IB Bio More Second Year Ecology

biological control

using natural predator or virus to control invasive species

bad example of biological control

Indian mongoose introduced to Hawaii to eat rats that arrived on boats but don't eat rats --> ate native bird eggs --> extinction; metal rings around trees to prevent climbing

good example of biological control

BT (bacillus thuringiensis) - bacteria that kills larva of pests (caterpillar, hematoads); safe for predatory insects

biological magnification

process by which chem substances become more concentrated at each trophic level

DDT (Dichlorodiphenyltrichloroethane)

insecticide, makes bird eggs more brittle/crack easily (ex: eggs of seabirds)

most things that are biomagnified are stored in _______, since ________ tend to be last resort for energy & aren't broken down

fat tissue, lipids

tuna & swordfish have a high concentration of ________

mercury

ozone (O3) layer

in stratosphere; absorbs UV radiation

what occured in 1985?

data collected on ozone layer showed dramatic depletion

thinning of ozone layer was caused by the release of _____

CFCs (chlorofluoro carbons)

CFC in the presence of UV light becomes _____

Cl-

Cl- in the ozone layer becomes

chloroxide

equation for circular process that led to thinning of ozone layer

Cl- + O3 = ClO + O2
ClO + ClO = 2Cl- + O2

conservation biology

attempt by scientists & governing bodies to maintain or increase biodiversity

how can humans increase biodiversity? (5)

physically remove invasive species, clean up polluted environment, spread edu. on biodiversity, create protected areas (ex: national parks), lessen carbon footprint

indicator species

species whose presence tells us something about biodiversity or health of environment

_____ are good indicator species, can only be supported by a health ecosystem

large carnivores

_____ are good indicator species, sensitive to chemicals/pollutants

amphibians

in management of conservation areas, ______ requires both prioritization & funding (3)

restoration, threatened/endangered species, removal of introduced species,

three factors needed for reserve to be successful

1. size
2. edge effect
3. corridors

why is size of nature preserve important?

larger size, less edge effect

edge effect

how much influence humans or other invasive species have on nature preserve

corridors

strip of natural habitat that connects separated populations; still maintains infrastructure

cowbirds

brood parasitoids that lay eggs in other birds' nests, hatchlings dominate the nest

extinction

death of every member of a species; local or global

examples of extinct species

dodo bird, Carolina parakeet, Tasmanian tiger/wolf

how do humans contribute to extinction?

humans accelerate extinction rates

causes of extinction (6)

change, in general, causes extinction; habitat loss, disease/epidemic, climate change, invasive species, overhunting, lack of resources

keystone species

species that influences survival of many other species in ecosystem; essential species in ecosystem

removal of a keystone species from a community will...

have a disproportionate effect; may collapse ecosystem (ex: honeybees, sea otters)