Threats to Biodiversity

Extinction Rates

  • Background extinction: Species slowly die out over time.

  • Mass extinction: Many species die out quickly.

  • Currently, species are dying out 1000 times faster than normal.

Background vs Mass Extinction

  • Background Extinction:

    • Species die off one by one.

    • Happens because of things like climate change or losing their homes.

    • It's a normal part of life as species change.

  • Mass Extinction:

    • Many species die in a short time.

    • Happens because of big, fast changes in the environment or disasters.

Factors Threatening Biodiversity

  • Human actions, like:

    • Habitat loss

    • Pollution

    • Invasive species

    • Using too many resources

    • Climate change

  • Humans are changing things too fast for animals and plants to keep up.

  • Natural resources: Things we get from nature.

Threats to Biodiversity Summarized

  • Humans hurt biodiversity by:

    • Changing where animals and plants live

    • Building on land

    • Cutting down forests

    • Hunting

    • Polluting

    • Bringing in new species

Overexploitation

  • Using too much of things that are worth money.

  • Examples:

    • Passenger pigeons (died out because they were hunted too much)

    • Ocelots (killed for their fur)

    • White rhinoceroses (killed for their horns)

Habitat Loss

  • When animals and plants lose their homes, they have to move or they die.

  • Cutting down rainforests is a big problem for biodiversity.

  • Messing up habitats, like overfishing, can hurt the whole ecosystem.

Habitat Fragmentation

  • When big ecosystems get broken up into small pieces.

  • This makes animals and plants have less variety in their genes and get sick easier.

  • Small areas can't have as many species.

  • Edge effect: The edges of ecosystems are different than the middle.

Pollution

  • Hurts ecosystems and makes biodiversity go down.

  • Biological magnification: Poisons build up in animals that eat other animals.

  • Acid precipitation:

    • Happens when stuff from factories mixes with water.

    • Takes nutrients out of the soil and pollutes water.

  • Eutrophication:

    • Too many nutrients in the water cause algae to grow like crazy.

    • The algae use up all the oxygen, and other things die.

Introduced Species

  • When animals or plants are moved to new places, they don't have anything to stop them from growing.

  • They grow fast and take over.

  • This causes a lot of species to die out.

Climate Change

  • Rising temperatures make it hard for animals and plants to live.

  • Species have gotten used to certain temperatures