Unit 9.6 Biodiversity & Extinction

Define biodiversity

The variety of living organisms at genetic; species; and ecosystem levels.

What are the three levels of biodiversity

Genetic diversity; species diversity; and ecosystem diversity.

Define genetic diversity

The variation of alleles and genes within a species or population.

Define species diversity

The variety of different species within an ecosystem or geographical area.

Define ecosystem diversity

The variety of different habitats; communities; and ecosystems within a region.

How is biodiversity measured at the species level

By measuring species richness and species evenness.

Define species richness

The total number of different species present in an area.

Define species evenness

How evenly individuals are distributed among the different species in an area.

What does high species richness indicate

A large number of different species are present in an area.

What does high species evenness indicate

Individuals are distributed relatively equally among the different species.

Why are species richness and evenness both important

Richness measures the number of species; evenness measures how balanced their populations are; together they provide a better measure of biodiversity.

What is extinction

The permanent disappearance of a species when its last individual dies.

How many major mass extinction events have occurred on Earth

Five major mass extinction events.

What is a mass extinction

A relatively short geological period during which a large proportion of Earth's species become extinct worldwide.

What caused previous mass extinctions

Major environmental changes such as volcanic activity; asteroid impacts; climate change; and changes in sea levels.

How is the current biodiversity crisis different from previous mass extinctions

The current crisis is primarily caused by human activities rather than natural geological or astronomical events.

Define anthropogenic

Caused by human activities.

What are the major anthropogenic causes of species extinction

Habitat destruction; overexploitation; invasive species; pollution; and climate change.

What happened to the North Island giant moa

It was a large flightless bird in New Zealand that became extinct after human arrival due mainly to hunting and habitat modification.

What caused the extinction of the Caribbean monk seal

Hunting and exploitation by humans; along with disturbance and reduced food availability.

What happened to mixed dipterocarp forests in Southeast Asia

Large areas of tropical rainforest were lost through commercial logging; agricultural expansion; and conversion to palm oil plantations.

What caused the loss of temperate rainforests in the Pacific Northwest

Commercial logging; land development; and agricultural expansion caused widespread forest loss.

What is local extinction

When a species disappears from a particular geographical area but still exists elsewhere.

What is global extinction

When no individuals of a species remain anywhere on Earth.

What are direct anthropogenic causes of ecosystem loss

Deforestation; mining; construction; agriculture; and urban development.

What are indirect anthropogenic causes of ecosystem loss

Population growth; increased consumption; economic demand; and climate change.

How does human population growth contribute to biodiversity loss

More people increase demand for land; food; water; and energy; increasing habitat destruction; pollution; overexploitation; and greenhouse gas emissions.

What are three specific human activities that contribute to the biodiversity crisis

Deforestation for agriculture; overfishing; and burning fossil fuels that contribute to climate change.

What types of evidence can scientists monitor to assess a biodiversity crisis

Population sizes; species richness; species evenness; extinction rates; habitat loss; species distribution; and genetic diversity.

Why is monitoring population size important

Declining populations may indicate environmental stress and an increased risk of extinction.

What is the role of citizen scientists in monitoring biodiversity

Members of the public collect and report observations of species and ecosystems; helping scientists gather large amounts of data across different locations.

What is in situ conservation

Protecting species within their natural habitats and ecosystems.

Give examples of in situ conservation

National parks; nature reserves; and marine protected areas.

What is ex situ conservation

Protecting species outside their natural habitats under human care or controlled conditions.

Give examples of ex situ conservation

Zoos; botanical gardens; seed banks; and captive breeding programs.

What is an advantage of in situ conservation

It protects entire ecosystems and multiple species while maintaining natural interactions and evolutionary processes.

What is an advantage of ex situ conservation

It provides controlled protection and breeding opportunities for species that may be threatened in the wild.

Compare in situ and ex situ conservation

In situ protects organisms in their natural habitats; ex situ protects organisms outside their natural habitats.

Define rewilding

Restoring ecosystems by allowing natural processes to recover; sometimes through reintroducing native species.

What is the EDGE of Existence program

A conservation program that prioritizes Evolutionarily Distinct and Globally Endangered species.

How does the EDGE program choose species for conservation

It prioritizes species with unique evolutionary histories and high extinction risk.

Why is the EDGE program important for biodiversity

It protects species that represent unique evolutionary history and whose extinction would eliminate irreplaceable genetic diversity.