalenergy in consumer’s food that is converted to their own biomass during a timeperiod.

Production efficiency = Netsecondary production X 100/assimilation of primary production.It measures the percentage of energystored in assimilated food (total energy taken in and used for growthreproduction, and respiration) that is not used for respiration.

.1 % can flow all the way to atertiary consumer. 10 % is lost per trophic level.

The carbon cycle: carbon isimportant because it forms the framework of organic molecules essential to allorganisms.Process: photosynthesis byplants and phytoplankton removed amounts of CO2 from the atmosphere. It isequal to the amount of added to the atmosphere through cellular respiration byphytoplankton and producers and consumers, by the burning of fossil fuels, andby the release of decomposition.Volcanoes are also a source of CO2.

It is the burning of fuel. Burning of fossilfuels adds a significant amount of additional CO2 to the atmosphere.

• a. Assimilation : the totalenergy taken in and used for growth. Plants can only take in 2 forms of N à ammonium (NH4) and nitrate (NO3). Animals can onlyuse organic forms.
• b. Nitrification: NH4 isconverted to NO3 by nitrifying bacteria.
• c. Ammonification: decomposesorganic N to NH4
• d. Nitrogen Fixation: the conversion of N2 by bacteria into formsthat can be used to synthesize nitrogenous organic compounds.

The burning of fossil fuels,deforestation, and the industrial revolution results in an increase of CO2. Itsincreased 40%The burning of fossil fuelsincreases CO2 levels, which increases the global temperature. This is globalwarming warms up the arctic and melts snow and ice, decreasing habitat forpolar bears, seals, and seabirds. This change in temperature also changesgeographic distribution, plant communities will change drastically because theycant stand the heat.

Industrial fertilizers,agriculture (plowing), and fossil fuel combustion is how N is added to the ecosystem. Released gases mix with water and turn into acid rain, which destroys habitats and forests.