Biology Today Third Edition Chapter 18 Biodiversity and Threatened Habitats Copyright © 2004 by Garland Science Eli Minkoff Pam Baker

Chapter 18 Biodiversity A. Definitions biodiversity, communities, niche B. Diversity Value of biodiversity ? Ways to preserve Loss of diversity Extinction (true- or pseudo-) C. Ecosystems (Biomes) Changes in communities Succession – primary and secondary Climax Community is mature, natural ecosystem stable population sunlight supplies energy chemical are cycled energy flows through system (lost as heat) Destruction of ecosystems examples:deforestation, desertification

Chapter 18 Biodiversity A.Definitions biodiversity, communities B.Diversity Value of biodiversity ? Ways to preserve Loss of diversityExtinction (true- or pseudo-)

Chapter 18 Biodiversity C.Ecosystems (Biomes) Changes in communities Sucession – primary and secondary Climax Community is mature, natural ecosystem  stable population  sunlight supplies energy  chemical are cycled  energy flows through system (lost as heat) Destruction of ecosystems examples: deforestation desertification

Biodiversity and Habitat Number and variety of species present Place to live

Biodiversity The more we look, the more we find. 1.5 million species identified 5-30 million estimated species

Figure 18.1

Communities interdependent species living in the same place Niche unique role in community Ecosystem community interacting with it’s environment

Biodiversity A measure of the complexity of the ecosystem A major influence on biodiversity is Lattitude (how close to the equator) i.e., how much sunlight (energy) Tropics -reef and rain forests

Figure 18.2 Red Sea, Egypt

What is the value of preserving diversity ? Might be losing something valuable Genetic variation

Corny illustration pg. 646 Domestic cornvaluable, annual Zea mays Wild corn Zea diploperennis disease resistant perenial Genetic diversity (a good thing)

Ways to preserve genetic diversity zoos botanical reserves gene banks (cryopreservation) … The cheapest way is to promote diversity in their natural habitats chimps

“The health of animals, is promoted by the variety of plants available for them to eat or to climb or to nest in. Likewise, the health and well-being of many of the plants depends on the variety of animals that can pollinate them, disperse their seeds, or fertilize the ground near the roots…” BT3 pg 647

Decline in Biodiversity Extinction -disappearance of a species true entire lineage dies out

Figure 18.3 (1)

Figure 18.3 (2)

Figure 18.3 (3)

Decline in Biodiversity Extinction -disappearance of a species true entire lineage dies out pseudo- similar ancestors survive

Hyracotherium

Figure 18.4

Figure 18.6

Figure 18.5 (1)

Figure 18.5 (2)

Figure 18.5 (3)

extinction ?

Figure 18.6

Reasons for extinction Climate? Asteroid? Volcano? Glacier? Humans

Moa birdNew Zealand Elephant birdMadagascar Dodo bird Passenger pigeon Bachman’s warblerUS MollusksOhio FishesLake Victoria … Extinct animals (a few from pp ) 100,000 during from

Endangered species lots

Threatened habitats

Biomes A group of similar ecosystems climate species habitat similar

Figure 18.9

Figure 18.10a

Figure 18.10b

Figure 18.10c

Biodiversity in the Tropical rain forest

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Mutualism

Figure bulls horn acacia ants

Ant feed on plant nectar Ants attack animals that try to harm the plant

Figure Complex mutualism pp. 664 ff. three fruit types three generations of wasps seed dispersal FIGWASP

Figure 18.15

Community Change Succession - the sequential change, over time, of the populations within a community –Primary (centuries) Volcanic island Glacier retreat –Secondary (decades) Abandoned field After a forest fire

Community Change Succession - the sequential change, over time, of the populations within a community If no change is occurring, the community is a stable, climax community or a mature, natural ecosystem.

a a

Mature Natural Ecosystem 1.Stable population (climax community). 2.Sunlight supplies the energy. 3.Chemical are cycled (short term). 4.Energy flows through the system.

Climax Community stable (doesn’t change) takes a long time to establish takes a long time to recover deforestation & desertification

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We take too much from the environment We are poisoning ourselves (air, water, land) We use (and waste) too much energy It can’t go on like this forever Sustainability

Chapter 18 Biodiversity A. Definitions biodiversity, communities, niche B. Diversity Value of biodiversity ? Ways to preserve Loss of diversity Extinction (true- or pseudo-) C. Ecosystems (Biomes) Changes in communities Succession – primary and secondary Climax Community is mature, natural ecosystem stable population sunlight supplies energy chemical are cycled energy flows through system (lost as heat) Destruction of ecosystems examples:deforestation, desertification