1

BiodiversityChapter 10

Modified from P. Green (WHS)

2

Section 1 What is Biodiversity

3A World Rich in Biodiversity

Biodiversity – the number of different species in a given areaTropical rain forests have highest biodiversity on earth

Known species – species that are collected and described scientifically1.7 million species (most of which are insects)

Unknown species – Species not identified as of yet, located in remote locationsMore than 2 million possible (to be identified)

Levels of diversitySpecies diversity : Number of species in a given area (most commonly know as

biodiversity)Ecosystem diversity: All the different habitats and ecological processes in an

ecosystemGenetic diversity: All the different genes in all the members of a population

A gene is a part of DNA that determines one particular trait (blue eyes, widow peak)

4Benefits of Biodiversity

• Species are connected to ecosystems.• Every species is either dependent on or depended upon by at least one other

species. • Think food webs, niches (niche = a species’ role in an ecosystem)• Keystone species – critical to the entire ecosystem• Sea Otters: loss of the otter - led to the loss of kelp beds

5

Benefits of Biodiversity

Species and Population Survival• Genetic diversity is critical to species survival.• Environmental changes affect less diverse populations more• Ice Age – species not adapted to cold die - but species with genes to survive

cold live on• If no one in species had cold gene, all die• But what happens to genes in all the species that died?

• All other genes lost

Bottleneck effect – When a population is reduced to a few members. Only certain genes get through the event.

6

• Medicines and cures are constantly being found as we locate new species

• Industry finds new chemicals in all types of species• Better resistant crops being made because of genetic crossing• Ethics, Aesthetics, and Ecotourism• Should we preserve species because they deserve to be here?• Should we preserve species because they are nice to look at and make

our lives beautiful

• Ecotourism – a form of tourism that supports the conversation and sustainable development of ecologically unique areas.

7

That’s all for 10.1

• Time for a reading quiz

Section 2 Biodiversity at Risk 8

9

Current Extinctions

• Mass extinction – extinction of many species in a short period of time• Five previous mass extinction events • Due to global climate change• Dinosaurs: ice ages and meteorites

• Possible cause of the next (current??)mass extinction:• Due to human activities• From 1800 to 2100 up to 25% of all species may become extinct

• Endangered species – species that will go extinct if not protected immediately• Usually a small population in a limited habitat

• Threatened species – species will become endangered if not protected

10How Do Humans Cause Extinctions

• Habitat Destruction and Fragmentation• We use land for homes and food

production• In the process – we destroy and fragment

the habitats of other species.• Habitat loss is causing 75% of all current

extinctions• Florida Panther: one of the most

endangered species in North America (due to habitat loss)

11

How Do Humans Cause Extinctions

Invasive species• New species introduced to an environment• Native species have no defenses, and new species have no predators• Kudzu, Cane Toads, Fire Ants

• Harvesting, Hunting, Poaching• Passenger pigeon hunted out of existence, bison close• People want rare species as a pet, food, medicine• Monkey brains, shark fins,

• Poaching – capturing protected species against the law• Ex: elephants for ivory (tusk) ; tigers for healing properties

Pollution• Chemicals being dumped have harmful effects on other species

Ex: DDT in the food chain caused bald eagle egg shells to weaken• Bald eagle nearly extinct until DDT banned.

12

Areas of Critical Biodiversity

• Endemic Species – species that live in a small specific habitat• Tropical Rain Forest• Home to half of world’s species• Most not yet observed, but losing them as we clear the rain forest for

farming and housing

• Coral Reefs – Most of biodiversity in ocean• A major source of food and ecotourism• In danger due to overfishing, and pollution

• Hot Spots – the most threatened areas of high diversity on Earth• Madagascar, Philippines, Florida Everglades, California Coast, Hawaii

• United States Biodiversity• We have several of the hotspots (Florida Everglades / coastal regions)• Are we taking care of them?

13

That’s all for 10.2

• Time for a reading quiz

Section 3 The Future of Biodiversity

14

Saving Species One at a Time

• When a species is nearing extinction what can be done to help?• Captive breeding• Species are bred in captivity (zoos or shelters) and will be released

into wild when enough are bred• California Condor

• Preserving Genetic Material• Germ plasm – genetic material from reproductive cells• Stored (usually frozen) for future use.• Same as heirloom tomato seeds!

• Zoos and Aquariums• Not just for entertainment• Home for endangered species• Successful breeding programs - Pandas!

15

Preserving Habitats and Ecosystems

• Conservation Strategies• Focus on whole ecosystem not individual species• Restore native habitats and expand them

• Legal Protections - US• Endangered Species Act – passed in 1973• Fish and Wildlife Service must keep list of all endangered or threatened

species• Endangered and threatened species cannot be caught or killed.

Endangered/threatened plants may not be uprooted

No part of an endangered/threatened species may be sold or traded• US Government cannot do any projects that might impact listed species• The U.S. Fish and Wildlife Service must prepare a species recovery plan

16

Legal Protection – International• IUCN – International Union for the Conservation of Nature and

Natural ResourcesAdvise governments on endangered speciesPublishes a “Red Lists” of endangered species around the world

• CITES – Convention on International Trade in Endangered Species• Elephant Ivory Tusks – Poachers after them• CITES made a worldwide ban on selling ivory• Elephant poaching dropped

• Biodiversity Treaty• Agreement generated during the Earth Summit (1992 – Rio de Janeiro)• Goal is to preserve biodiversity and ensure sustainable/fair use of

genetic resources in ALL countries

17

18

That’s all for 10.3

• Time for a reading quiz