APES UNIT 2 EXAM

genetic diversity

variability in genetic makeup among individuals in a pop. if too few DNA differations, there will be a chance for genetic bottleneck and extinction

genetic bottleneck

when a population is greatly reduced in size, limiting the genetic diversity of the species.

causes of bottleneck

mass hunting, natural disaster, loss of food, intro of non-native species

species diversity

number of species in area

high biodiversity area

rainforest

low biodiversity area

desert

anthropogenic

originates from human activity

Ecological Services

Natural things.
Provisioning: Ecosystem provides things “stuff” (matter) Ex: water, lumber

Regulating: BIG PICTURE, greenhouse gas regulation, water quality, air quality

Supporting: Without these, others could not exist. EX: Photosynthesis, nutrient cycling, soil formation

Cultural: Aesthetic beauty, religious purposes

Ecotone

A transitional zone where 2+ communities meet high biodiversity (ex: Intertidal zones)

what do you notice from this graph

there is more diversity with medium stress

factors that determine species diversity

-Habitat stress

-Available niches

-Dominance of species

-Geological history

true or false: does genetic diversity make populations more resiliant to env. disturbances

true

high species richness means

high resiliance

how do lichen and mosses intiate primary succession

secrete acids onto rocks, leading to chem weathering

hardiness

species can survive in harsh conditions

climax species / climax community

when this ecosystem stops experiencing sporadic change and instead reaches stability. This means that, under the current climate conditions, little to no changes are occurring. Most diagrams depict this as a forest, though the Sahara Desert has remained unchanged for almost five thousand years.

If conditions change, the ——- ——- will change and succession will begin again.

species

Considered separate if they cannot interbreed

Same ——————- create viable offspring

succession

communities change over time

primary succession

Starts w/ new land.

Species land on new material and colonize (pioneer community). Bare rock→ Mosses and lichen form soil → Soil → soil thickens shrubs grow

examples of lichen getting to new land

Can be N fixers - Put Nitrate into soil for other plants to grow! Can also measure air poll.

secondary succession

Starts w/ already formed land.

Species land on disturbed material.

as community complexity increases..

more species are able to live in community

genetic diversity

the range of different inherited traits within a species. The more ——- a species has, the more resilient it is; it has more “options” for response/adaptation to occur if the environment changes

species diversity

–the number of different species present in an ecosystem and relative abundance of each of those species (takes into account species richness and species evenness)

The more —— there is; the more resilient that ecosystem is to changes

habitat diversity

–the range of habitats where different species live (habitat→the natural home or environment of an animal, plant, or other organism)

When ——- are lost, specialist species are lost followed by generalist species and then species that require a lot of territory (space) are lost

Habitat loss

the number one cause of organism extinction!!!

species richness

# of different species

species evenness

describes distribution of abundance (total number) across the species; it is high when all species have a similar number

generalists categories

broad niche, adaptable to many environments. diet, not picky, variety. location, can be found around world. range of tolerance, high “go with flow” tolerant to changes.

specialist categories

narrow niche, not adaptable to change in environment. limited diet. location, found in specific habitats. range of tolerance is low, “thats NOT how we do it.” highly sensitive to change, the pop declines to change

examples of generalists

Raccoons, rats, mice, cockroaches, coyotes, whitetail deer, brown rats, horseshoe crab

specialists

Panda, river otter, owls, koala, sword-billed hummingbird, venus flytrap

alleles

alternative forms of a gene found at the same place on a chromosome; arise due to mutations

-Different ——-⇒variation of traits

Example: petal color in plants

bottleneck effect

-Occurs when a population is sharply reduced in size by a natural disaster (ex: earthquakes, floods, fires)

founder effect

A small group splits off from the main population to found a colony (ex: islands, habitats cut off due to urbanization)

natural selection

there is a struggle for existence among organisms, there is physical and behavorial variation in living organisms (even within species level), common descent/descent with modication as every living species has descended with changes from other species over time.

why can'‘t humans evolve to cope with our new enviornmental conditions

genes for new traits have to already be present in a population’s gene pool through a random mutation. human gen times are too long to keep up with rapid conditions.

islands that are larger and closer to the mainland have…

higher species richness

edge effect

The phenomenon where selective logging will cause caps in the canopy, and the —- slowly degrade bc of wind, invasion, and sunlight, leading to habitat fragmentation, and species being more susceptible to viable populations

Why is habitat fragmentation bad

it cuts species off from larger populations thus causing inability to support viable populations.

provisioning ecosystem service

products that are directly provided

regulating ecosystem service

maintaining processes

cultural ecosystem service

nonmaterial benefits, habits, or traditions

supporting ecosystem services

allows for other services to exist

Simpson’s Diversity Index

D= D = Σn_i(n_i-1)  /  N(N-1)

where:

• n_i: The number of organisms that belong to species i

• N: The total number of organisms
  
  Measurements range from 0 to 1, with 1 being highest richnessas

as extinction increases …

immigration of species decreases

larger islands closer to land have what rate of immigration

higher rate of immigration bc of their proximity to other larger ecosystem

what is ideal point btwn immigration and extinction for an island

point of equlibrium

maximum species diversity is reached when

an ecosystem experiences an intermediate level of disturbance. It is because both early and late succession species are able to survive at the same time.

reproductive isolation

when two populations are no longer able to reproduce with each other.

allopatric speciation

If there is a physical barrier between them (a road cutting through a forest. 2 populations are forced to avoid reproduction.

sympatric seciation

if the populations are in the same area but do not reproduce. the populations coexist and do not reproduce.

fauna

vegetation being replaced over time, becoming larger as long as succession progresses. shown in many diagrams

keystone species

depended upon by other species in the ecosystem such that if it were removed, the ecosystem would undergo dramatic changes. disproportionate in size, meaning that they have relatively low population density for how extremely important their effect on their ecosystem is

indicator species

one that reflects the health of its ecosystem- if it dies or has low population density, the ecosystem’s health is poor

where do specialist species thrive

in habitats that remain constant

where do generalist species thrive

in habitats that are changing

pioneer member

pioneer members relating to ecological succession

s

members moving into bare, uninhabited areas, then colonizing them as they are a hardy, fast-growing species. prepare the environment for more complex species to thrive.