Describe the diversity of species types on Earth, relating the difference between known numbers and estimated numbers.

List and describe three levels of biodiversity.

Explain four ways in which biodiversity is important to ecosystems.

Analyze the potential value of a single species.

Why are some species better suited for certain habitats than others? Why might a species become less well suited for its habitat over time? What must the species do if it is no longer well suited for its habitat? - Write in complete sentences. At least 5 lines.

Biodiversity – short for “biological diversity,” refers to the number of different species in an area

Certain areas of the planet have an extraordinary variety of species; i.e. the tropical rainforest

Relationships between species are complex so it is important that we preserve biodiversity for our own survival

To understand biodiversity we must identify all of the species that exist on Earth. This is a never ending task!

The known number of species is 1.7 million, mostly insects.

Most scientists estimate there are about 10 million species. Many unidentified species may be in the ocean or in remote wilderness.

Levels of Diversity: Species Diversity – number of different

species in an area; also known as biodiversity

Ecosystem Diversity – variety of habitats, communities, and ecological processes

Genetic Diversity – all of the different genes contained by the members of a population▪ Gene – a piece of DNA that codes for a

specific trait that can be inherited by an organism’s offspring

Species Are Connected to Ecosystems

A healthy ecosystem has balanced cycles of energy and nutrients. Species are part of these cycles.

Species have important roles in their ecosystems and either depend on or are depended upon by one or more other species. When one species disappears it might have serious implications for the ecosystem.

Check Your Understanding: We have learned about several cycles (food webs, carbon cycle, nitrogen cycle). Give a few examples of how organisms are part of these cycles.

Keystone Species – a species that is clearly critical to the functioning of an ecosystem. The ecosystem changes or collapses with out this species.

Example of Keystone Species: Sea Otter – sea otter prey on sea urchin.

Without sea otter the urchin population grows out of control and destroys the kelp bed ecosystem

Genetic diversity is critical to species survival. It increases a species chance for survival environmental changes.

Small, isolated populations are less likely to survive changes.

We use other organisms for food, clothing, shelter, and medicine.

Check Your Understanding: Give some examples of other species we use.

About 25% of the drugs prescribed in the United States come from plants. There may be other medicine that can come from plants we have not yet discovered.

Reasons Why We Should Preserve Biodiversity: Ethics – Species have the right to exist

Aesthetics – Organisms and wildlife are beautiful so they should be preserved

Recreation – We should preserve species so we have places to camp and hike. Ecotourism is tourism that happens in ecologically unique areas.

Define and give examples of endangered and threatened species.

Describe several ways that species are being threatened with extinction globally.

Explain which types of threats are having the largest impact on biodiversity.

List areas of the world that have high levels of biodiversity and many threats to species.

Compare the amount of biodiversity in the United States to that of the rest of the world.

It is estimated that between 1800 and 2100, up to 25% of all species on Earth may have become extinct.

Species Prone to Extinction Endangered Species – a species that is likely to

become extinct if protective measures are not taken immediately

Threatened Species – a species that has declining populations and is likely to become endangered

Habitat Destruction and Fragmentation As our population grows we build more homes and

use more resources. This results in the destruction of habitats or fragmentation. Fragmentation is when we break a habitat up into smaller parts. This is a problem for organism that require a large territory.

Invasive Exotic Species Exotic species are species that are not native to a

particular region. These are many times brought to the new area by humans. These species may become invasive, meaning they take over, because they have no predators to control their populations.

Harvesting, Hunting, and Poaching Excessive hunting and harvesting of

species can also lead to extinction. Many countries now have laws to regulate hunting, fishing, and harvesting. However, poaching, which is illegal hunting of a species, still happens frequently.

Pollution Pesticides, cleaning agents, drugs, and

other chemicals used by humans can affect the food web.

Endemic Species – species that are native to and found only within a limited area

Tropical Rain Forest Remaining tropical rain forest is less

than 7% of the Earth’s surface. However, scientists estimate that over half of the world’s species live there!

Coral Reefs and Coastal Ecosystems Coral reefs occupy only a small fraction of the

marine environment yet contain a majority of the biodiversity there. They also provide food and tourism revenue. Nearly 60% of the Earth’s coral reefs are threatened by human activities like overfishing and pollution.

Islands Islands contain species that have specially

evolved to live on those islands. These species may not be found anywhere else in the world.

The most threatened areas of high species diversity have been labeled biodiversity hotspots.

Most of these hot spots have lost at least 70% of their original vegetation.

Hotspots are mostly tropical rain forests, coastal areas, and islands.

Biodiversity hotspots in the United States include the Florida Everglades, the California coastal region, Hawaii, the Midwestern prairies, and forests of the Pacific Northwest.