Ch. 10 - Biodiversity

Sect. 1 Objectives

• 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 and humans.

• Analyze the potential value of a single species.

Biodiversity(biological diversity) – the number of different species in a given area

• Plants – Trees, shrubs, flowers, weeds

• Animals– Mammals, insects, fish, crustaceans

• Fungus

• Insects

• Bacteria

• Etc.

How many are there?

• 1.7 million species are known– Most are insects

• 10 million species are estimated to exist

Levels of Diversity• Species diversity – number of different

species in an area

• Ecosystem diversity – variety of habitats, communities

• Genetic diversity – number of genes contained in all members of a population

What makes everything different?

• Genes (DNA) – code for different traits or characteristics that can be inherited– Everyone's is different (unless you are an

identical twin)

Why is Biodiversity Important?

• All species are dependant on other species and are depended on by others

• Everyone fits in the food web/chain

• If you remove

one link, all the

others will fall

Keystone species – a species that is critical to the functioning of the ecosystem

because it affects the survival and abundance of many other species

• – one species that many others depend on

Ex: Sea Otters

• 1. Otters killed for fur• 2. Sea urchin population grew• 3. Kelp disapeared

Ex: Prairie dogs

Biodiversity and Survival

• More genetic diversity means the population has a greater chance of surviving environmental changes. (ie: global warming)

• Ex: Hemophilia

Biodiversity and Humans

• More organisms the more things for us– Food– Antibiotics– Clothing– Shelter– Chemicals

Ecotourism – tourism that supports the conservation and sustainable development of

ecologically unique areas

• Has become very popular lately

Sect. 2 Objectives

• 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.

All species are considered one of these: depending on their natural

numbers

• Extant

• Threatened

• Endangered

• Extinct

Extant – living animals

Threatened – still abundant in its natural habitat but is likely to become endangered because

of their declining numbers

       

                              

Endangered – so few individuals that they are likely to become

extinct

Extinct – no known individuals still alive

Species most at risk

• Animals that are more likely to become extinct are those that:– Have small populations– Migrate– Need large or special habitats– Are exploited by humans

• Currently humans are the greatest cause of extinctions!

Species can be threatened by

• Humans – Hunting– Loss of habitat (75% of

current extinctions)

• Deforestation• Damming• Burning• Growing cities• Pollution

– Poaching – Invasive species

• Natural Causes– Interbreeding– Natural Disaster– Disease

Exotic – not native to an area

• When brought to a new area exotic species can cause the extinction of other species they out compete

• Ex: Fire Ant– Horny Toads (Desert Horned Lizard) eat ants– Fire ants (exotic species) kill horny toads. – Horny toads are now threatened!

Generalist Species

• Species with a broad niche, can survive in many different places

HUMANS

Often are invasive species

Specialist Species

Species with a narrow niche. Only live in a small range of environmental factors

Fewer if these because they can become extinct more readily

Critical Areas

• Tropical Rain Forests – over half the worlds species live here– Most species have not been named, yet– But, lots of these are disappearing

• Due to habitat destruction by humans!

• Coral Reefs and Coastal areas

• Islands – why?

Biodiversity Hotspots – high number of endemic species but are threatened by humans

Madagascar

• Biodiversity Hotspot– Endemic Species

• 80% of plants • 91% of reptiles• 100% of lemurs (10% of worlds primate

population)

• Only 18% of the original forests remain!!

Sect. 3 Objectives

• List and describe four types of efforts to save individual species.

• Explain the advantages of protecting entire ecosystems rather than individual species.

• Describe the main provisions of the Endangered Species Act.

• Discuss ways in which efforts to protect endangered species can lead to controversy.

• Describe three examples of worldwide cooperative efforts to prevent extinctions.

Ch. 10 Ecolog• Read in your book, in Sect. 3, about the

following ways to save species. In your Ecolog write a brief description of each!– Captive-Breeding programs– Preserving Genetic Material– Zoos, etc.– Conservation Strategies

• Write a paragraph about why it is important to save species and the biodiversity around the world.