APES Unit 2

biodiversity

diversity of life forms in an ecosystem

3 different ways to measure biodiversity

ecosystem/habitat, species, genetic diversity

higher biodiversity =

higher ecosystem/population health

habitat diversity

the different kinds of habitats in a given unit area

species diversity

the number of different species in an ecosystem and the balance or evenness of the population sizes of all species in the ecosystem

genetic diversity

how different the genes are of individuals within a population

species richness

total number of different species found in an ecosystem

species evenness

how all of the individual organisms in an ecosystem are balanced between the different species

evenness indicates

if there are one or two dominant species, or if population sizes are well balanced

genetic diversity occurs because

random mutations in copying of DNA, recombination of chromosomes in sex cells of parents

higher genetic diversity =

better the population can respond to environmental stressors

Bottleneck event

an environmental disturbance that drastically reduces the population size and kills organisms regardless of their genome

inbreeding depression

genetically similar parents mate and produce inferior offspring

ecosystem resilience

an ecosystem's ability to recover from disturbance

ecosystem services

goods that come from natural resources or services/functions that ecosystems carry out that have measurable economic/financial value to humans

humans disrupt ecosystem services

Human activities disrupt the ability of ecosystems to function, which decreases the value of ecosystem services they provide

provisioning services

goods/products directly provided to humans for sale/use by ecosystems

provisioning services are disrupted by

overharvesting, water pollution, clearing land for ag/urbanization

regulating services

benefit provided by ecosystem processes that moderate natural conditions like climate and air quality.

regulating services are disrupted by

deforestation

supporting services

natural ecosystems support processes we do ourselves, making them less costly and easier for us

supporting services are disrupted by

pollinator habitat loss and filling in wetlands for development

cultural services

revenue from recreational activities and profits made from scientific discoveries made in ecosystems.

cultural services are disrupted by

deforestation, pollution, urbanization

island biogeography

study of ecological relationships and community structure on islands

rules of biogeography

larger islands support more total species, islands closer to the "mainland" support more species

resilience

the rate at which an ecosystem returns to its original state after a disturbance

resistance

how well an ecosystem resists a disturbance

niche

An organism's particular role in an ecosystem, or how it makes its living.

larger islands

higher ecosystem diversity, more available niches, larger population size, lower extinction rate.

islands closer to mainland

higher species richness

adaptive radiation

An evolutionary pattern in which many species evolve from a single ancestral species to use different resources and reduce competition

evolution is quicker on islands because

more pressure for species to adapt to narrower niches

range of tolerance

the limits to the abiotic conditions that a species can tolerate

range of tolerance conditions

sunlight, salinity, pH, temperature

species have different range of tolerance than individuals

genetic diversity

optimal range

range where organisms can survive, grow, and reproduce

zone of physiological stress

range where organisms survive, but experience some stress

physiological stress examples

infertility, lack of growth, decreased activity

zone of intolerance

zone where organisms cannot survive

natural disturbance

A natural event that disrupts the structure and or function of an ecosystem

why genetic diversity exists

crossing over and random mutations in the copying of DNA

natural selection

organisms better adapted to their environment tend to survive and produce more offspring

selective pressure

the environmental conditions that kills individuals without the advantageous adaptation

the more rapid an environment changes,

the less likely the species in the environment will be able to adapt to those changes.

ecological sucession

a series of predictable stages of growth that a forest goes through

primary succession

ecological succession begins in a lifeless area with no soil, on bare rock

secondary succession

succession that starts from already established soil in an area where a natural disturbance cleared out the majority of plant life

determines ecological succession stages

plant life

pioneer species / early succession species

species that appear first when ground is bare rock or bare soil

characteristics of pioneer species

seeds spread by wind or animals, fast growing, tolerant of shallow soil and full sunlight

mid-succession species

appear after pioneer species have helped develop deeper soil with more nutrients by their cycles of growth/death

characteristics of mid-succession species

fast growing, larger plants, need deeper soil with more nutrients than pioneer species, sun tolerant

late successional/climax community species

appear last, after soil is deepened and enriched with nutrients by cycles of growth and death by early & mid successional species

characteristics of late successional species

large, slow growing trees that are tolerant of shade and require deep soils for large root networks