BiodiversityChapter 10-1, 10-2

Biodiversity Objectives 11Ch. 10-1

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

2. List and describe three levels of biodiversity

3. Explain four ways in which biodiversity is important to ecosystems and humans.

4. Analyze the potential value of a single species

A World Rich in Biodiversity

Biodiversity – def. “Biological diversity” referring to the number of different species in a given area

Why do we want to preserve biodiversity?◦ Our own survival

may depend on maintaining biodiversity

Unknown DiversityCurrently, we are aware of about 1.7 million different

species living on Earth◦ This includes, plants, animals, fungi, bacteria, etc.◦ Most of these species are insects

Scientists believe that more that 10 million species exists on Earth◦ We have not adequately studies all the species on Earth◦ Unknown species may exist deep in forests, in oceans and

even cities

Levels of Diversity1. Species diversity – the number of

different species in an area◦ this is what we think of the most when we

think of biodiversity

2. Ecosystem diversity – the variety of habitats, communities and ecological processes within and between ecosystems

3. Genetic diversity – all the different genes contain within member of a population

◦ A gene is a small piece of DNA that codes for a trait

Importance of Biodiversity #1: Species are Connected to EcosystemsKeystone species – is a species that is so

critical to the healthy functioning of an ecosystem, that removing it would cause the whole ecosystem to collapse◦Ex: sea otters control the kelp beds by eating

urchinsWe may not always know how important a

species is until they are all gone

Keystone Species – The Concept

Importance of Biodiversity #2: Species and Population SurvivalGenetic diversity refers to having

wide variety of traits in a population

This increases the chance that some members will survive if an environmental crisis occurs

The population may re-grow after an environmental crisis, but with limited genetic diversity, more member are likely to inherit genetic diseases

Importance of Biodiversity #3: Medical, Industrial, Agricultural Uses

Almost all of our antibiotics come from chemicals produced by fungi

About ¼ of pharmaceutical drugs are derived from plants

New chemicals and materials may be created by all kinds of species!◦We can now make plastic from

plants!What are some other uses you

can think of?

Importance of Biodiversity #4: Ethics, Aesthetics, RecreationSo why else should we fight to keep

biodiversity high? Many believe that all species have a right

to exists regardless of their “importance” to us

Other believe that all species should exists for religious reasons

Other still, believe we should preserve biodiversity simply to enjoy it in nature◦Ecotourism is a form of tourism that supports

the conservation and development of ecologically unique areas

Biodiversity At Risk - Objectives Ch. 10-2

1. Define and give examples of endangered and threatened species

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

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

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

5. Compare the amount of biodiversity in the US to that of the rest of the world

Current ExtinctionsWe are in the middle of a mass extinctionThis one is different that past mass extinctions

◦ Humans are the Cause!!Endangered species – is a species that is likely to

go extinct if protective measures are not taken immediately

Threatened species – will become endangered soon if protective measures are taken. Declining numbers.

How do humans cause extinctions?

1. Habitat destruction and fragmentation◦ By building homes, using land for agriculture and

urban development, we are stealing habitat from animals

2. Invasive Exotic Species◦ We are carrying species from one place to

another that do not belong. The new species then outcompete the native species

3. Harvesting, Hunting and Poaching◦ Ex: the dodo bird

4. Pollution

Areas of Critical BiodiversityEndemic species – a species native to

and limited to one area but may be beneficial for a much greater area

Areas of high biodiversity:1. Tropical Rain Forest – cover less than 7%

of the globe BUT contain more than 50% of the worlds species

2. Coral Reefs and coastal Ecosystems – the marine version of tropical rain forests

3. Islands – once formed, islands are colonized by a small group of species from the main land that evolve into new distinct species

Biodiversity HotspotsBiodiversity hotspot – a high-diversity area that

is directly threatenedMany species have already been lost in these

areas due to human activityMost of these are Tropical rain forests, coastal

areas and islandsA few Hotspots are right here in the US!

◦ We have so many different types of ecosystems with unusual characteristics, we must take care to preserve every one

◦ Threats to our hotspots come from : Agriculture, housing, dam construction, overuse of water,

destructive recreation and mining…all because of population growth!

US Biodiversity Hotspots