APES unit 2

Ecological niche:

pattern of living (where it lives, ideal conditions, role in ecosystem, etc.)

generalist species

species with a broad niche, eat a variety of foods, live in different places, and tolerate a variety of conditions

specialist species

narrow niche, eat only a few foods, only inhabit one small range of conditions

keystone species

a plant or animal that plays a unique and crucial role in the way an ecosystem functions

have a significant role in determining the structure of the community.

density-independent population control factor

things/events that limit the size of a population regardless of it’s density (weather, pollution, floods, etc.)

density-dependent population control factor

the effects on the size or growth of a population vary with the density (disease, food/water, space, etc.)

ecosystem diversity

the number of different habitats available in a given area

1 of 3 ways diversity is measured

species diversity

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

1 of 3 ways diversity is measured

genetic diversity

how different the genomes (set of genes) are of the individuals in a population of a species

caused by random mutations in DNA

more of this leads to better responses to environmental stressors.

1 of 3 ways diversity is measured

species richness

the total number of different species found in an ecosystem

high r is generally a good sign of ecosystem health

species evenness

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

indicates if there are any dominant species or if its well balanced

bottleneck event

an environmental disturbance (natural disaster, human habitat destruction, etc.) that drastically reduces population size and kills organisms regardless of their genome

surviving population is smaller and because individuals died randomly, it doesn’t represent the genetic diversity of the original population

reduces genetic diversity, making it more vulnerable to future disturbances.

an example of genetic drift

inbreeding

when organisms mate with closely related family members

leads to higher chance of offspring having harmful genetic mutations because they’re getting similar genotypes from both parents

smaller populations see this more often

ecosystem resilience

the ability of an ecosystem to return to its original conditions after a major disturbance

goes up with species diversity

ecosystem services

services provided by the ecosystem that support humans (often monetarily or life-sustaining)

term coined in late 1990’s

provisioning

goods taken directly from ecosystems or made from natural resources

regulating

natural ecosystems regulate climate and air quality, reducing storm damage and healthcare cost

supporting

natural ecosystems support processes we do ourselves, making them cheaper and easier (bees pollinate crops)

cultural

money generated via recreation or scientific knowledge

anthropogenic activities

acts that disrupt the ability of ecosystems to function, which decreases the value of ecosystem services they provide

provisioning services

goods from ecosystems provided for sale, like fishing, hunting, lumber, naturally grown foods, seeds, grains, honey, or things made from natural resources, like paper, medicine, and rubber.

disrupted by: overhauling, water pollution, clearing land

regulating services

benefits from ecosystems that moderate natural conditions like climate and air quality

ex: trees store carbon dioxide through photosynthesis, reducing the rate of climate change

disrupted by: deforestation

supporting services

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

ex: wetland point roots filter pollutants, making cleaner groundwater without paying for purified water and treatment plans

disrupted by: pollinator habitat loss and filling in wetlands

cultural services

revenue from recreational activities and scientific discoveries from ecosystems.

ex: tourist parks, scientists finding medicinal formulas

disrupted by: deforestation, pollution, urbanization

island biogeography

the study of ecological relationships and community structure on islands

island

an area of land separated from alike lands with an ecosystem that is different from the ecosystems in nearby areas. they can be actual islands in water, or figurative habitat islands such as central park in new york (natural habitats surrounded by human developed land).

larger islands…

support more total species

greater ecosystem diversity

more food and habitat resources

more niches

larger population size

lower extinction rate

islands closer to the “mainland”…

support more species

easier for colonizing organisms to get to it from the mainland

more colonizing organisms = more genetic diversity in the new population

easier and more continual migration, bringing larger populations and genetic diversity

farther from the mainland = fewer species

evolution on islands

different beaks quickly evolve to fit a variety of food sources on the island

single colonizing species quickly develop into many slightly different ones to adapt to new conditions

ecological range of tolerance

species and organisms have a range of tolerance for different environmental/habitat conditions. this is usually caused by genetic biodiversity. has different ‘zones’.

optimal range

range where organisms survive, grow, and reproduce.

zone of physiological stress

range where organisms survive, but experience certain stresses such as infertility, lack of growth, decreased activity, etc.

zone of intolerance

range where the organism will die

natural disturbance

a natural event that disrupts the structure and/or function of an ecosystem (tornados, hurricanes, asteroids, forest fires, draught).

can be even greater than human disruptions, can be periodic, episodic, or random.

periodic

occurs with regular frequency (like seasons)

episodic

occasional events with irregular frequency (hurricanes, draught, fire)

random

no regular frequency (volcanoes, earthquakes, and asteroids)

natural climate change

a change in the earth’s climate caused naturally.

ex: slight changes in the earth’s orbit and tilt causing mini ice ages and warmer periods as the earth shifts slightly closer or farther from the sun.

sea levels vary as glacial ice melts and forms.

environmental change causes…

major disturbances result in widespread habitat changes or losses

migration

wildlife may migrate to a new habitat as the result of natural disruptions

genetic diversity exists because…

random DNA mutations while it’s being copies

crossovers in parent chromosomes creating new gene combos

adaptations

a new trait that increases an organism’s fitness

fitness

ability to survive and reproduce

natural selection

organisms that are better adapted to their environment survive and reproduce more offspring

organisms with adaptations reproduce and give them to their offspring, these without adaptations slowly dying off until the entire population is adapted

selective pressure/force

the environment condition that kills individuals without the adaptation

pace of evolution

the more rapidly an environment changes, the less likely a species will be able to adapt

• if the pace of change is too rapid, many species will migrate or die.

higher genetic diversity leads to faster adaptation

longer lifetime = slower evolution

primary succession

starts from bare rock in an area with no previous soil formation that hasn’t previously been colonized by plants (volcanic rock, exposed rock after glacial retreat).

(moss/lichen spores from winds grow directly on rocks by releasing acids and break them into soil (chemical weathering))

secondary succession

starts from already-established soil where a disturbance cleared out most plant life.

pioneer species are still dispersed by wind, but are plants instead. (fast-growing, tolerant of sunlight, sometimes less soil or nutrient needs).

indicator species

a plant/animal that, by presence, abundance, scarcity, or chemical composition, shows that some distinctive aspect of the character/quality of an ecosystem is present.

stages of succession

characterized by which types of plant species dominate the ecosystem. different species are adapted to different species

pioneer/early succession species

appear first when the ground is bare rock or soil.

characteristics: seeds spread via wind or animals, fast growing, tolerant of shallow soil and full sunlight, like moss or lichen for bare rock, wildflowers, raspberries, grasses/sedges.

mid-successional species

appear after pioneers have helped developed deeper soil with more nutrients with cycles of growth and death.

characteristics: relatively fast growing, larger plants that need deeper soils with more nutrients than pioneers. sun tolerant.

shrubs, bushes, fast-growing trees like aspen, cherry, or pine.

late successional or climax community species

appear last, after soil is deepened and enriched from cycles of growth and death by previous successional species

characteristics: large, slow-growing trees that tolerate shade and need deep soils for large root networks

ex: maples, oaks, other large trees