envi sci 3X multiple choice

What is desertification

the loss of more than 10% of soil productivity in arid areas due to such factors as erosion, soil compaction, overgrazing, and forest removal

What is the greatest cause of the worldwide loss of species

habitat destruction

Removal of which of the following species will result in the greatest changes of an ecological system

a keystone species

where is the greatest species diversity found

insects

animals that are harmed by human modification of the environment have which characteristics

being large

a habitat specialist

having a small geographic range

a dietary generalist

being high on the food chain

what is the O horizon

composed of organic materials

beneficial roles insects serve in agriculture

essential pollinators and predators

which of the following activities would violate CITES

your friend brings back an ivory chess set that he bought in Lesotho

what is CITES

Convention on international trade in endangerd species of wild flora and fauna

What did normal borlaug pioneer

high-yield wheat: disesase resistant wheat

Primary Goal of the green revolution

introduce new tech and farming practices

What is integrated pest maagment

combines synthetic chemical pesticides with biocontrol techniques

results of overlapping fertilizer

eutrophication in nearby waterways

why does irrigation result in thesalinizatino of soils

salts in the water are depositied on the soil surface as water evaporates

industrial agriculture

has increased our ability to obtain more food from the same area

during the past half century, global food productino has grown

at a faster rate than population growth

where is the greatest diversity found in

invertebraes - no backbone

why does bioiversity enhance food security

new potential sources of foods or variety of current foods

what do paleon toligists estimate

99% of all species that have ever existed are now extinct

describe the effects changes in habitat have on the organims that depend on them

generally negative; organisms are already adapted to the habitats in which they occur and any change is likely to render the habitat less suitable

what led to the recovery of bald eagle numbers in the 1970s

the ESA was passed and DDT was banned in the US - DDT thinned eaagle egg shells

contrary to popular belief ESA allows

ppl to harm an endangered species if they restore that same species’ elsewhere

second growth forests

become established after virgin timber has been removed from an area

prescribed burns would be used in forests when

trying to restart growth

forests are subject to severe wild fires to removed fuel load

what system uses timber harvesting involving leaving small numbers of mature trees in place to provide shelter for seedlings as they grow

shelterwood

What accurately describes the benefit or a drawback of managing an eve-aged tree plantation

evan aged stands that are more vulnerable to pests such as bark beetles

How much of Earth’s land area is covered by forest

30%

what is the precautionary principle

restrict any chemical that is suspected of toxicity until is is demonstrated to be safe

synergistic effects of toxicants

are greater than the sum of th effects of the components

The concentration of DDT in a certain lake is 0.0000003 ppm (parts per million), while the concentration of DDT in the tissues of a nearby osprey (a fish-eating bird) is 25 ppm.
What is this an exmple of?

biomagnification

why are aquatic animals such as fish and frogs good indicators of water pollution

most chemicals are water soluble so they enter these organisms thru drinking or skin absoption

Chronic exposure levels vs. acute exposure

safe levels for chronic exposure to a toxicant are lower than safe levels for acute exposure

acute exposure to an environmental toxin issss

a high exposure over short times and associated with a specific cause

what are pathway inhibitors

they are toxicants that interrupt essential biochemical processes in organisms by blocking one or more steps in important biochemical reactions

Carcinogens

can cause cancer

difficult to identify bc there is a long log time btwn exposure to the agent and disease