AP Environmental — The Living World: Biodiversity

Unit 2

Ecosystem Diversity

The number of different habitats available in a given area

Species Diversity

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

Genetic Diversity

How different the genes are of individuals within a population

• Exists due to random mutations in copying DNA, leading to new gene combinations and new traits in offspring

Species Richness

The total number of different species found in an ecosystem

• Good sign of ecosystem health

Bottleneck Event

A disturbance that drastically reduces population size and kills organisms regardless of their genome

• Since surviving population is smaller, it doesn’t represent genetic diversity of the original population

• Population is more vulnerable to future disturbances because it’s less diverse genetically

Inbreeding Depression

Organisms mate with closely related family members

• Leads to higher chances of harmful genetic mutations as they’re getting similar genomes from parents

• Smaller populations are more likely to experience this

• If all offsprings have the same parents, they reduce gene pool since they’re half similar genes with others

Species Evenness

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

Ecosystem Resilience

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

Ecosystem Services

Goods that come from natural resources/services/functions that ecosystems carryo out that have economical/financial value

Provisioning

Goods taken directly from ecosystems or made from natural resources

Disruptive examples:

• Overharvesting

• Water pollution

• Clearing land

Regulation

Natural ecosystems regulate climate/air quality, reducing storm damage and healthcare costs

Disruptive examples:

• Deforestation

Supporting

Natural Ecosystems support processes we do ourselves, making them easier and cheaper 

Disruptive examples:

• Pollinator habitat loss

• Filling wetlands for development

Cultural

Money generated by recreation (parks, camping, tours, or scientific knowledge)

Disruptive examples:

• Deforestation

• Pollution

• Urbanization

Island Biogeography

Study of ecological relationships and community structure on islands

Island Area

• The larger the land, the greater the ecosystem diversity

• Greater diversity leads to more food and habitat resourcces

• More niches/roles organisms can have in the ecosystem

• Lower extinction rates

Island Isolation

• Easier for colonizing organisms if closer to mainland

• More colonizing leads to genetic diversity

• Continual migration brings more diversity and population size

Ecological Range of Tolerance

The range of conditions such as temperature, salinity, pH, or sunlight an organism can endure before death/injury results

• It exists for all different environmental conditions of their habitats due to genetic diversity

Limiting Factor

The factor most likely to regulate population growth

Optimal Range

Where organisms survive, grow, and reproduce

Zone of Physiological Stress

Organisms survive, but experience some stress like infertility, lack of growth, decreased activity, etc.

Zone of Intolerance

Organisms will die

Periodic Disturbance

Occurs with regular frequency

• Seasons

• Tides

Episodic Disturbance

Occasional events with irregular frequency

• Natural disasters like hurricanes or tornadoes

Random Disturbance

No regular frequency

• Volcanic eruptions

• Tsunamis

• Fires

Diversity Hotspot

A place with a lot of biodiversity because of the sun, soil, temperature, and rain

Speciation

Process, through evolution, of making new species

Habitat Disruption

Major environmental disturbances result in widespread habitat changes/loss

Migration

Wildlife may do this as a result of natural disruptions, following wherever best accommodates their optimal range

Genetic Adaptation

The process where a population's inherited traits change over generations in response to environmental pressures, leading to improved survival and reproduction

Natural Selection

Organisms are better adapted to their environment to survive and produce more offspring

Selective Force/Pressure

The environmental condition that kills individuals without adaptations

If environmental change is rapid…

Many species may migrate out/die off

If environmental change is gradual…

There’s more time for adaptations

If genetic diversity is high…

The better species can adapt with good mutations

If genetic diversity is low…

All animals are susceptible to being wiped out

If the lifespan is long…

Slow evolution rate

If the lifespan is short/fast…

Fast evolution rate

Primary Succession

• 100-200 years ago

• Starts on barren rock

• Pioneer species begin to develop and becomes the base of soil

  • Lichens

  • Moss

• Has low nutrient needs and doesn’t require soil

Secondary Succession

• 50-100 years

• Begins after a disturbance

• After the destruction of the area, only soil remains

Pioneer Species

The first species to arrive

Foundation Species

Not necessarily the first, but gives foundation for ecosystems

Specialist/Niche Species

Smaller range of tolerance or narrower ecological niche makes them more prone to extinction

• Specific food requirements

• Less ability to adapt to new conditions

• Less nutrient efficiencies

Generalist

Larger range of tolerance or broader niche makes them less prone to extinction and more likely to be invasive

• Broad food requirements

• High adaptability

Endemic Species

Native species that are specific to one/few places and are highly specialist