Lesson 7.2 Extinction and Biodiversity Loss - Weeblywestsidescience.weebly.com/uploads/4/0/0/8/40082621/biodiversity... · Lesson 7.2 Extinction and Biodiversity Loss Biodiversity

Lesson 7.2 Extinction and Biodiversity Loss

Biodiversity losses caused by humans are

common in our history. Hunting and forest

cutting drove the passenger pigeon—once

North America’s most numerous bird—into

extinction.

Do Now (pg 63): List an endangered

species and a species that is now extinct.

How do you think this happened?

What effects does a species going extinct

or becoming endangered have on a

habitat?

Biodiversity

• Describes the variety of life across all levels of ecological organization• Speciation: process by which new species are generated

• Includes three types:• Genetic diversity: Differences in DNA among individuals

• Species diversity: Variety of species in a given area

• Ecosystem diversity: Variety of habitats, ecosystems, communities

Lesson 7.1 Our Planet of Life

Genetic Diversity Species Diversity Ecosystem Diversity

Lesson 7.2 Extinction and Biodiversity Loss

• Habitat change and loss

• Invasive species

• Pollution

• Overharvesting

Siberian tiger

Causes of Biodiversity Loss

Habitat Change and Loss

• Greatest cause of biodiversity loss

• Organisms, adapted to their habitat, decline in

population when the habitat changes.

• Habitat fragmentation: Patches of suitable

habitat surrounded by unsuitable habitat

• In general, larger habitat fragments can support

greater biodiversity than smaller fragments.

Lesson 7.2 Extinction and Biodiversity Loss

Did You Know? Habitat change or destruction

is the primary cause of population decline in

more than 80% of threatened birds and

mammals.

Invasive Species

Lesson 5.4 Community Stability

• Nonnative organisms that spread widely in a community

• A lack of limiting factors such as predators,

parasites, or competitors enables their

population to grow unchecked.

• Not all invasive species are harmful.

Did You Know? Although the European honeybee is

invasive to North America, it is beneficial because it

pollinates our agricultural crops.

Invasive Species, Pollution, and Overharvesting

Lesson 7.2 Extinction and Biodiversity Loss

• Invasive species can

out-compete and

displace native

species.

• Harmful chemicals

and materials that

make their way into

habitats can poison

people and wildlife.Once common in North America, the passenger

pigeon is now extinct.

Overharvesting•Overharvesting: the endangerment

and extinction of species from overhunting and overfishing

• Extirpation: to destroy completely; kill off

• Poaching: the illegal practice of trespassing on another's property to hunt or steal game without the landowner's permission; poachers often hunt endangered/ threatened species

Biodiversity at Risk

• The current extinction rate is

100 to 1000 times greater than the

natural background rate.

• In 2009, 1321 species in the U.S. were

classified as endangered or threatened.

• Endangered: At serious risk of

extinction

• Threatened: Likely to become

endangered soon through all or part

of its range

Lesson 7.2 Extinction and Biodiversity Loss

Giant panda, an endangered

species

Natural Biodiversity Loss

•Background extinctions:Naturally occurring extinctions, occurring one species at a time

•Mass extinctions: Events when extinction rates far exceed the normal background rate

• There have been five mass extinctions in Earth’s history.

• Each time, more than 1/5 of all families and 1/2 of all species have gone extinct.

Lesson 7.2 Extinction and Biodiversity Loss

Dinosaur extinctions were

part of a mass extinction.

Video- answer questions on back of guided notes

• 7 Pets You Should Never Release into the Wild

Group Workcomplete in pg.63-64 of journal

1. Look at figure 2 on pg 201. Describe what is happening to the tiger population. List 3 reasons why this is occurring. (Answers are in the description below, do not guess)

2. Pg 206 questions 1, 3, 4

3. Pg 211 questions 2, 3

4. Read the section Biodiversity, Tourism and Recreation on page 206. In 4 sentences or more answer: Do you think ecotourism is beneficial or harmful to biodiversity. Use evidence from the text

1.Which of the following is NOT a part of overall biodiversity?A. Species diversityB. Genetic diversityC. Individual diversityD. Ecological diversity

2.Which of the following increases species diversity?A. ExtirpationB. SpeciationC. ExtinctionD. Poaching

3.Globally, the leading cause of biodiversity loss is?A. Invasive speciesB. Poaching and overharvestingC. PollutionD. Habitat change and fragmentation

4.Most scientists think there is a strong connection between biodiversity loss and increasing human population size. How do you think an increased number of people affect biodiversity in your area? Consider each of the major causes of biodiversity loss in your answer.