APES Unit 9 Global Change & Biodiversity Notes

conservation

thinking and using Earth's natural resources in ways that sustain them for future generations.

preservation

thinking and not using Earth's natural resources so that what is present today will also be present in the future.

earths natural resources

-air

-water

-soil

-land

-non-renewables: minerals, mineral salts, oil, coal, natural gas

-biodiversity

protecting biodiversity for intrinsic value

b/c different species exist & have a role in their ecosystem, and share the planet with us, those species have the same right to live on Earth as humans.

protecting biodiversity for instrumental value

b/c of the usefulness of different species - in the form of economic, medicinal, or ecosystem services that they provide us

extinction

-Locally: A species is no longer found in an area it once inhabited but is still found elsewhere in the world.

-Ecologically: Occurs when so few members of a species are left they no longer play its ecological role/niche.

-Globally (Biologically): A species is no longer found on Earth.

background extinctions

the natural evolution and elimination of species from the Earth over a long period of time, humans may not recognize

mass extinction

-extinction of many species in a relatively short amount of time

-each as a result of sudden climate change

5 mass extinctions

-End of the Ordovician

-Late Devonian

-End of the Permian

-Late Triassic

-End of the Cretaceous

characteristics that make a species prone to extinction

-being a K-strategist

-specialized niche

-narrow distribution

-eating at a higher trophic level

-fixed migratory patterns

-rare

-commercially valuable

-large territories

human cause of extinction (HIPPCO)

-Habitat destruction, degradation, fragmentation = loss of habitat

-Invasive species (see invasive species notes for more)

-Population growth of humans

-Pollution

-Climate change

-Overharvest

what speeds up extinction?

-habitat Destruction

-habitat Degradation

-habitat Fragmentation

-habitat Loss

habitat fragmentation

when roads, logging, or agriculture divide larger continuous habitat areas into smaller pieces.

-these disruptions can block migration routes and divide populations into smaller groups, reducing genetic diversity and make the isolated groups more vulnerable to predators, disease, competition.

what makes a species "endangered"?

when numbers of individuals of a species decrease to such a small extent that the species can no longer successfully reproduce, and therefore, may go extinct.

-not all species are in danger of extinction when exposed to changes in an ecosystem.

-some individuals may be able to cope with changes and/or move.

-selective pressures (environmental resistance) & competition can lead to endangerment.

population growth

populations grow rapidly with ample resources, but as resources become limited, growth rate slows and levels off.

-density-dependent (predation; disease) and density-independent (weather events; invasive species; human actions) factors.

indirect consequences of pollution (alligator & shad)

-runoff of fertilizers trigger algal blooms in the Everglades, gizzard shad populations explode.

-at the same time, alligators were dying in unusually large numbers.

-alligators were dying from thiamin (a B vitamin) deficiency

-because the algal blooms helped the population of gizzard shad to explode, the gizzard shad outcompeted other prey of the alligator, alligators ate more gizzard shad, and gizzard shad have the enzyme thiaminase.

What does thiaminase do?

Thiaminase breaks down thiamin = the vitamin B of which the alligators were deficient

The Endangered Species Act of 1973

-protects endangered and threatened species

-forbids federal agencies (besides the defense department) from carrying out / funding projects that would jeopardize an endangered species or its habitat.

-ESA makes it illegal for Americans to engage in business associated with hunting / killing / collecting endangered or threatened species.

The Lacey Act & the Migratory Bird Treaty Act

-Forbid any interstate or international commerce of illegally killed wildlife.

-these Acts were passed to protect birds from people.

-there was a decrease of snowy egrets and other long plumed birds, b/c In the 1800's, fashion dictated the wearing of fancy hats adorned with feathers, so people used to kill the birds to get feathers for the hats.

The U.S. National Wild & Scenic Rivers Act of 1968

established the National Wild and Scenic Rivers System to protect free-flowing rivers with outstanding natural, cultural, and recreational values for the benefit of present and future generations

wilderness act of 1964

-Written to protect undeveloped tracts of land from resource exploitation and development.

-such land became a part of the National Wilderness system and can only be used for wildlife observation, camping, and hiking.

Convention on International Trade in Endangered Species treaty (CITES)

been signed by 169 countries and prohibits the international trade of endangered species and their parts.

why we cant predict extinction

-Extinction takes a long time.

-tt is thought that scientists have identified only a fraction of species.

-scientists really know little about those species present on Earth.

-other unknown or unidentified factors may also play a role.

reconciliation ecology

-involves finding ways to share the places we live, and use, with other species.

-go native (Replace monoculture grasses with native species)...let the weeds grow & hang bird houses

-maintain habitats for insect eating bats and pollinators (bats can control unwanted pests).

-reduce and eliminate the use of chemicals (herbicides & pesticides), which often harm non-target organisms (such as vital insect pollinators).

mitigation strategies

-create protected areas

-construct habitat corridors.

-promote sustainable land use practices.

-restore lost habitat and

-complete land reclamation after mining.