APEs Unit 2 Review

Keystone species

species that are not abundant but have large effects on the ecological community (ex: beavers - make dams, otters - protect kelp forests and control mussel population)

Indicator species

species that can demonstrate a particular characteristic of an ecosystem, can be important for suggesting presense of harmful species

Bottleneck effect

when a population shrinks suddenly due to an outside cause. decreases genetic variation

Generalist species

species that can tolerate a very wide range of abiotic or biotic conditions

Scales of biodiversity

Genetic - measure of genetic variation among individuals in a population

Species - number of species in a region or in a particular ecosystem

Habitat - variety of habitats that exist in a given ecosystem

Ecosystem - variety of ecosystems that exist in a given region

Specialist species

species that only live under a narrow range of biotic or abiotic conditions (ex: koalas)

Species richness

number of different species in a given area

Ecosystem services

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

Species eveness

relative proportion of individuals within the given species in a given area (an ecosystem has high species evenness if its species are all represented by similar numbers of individuals)

Types of ecosystem services

Provisional - goods produced by ecosystems that humans can use directly (ex: lumber, food crops, medicine, rubber, furs, etc.)

Regulating - ecosystems regulate environmental conditions (ex: trees remove carbon from the atmosphere, regulate nutrient and water cycle)

Supporting - ecosystems provide support services that would be costly for humans to generate (ex: pollination, natural pest control, filters/purify water)

Cultural - ecosystems provide cultural/aesthetic benefits (ex: national parks, inspires art, religious value)

Anthropogenic activities can disrupt ecosystem services.

Island biogeography

study of ecological relationships and distribution of organisms on islands, and of those organisms’ community structures

Theory of island biogeography

many island species have evolved to be specialists because of the limited resources, islands that are large and closest to the mainland tend to have the highest biodiversity

Ecological tolerance

range of conditions that an organism can endure before injury or death results, can apply to individuals and species

Primary succession

ecological succession occurring on surfaces with bare rock and no soil, pioneer species are algae and lichen, occurs after glacial retreat, volcanic eruption, or on an abandoned parking lot

Environmental disruptions

Periodic - occur regularly, such as cycles of day and night or daily/monthly cycles of moon’s effect on ocean tides

Episodic - somewhat regular, such as cycles of high/low rain

Random - have no regular pattern, such as volcanic eruptions or hurricanes

Resistance

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

Resilience

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

Secondary succession

succession of plant life that occurs in areas that have been disturbed but have not lost their soil, occurs after forest fires or hurricanes, removes vegetation but leaves soil mostly intact

Climax community

historically described as the final stage of succession

Ecological succession

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

Intermediate disturbance hypothesis

ecosystems experiencing intermediate levels of disturbances will favor a higher level of diversity of species than those with high or low disturbance levels