grade 8 biodiversity

Levels of Biodiversity

Genetic diversity - different genes & combinations of

genes within populations

Species

Organisms that have the potential to interbreed in nature

and produce viable, fertile offspring

Population

A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring.

Species diversity - number of different species represented in a

given community

Ecosystem diversity -

variation in the

ecosystems found in a

region

Which is more diverse?

A B

Which is more diverse?

A B

Which is more diverse?

A B

A B

Which is more diverse?

Which has more biodiversity?

A B

There is an estimated 8.74 million

species on the planet.

86% of all land species and 91% of all

marine species have NOT been

discovered yet.

Genetic diversity: source of variations that enablepopulations to adapt to environmental changes

Species diversity: important in maintaining structureof communities and food webs

Ecosystem diversity: provides life-sustaining servicessuch as nutrient cycling and waste decomposition

Threats to biodiversity•H•I•P•P•O

http://en.wikipedia.org/wiki/File:Lacanja_burn.JPG

Habitat Loss

Habitat loss is the greatest reason for

biodiversity loss.

Mid 1960’s Mid 1970’s Mid 1980’s

Primary Forest Secondary Forest

Invasive / Exotic Species

Introduced usually by human activities.

They are generally thought to cause

economic or environmental harm.

Are all invasive/introduced species harmful?

•Most introduced species are beneficial to society.

• Introduced species provide food, shelter, medicine, and aesthetic pleasure.

•Some organisms are introduced to control the populations of invasive species.

Pollution

Pollution (Oil spills, human agricultural waste,

fertilization, pesticides, acid deposition,

greenhouse gases, etc) caused by human activities

has a negative effect on biodiversity.

Population (Overpopulation)

•7.3 Billion and counting.

•The expansion of human population and affluence, especially in the developing world harms natural ecosystems.

Overharvesting, Overuse, Overexploitation

•Overhunting, overfishing, destructive harvesting practices (cyanide, dynamite), illegal trade, exotic pet industry

Destructive Fishing Practices

Seventy percent of each haul of

trawler fishing is considered by-

catch.

Dolphin as by-catch in drift net.