apes unit 2

biodiversity

the diversity of lifeforms in an environment

is biodiversity critical to the functioning of ecosystems?

yes!

meta study

study of studies

more fungi = ?

more decomposition = more phosphorus made available for plants = more growth

species evenness

measure of # of individuals

species richness

number of different species in a given area of an ecosystem

genetic diversity

a measure of the genetic variation among individuals in a population

do large populations have a high amount of genetic diversity?

yes!

genetic diversity example

white tailed deer lives throughout NA, CA, and SA & lives in different habitats across the continents and have evolved differently across climates.

population bottleneck

large population declines in #, the amount of genetic diversity carried by the surviving population is greatly reduced

what happens when a population rebounds after a bottleneck?

if the population rebounds, it can still have a low amount of genetic diversity

a species is….

a group of organisms that is distinct from other groups in morphology, behavior, or biochemical properties.

species diversity is…

the # of species in a region of in a particular ecosystem

habitat diversity is…

the variety of habitats that exist in a given ecosystem

specialists

they only live in specific conditions

generalists

they can live under a range of conditions

ecosystem diversity is..

the variety of ecosystems that exist in a given region

high genetic diversity…

benefits the long term survival of populations because they are better able to respond to environmental change compared to populations with low genetic diversity.

low genetic diversity,,,

the population is more susceptible to decline due to disease.

species diversity being higher =

more productivity & resilience, greater primary productivity that can resist impact or quickly recover from disasters.

diverse species =

greater stability of other species

lack of diverse species =

usually an indicator of an environmental problem

biodiversity is quantifiable in…

terms of species richness & evenness

how many species discovered a year?

15-18k

ecosystem services

processes by which life supporting resources such as clean water, timber, fisheries, & agricultural crops are produced.

how do ecosystem services benefit people?

directly (by providing food or water) or indirectly (providing a diversity of conditions, nutrients, and species making the ecosystem healthier)

provisions

an ecosystem service. goods produced by ecosystems that humans can use directly like lumber, food, crops, etc.

regulating services

an ecosystem service. natural ecosystems help to regulate environmental conditions. ex: humans add carbon to the atmosphere, natural ecosystems remove some of it.

support systems

an ecosystem service. natural ecosystems provide numerous support services that would be extremely costly for humans to generate. ex: pollination of food crops would be worth 3 bi

cultural services

an ecosystem service. ecosystems provide cultural or aesthetic benefits to many people. ex: intellectual gain, aesthetic satisfaction.

monetary value of ecosystem services

ecosystem services can’t always be quantified, but are estimated to be worth over 125 trillion per year.

food production is increasing because..

new varieties of crops, increased irrigation, & synthetic fixed nitrogen fertilizers. increasing faster than humans can consume it.

aquaculture

the capture of wild animals from the ocean, and the farming of fish, shellfish, and seaweed. growth of aquaculture has led to loss of natural coastal habitats in tropical countries.

water availibility

freshwater is being used faster than it can be replenished, biggest demand for it is agriculture which pollutes it, available water doesn’t always mean clean water.

pollination services

provide a critical ecosystem support service for humans. this service is declining which is concerning for the conservation of biodiversity & future crop production.

island biogeography

began with the recognition that larger islands contained more species than smaller islands.

species-area curve

a description of how the number of species on an island increases with the area of the island.

relationship between island area (A) and species richness (S)

logS = z log A + log c (z is slope, log x is constant that represents the y-int)

effects on island size on ecological relationships

smaller islands don’t/can’t support large predators.

the # of species on islands depends on..

rates of colonization & extinction. distance between a habitat and a source of colonizing species is a second factor that affects species richness.

large island extinction rate

lower rate.

natural effect of island distance

ex: new guinea (large island & large source of colonizing bird species)’s nearby islands had more bird species than ones far from New Guinea.

ecological tolerance determines…

where individuals & species can live. every individual has an environment where they perform well, so each individual has a range of ecological tolerance

ecological tolerance

the suite of abiotic conditions under which a species can survive, grow & reproduce.

fundamental niche

where species could live. establishes they abiotic limits for the persistence of a species.

realized niche

where species actually lives.

changes in environmental conditions can cause…

changes in species distribution due to climate changing & ecological tolerance.

environmental change beyond a species’ ecological tolerance can cause…

species extinctions! 99% of species that have ever lived on earth are extinct.

mass extinction

large #’s of species went extinct over a short period of time.

natural disruption range

from temp drops bringing a cold front to human activities changing the climate.

periodic disruptions

occur regularly like night & day, or monthly.

random disruptions

no regular pattern, like hurricanes or volcanic eruptions. rarely hit the same part of the world twice.

episodic disruptions

regularly, like cycles of high rain & low rain every 5-10 yrs.

short duration disruptions

also have a small spacial extent. geologic changes take much longer.

ecosystem resistance

a measure of how much a disruption can affect the flows of energy and matter.

ecosystem resilience

the rate at which an ecosystem returns to its original state after a disruption occurs. depends on specific interactions of the biogeochemical & hydrologic cycles.

how to measure climate & sea level changes

indirect measures like changes in species composition of organisms, and chemical analyses of air bubbles formed in ice.

how to measure changing species compositions

common biological measurement is the change in species composition of s group of small protists (foraminifera) which are tiny marine organisms with shells that cannot decompose.

how to measure earth’s changing sea levels

indirectly determining changes because direct measurement only goes back to the 1800s.

disruptions can cause..

large habitat changes & animal migrations. habitats adapt to constant disruptions, and disasters can be selective as to which species they harm

seasonal disruptions favoring migrations

seasonal changes are disruptions that prompt animals to migrate in search of food.

allele

ex: what your house looks like, or what you look like.

gene

ex: address of your house. specific place on your dna. where the allele is located.

microevolution

evolution at the population level. ex: evolution of different varieties of apples

macroevolutions

when genetic changes give rise to new species.

phenotype

traits that an individual exhibits

genotype

the blueprint for the complete set of traits

genetic variation can be caused by..

mutations or recombination (when chromosomes stick together and brings together alleles to make a combination)

evolution by artificial selection

used to breed animals and plants, produced different breeds or species

evolution by natural selection

a natural mechanism where the environment determines which individuals survive & reproduce

key ideas of darwins theory

individuals produce, an excess of offspring, not all offspring can survive, individuals differ in their traits, differences in traits can be passed on from parents to offspring, differences in traits are associated with differences in the ability to survive ad reproduce.

natural selection favors..

an individuals fitness. traits that improve an individuals fitness are called adaptations.

evolution by random processes

these processes alter the genetic composition of a population overtime, but don’t alter the fitness of an individual

mutation

if a random mutation isn’t lethal it can add to the genetic variation of a population. larger population = more opportunities for mutations. mutation over time is called evolution.

gene flow

when individual move from one population to another & alter the genetic composition of both populations. can bring genetic variation to a population that lacks it.

genetic drift

a change in the genetic composition of a population over time as a result of random mating. can cause the elimination of some of the individuals that carry unique traits because they didn’t find a mate in a given year.

bottleneck effect

a drastic reduction in the size of a population that reduces genetic variation. can occur because of habitat loss, harvesting by humans, or changes in the environment.

founder’s effect

when a small group of a species separates from the greater population from the greater population, and give rise a population that has a genetic composition that is very different from the greater population that the founders/colonizers came from.

allopatric speciation

occurs through geographic isolation, which means the physical separation of a group of individuals from others of the same species.

sympatric speciation

the evolution of one species into the two species without any geographic isolation. occurs through polyploidy (where the number of chromosome sets increases). once polyploidy occurs, they are reproductively separated from diploid organisms. can still live in the same place.

ecological succession

the predictable replacement of one group of species by another group of species over time.

primary succession

when succession begins with bare rock and no soil.

secondary succession

occurs in areas that have been disturbed but have not lost their soil. follows events like forest fires or hurricanes. begins with rapid colonization of the disturbed area.

succession in streams

occurs in streams that experience major floods. fast moving water can displace rocks and eliminate algae and invertebrate animals.

succession in shallow freshwater lakes & ponds

glaciers carve out a lake/pond basin, leaving it full of sediments and vegetation algae and plants colonize it over time, and the erosion of rocks and soil fills the basin with organic matter make it shallow. over time, it fills completely and becomes a terrestrial habitat.

succession affects..

species richness, and community biomass and productivity by initially increasing it. ecological succession causes an increase in species richness over time, so it also causes an increase in biomass over time.

keystone species

a species that is not very abundant but has large effects on an ecological community. ex: beavers play a critical role in forests by building dams that convert narrow streams into large ponds, creating habitats for pond-adapted plants and animals.

indicator species

a species used to characterize when ecosystems have been negatively impacted by humans or when ecosystems are rebounding from some harmful impact.