CH 7.2 Extinction & Biodiversity Loss

How did studies of oceanic islands help scientists understand the effect of habitat fragmentation on species diversity?

10 Studies of oceanic islands revealed that island size is related to species diversity. The larger the island, the greater the species diversity. This pattern holds with habitat fragments, or "islands," that are found within an "ocean" of unsuitable habitat.

What factors determine whether nonnative species are considered invasive?

12 If nonnative species populations increase rapidly and they spread and displace native species, they they are considered invasive.

Many protected animals are lost to poaching. What is a main motivation behind poaching?

14 Many protected animals or animal parts can be sold illegally for large sums of money.

How do the effects of climate change differ from the effects of habitat alteration, invasive species, overharvesting, and pollution?

6 Climate change affects all of Earth, while habitat alteration, invasive species, overharvesting, and pollution have more local effects, only affecting the parts of Earth where they are occurring.

A conservation plan could proceed with a single 20-square kilometer habitat preserve or with two habitat preserves, measuring a total of 20 square kilometers combined. Which preserve format would support more species? Explain.

7 The single habitat would support more species. The larger the size of a habitat fragment, the more species it can support. Although the total size of both preserves would be the same, each of the divided preserves would support less diversity than a single larger fragment could support.

Endangered species

A species that has a high risk of extinction

Threatened species

A species that is likely to become endangered soon throughout all or part of its range

Which type of species is more likely to become extinct, an endangered species or a threatened species? Explain.

An endangered species; a threatened species is at high risk of becoming endangered while an endangered species is at high risk of becoming extinct.

What is the title of this lesson?

Extinction and Biodiversity Loss -or- Extinction & Biodiversity Loss

Compare and contrast extinction with extirpation.

Extinction occurs when the last member of a species dies. Extirpation, on the other hand, occurs when a particular species disappears from a given area only, not globally.

What human activities lead to habitat loss?

Forest clearing and road building for land use and development

________ change and _______ is the greatest cause of biodiversity loss today.

Habitat fragmentation

List five causes of biodiversity loss.

Habitat change and loss, invasive species, pollution, overharvesting, and climate change.

Habitat Alteration

Habitat destruction or change can limit the number of species a habitat will support. This is the greatest cause of biodiversity loss. Species may become endangered or even extinct if they are trapped, hunted, or otherwise harvested faster that the species can reproduce and grow.

What are "habitat islands," and how do they occur?

Habitat islands are patches of suitable habitat type surrounded by large areas of unsuitable habitat. When humans clear an area for development, they remove, alter, or destroy the resources organisms need to survive.

Poaching

Illegally killing or capturing an organism

What do the photos depict?

Images of a variety of species that are at risk

What information is represented by the Living Planet Index?

Population trends for a group of organisms that are closely tracked.

What are the key concepts for the two main sections of this lesson?

Scientists monitor biodiversity closely and have noticed significantly higher than normal extinction rates in recent decades. Habitat alteration, invasive species, pollution, overharvesting, and climate change are the major causes of biodiversity loss.

How does the background rate of extinction differ from mass extinctions?

The background rate of extinction is the ongoing rate of extinction that always occurs. This is relatively slow but steady extinction. In contrast, mass extinctions occur relatively quickly and involve the extinction of many species at about the same time.

What evidence suggests that we could be experiencing a sixth mass extinction?

The current global extinction rate is much higher than the usual background extinction rate.

Extirpation

The disappearance of a particular population from a given area, but not of the entire species globally

Habitat fragmentation

The process by which the land that is suitable for wildlife becomes separated into smaller patches that are not connected

What do the diagrams show?

The process of habitat fragmentation

How do warming temperatures affect animals that live in cold climates?

Warming temperatures are causing animals to move toward the poles and higher altitudes in search of cooler climate. Some species will be able to adapt. Others, such as polar bears, will not.

Is extinction a natural process? Explain.

Yes. Extinction is a natural process. Organisms have been going extinct for all of Earth's history

List two nonnative species-one that is invasive, and another that is not invasive

Zebra mussels-invasive, nonnative species; honeybees-noninvasive, nonnative species

What are the vocabulary terms for this lesson?

fragmentation loss, extirpation, threatened species, habitat, poaching, endangered species