Define biodiversity .

Biodiversity is the variation of genes, species, and habitats in a region.

What are three examples of measures used to assess biodiversity?

The genetic variation within each species The number of different species and the relative abundance of each species The number and range of different ecosystems and habitats

Ecosystems with more components and greater biodiversity are more to environmental change.

Ecosystems with more components and greater biodiversity are more resilient to environmental change.

True or False? Natural and artificial ecosystems with fewer component parts and little diversity are often less resilient to environmental change.

True. With fewer parts and little diversity, an ecosystem may be unable to adapt, making it more vulnerable to disturbance and potential collapse.

What can happen to an ecosystem that has too few component parts when the environment changes?

It may be unable to adapt, resulting in: loss of species instability and potential ecosystem collapse disruption to feeding relationships in food chains and webs reduced nutrient cycling and productivity

Which factors contribute to maintaining the diversity of an ecosystem?

Essential biotic and abiotic factors Producers , which form the base of all food chains Keystone species

Why are producers an essential component of an ecosystem?

Producers form the base of all food chains , supplying the energy on which every other organism in the ecosystem depends.

Define keystone species .

Keystone species are those that have a disproportionate effect on the structure and function of their ecosystem relative to their abundance.

True or False? The effect of a keystone species on its ecosystem is proportional to how abundant it is.

False. The effects of a keystone species are disproportionate relative to their abundance; when they are removed, the ecosystem often collapses.

The removal of a keystone species can cause loss of other species and possible ecosystem .

The removal of a keystone species can cause loss of other species and possible ecosystem collapse .

How do sea otters act as a keystone species in Pacific Northwest kelp forests?

Sea otters help control the population of sea urchins . Without this control, sea urchins overgraze the kelp, leaving no food or habitat for other species.

How do elephants act as a keystone species?

Elephants consume shrubs and small trees, maintaining grassland and preventing the growth of larger plants. This preserves food for grazers such as zebras, which in turn supports predators such as lions.

Beavers slow the flow of running water, creating a habitat that supports many other species.

Beavers slow the flow of running water, creating a wetland habitat that supports many other species.

How does protecting keystone species benefit an ecosystem?

It maintains the stability of the ecosystem, which in turn benefits the many other species that depend on it.

Adaptation is a genetic variation, favored by selection, that manifests as a trait providing an advantage to an organism in a particular environment.

Define heterozygote advantage .

Heterozygote advantage is when the heterozygous genotype has a higher relative fitness than either the homozygous dominant or homozygous recessive genotype.

True or False? Mutations are directed by specific environmental pressures.

False. Mutations occur randomly during DNA replication and are not directed by environmental pressures. Selection then acts on the variation that already exists.

How does heterozygote advantage maintain the sickle cell allele in regions where malaria is common?

Hb A /Hb S heterozygotes are largely symptom-free and gain resistance to malaria , giving them higher fitness than either homozygote, so the sickle cell allele is kept in the population.

Define invasive species .

Invasive species are species that move into an ecosystem where they were not previously present, usually introduced through human activity.

Why can an invasive species undergo uncontrolled population growth in a new ecosystem?

It can exploit a new niche because it often lacks natural predators or competitors , allowing it to outcompete native species for resources.

An invasive species may be introduced , for example as a biological control for pests, or unintentionally through the global transport of goods.

An invasive species may be introduced intentionally , for example as a biological control for pests, or unintentionally through the global transport of goods.

Define biomagnification .

Biomagnification is the increase in concentration of persistent (non-biodegradable) pollutants with ascending trophic level through a food chain.

True or False? Bioaccumulation is the increase in pollutant concentration between trophic levels.

False. Bioaccumulation is the build-up of pollutants within a single organism or trophic level. The increase in concentration between trophic levels is biomagnification .

Outline how eutrophication leads to the death of aquatic organisms.

Excess nitrates and phosphates run off into the water, causing an algal bloom The algae block sunlight, so submerged plants die Decomposers break down the dead material, and their aerobic respiration uses up dissolved oxygen Falling oxygen levels kill fish and other organisms, creating dead zones

Eutrophication is the of a water body, usually by nitrates and phosphates from fertilizers.

Eutrophication is the nutrient enrichment of a water body, usually by nitrates and phosphates from fertilizers.

How can geological and meteorological events change ecosystems?

Events such as El Niño , continental drift , and meteor impacts create abiotic and biotic changes , leading to shifts in habitat, species distribution, and ecosystem dynamics.

What ecosystem change is linked to the Chicxulub meteor impact around 66 million years ago?

It likely caused the mass extinction that ended the age of the dinosaurs; the new abiotic conditions then allowed the evolution of new species and ecosystems.

True or False? El Niño events are always caused by human activity.

False. El Niño is a natural climate event occurring every 2–7 years, although human activity may accelerate its effects.

AP®BiologyCollege BoardFlashcardsUnit 8: EcologyBiodiversity & Disruptions to Ecosystems

Biodiversity & Disruptions to Ecosystems (College Board AP® Biology): Flashcards

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FrontBiodiversity
Define biodiversity.
FrontBiodiversity
What are three examples of measures used to assess biodiversity?
BackBiodiversity
The genetic variation within each species
The number of different species and the relative abundance of each species
The number and range of different ecosystems and habitats

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Cards in this collection (28)

Define biodiversity.
Biodiversity is the variation of genes, species, and habitats in a region.
What are three examples of measures used to assess biodiversity?
- The genetic variation within each species
- The number of different species and the relative abundance of each species
- The number and range of different ecosystems and habitats
Ecosystems with more components and greater biodiversity are more to environmental change.
Ecosystems with more components and greater biodiversity are more resilient to environmental change.
True or False?
Natural and artificial ecosystems with fewer component parts and little diversity are often less resilient to environmental change.
True.
With fewer parts and little diversity, an ecosystem may be unable to adapt, making it more vulnerable to disturbance and potential collapse.
What can happen to an ecosystem that has too few component parts when the environment changes?
It may be unable to adapt, resulting in:
- loss of species
- instability and potential ecosystem collapse
- disruption to feeding relationships in food chains and webs
- reduced nutrient cycling and productivity
Which factors contribute to maintaining the diversity of an ecosystem?
- Essential biotic and abiotic factors
- Producers, which form the base of all food chains
- Keystone species
Why are producers an essential component of an ecosystem?
Producers form the base of all food chains, supplying the energy on which every other organism in the ecosystem depends.
Define keystone species.
Keystone species are those that have a disproportionate effect on the structure and function of their ecosystem relative to their abundance.
True or False?
The effect of a keystone species on its ecosystem is proportional to how abundant it is.
False.
The effects of a keystone species are disproportionate relative to their abundance; when they are removed, the ecosystem often collapses.
The removal of a keystone species can cause loss of other species and possible ecosystem .
The removal of a keystone species can cause loss of other species and possible ecosystem collapse.
How do sea otters act as a keystone species in Pacific Northwest kelp forests?
Sea otters help control the population of sea urchins. Without this control, sea urchins overgraze the kelp, leaving no food or habitat for other species.
How do elephants act as a keystone species?
Elephants consume shrubs and small trees, maintaining grassland and preventing the growth of larger plants. This preserves food for grazers such as zebras, which in turn supports predators such as lions.
Beavers slow the flow of running water, creating a habitat that supports many other species.
Beavers slow the flow of running water, creating a wetland habitat that supports many other species.
How does protecting keystone species benefit an ecosystem?
It maintains the stability of the ecosystem, which in turn benefits the many other species that depend on it.
Define adaptation.
Adaptation is a genetic variation, favored by selection, that manifests as a trait providing an advantage to an organism in a particular environment.
Define heterozygote advantage.
Heterozygote advantage is when the heterozygous genotype has a higher relative fitness than either the homozygous dominant or homozygous recessive genotype.
True or False?
Mutations are directed by specific environmental pressures.
False.
Mutations occur randomly during DNA replication and are not directed by environmental pressures. Selection then acts on the variation that already exists.
How does heterozygote advantage maintain the sickle cell allele in regions where malaria is common?
Hb^A/Hb^S heterozygotes are largely symptom-free and gain resistance to malaria, giving them higher fitness than either homozygote, so the sickle cell allele is kept in the population.
Define invasive species.
Invasive species are species that move into an ecosystem where they were not previously present, usually introduced through human activity.
Why can an invasive species undergo uncontrolled population growth in a new ecosystem?
It can exploit a new niche because it often lacks natural predators or competitors, allowing it to outcompete native species for resources.
An invasive species may be introduced , for example as a biological control for pests, or unintentionally through the global transport of goods.
An invasive species may be introduced intentionally, for example as a biological control for pests, or unintentionally through the global transport of goods.
Define biomagnification.
Biomagnification is the increase in concentration of persistent (non-biodegradable) pollutants with ascending trophic level through a food chain.
True or False?
Bioaccumulation is the increase in pollutant concentration between trophic levels.
False.
Bioaccumulation is the build-up of pollutants within a single organism or trophic level. The increase in concentration between trophic levels is biomagnification.
Outline how eutrophication leads to the death of aquatic organisms.
- Excess nitrates and phosphates run off into the water, causing an algal bloom
- The algae block sunlight, so submerged plants die
- Decomposers break down the dead material, and their aerobic respiration uses up dissolved oxygen
- Falling oxygen levels kill fish and other organisms, creating dead zones
Eutrophication is the of a water body, usually by nitrates and phosphates from fertilizers.
Eutrophication is the nutrient enrichment of a water body, usually by nitrates and phosphates from fertilizers.
How can geological and meteorological events change ecosystems?
Events such as El Niño, continental drift, and meteor impacts create abiotic and biotic changes, leading to shifts in habitat, species distribution, and ecosystem dynamics.
What ecosystem change is linked to the Chicxulub meteor impact around 66 million years ago?
It likely caused the mass extinction that ended the age of the dinosaurs; the new abiotic conditions then allowed the evolution of new species and ecosystems.
True or False?
El Niño events are always caused by human activity.
False.
El Niño is a natural climate event occurring every 2–7 years, although human activity may accelerate its effects.

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