bio exam 2 ( help from quizlet)

genetic engineering

can be defined as a transfer of genes for desirable traits, such as a pest resistance, into crop plants from other organisms

tropical rainforest; tropical seasonal forest

In contrast with the _____, the soil of the ____ s more nutrient rich in this type of biome has fewer insect parasites and fungal diseases. Therefore, in many places, these areas are highly endangered.

What is the advantage of genetically modified crops (GMOs)?

all of the above

Highly persistent toxic chemicals

retain their toxicity as they cycle through the food chain and environment

The IUCN world conservation strategy is directed at protecting

ecosystems and biodiversity.

Methods of managing topography include all but which of the following?

deep tilling

In developed countries, the most recent increases in agricultural productivity have come from

new crop varieties and intensified farming.

Undernourished parents often raise children who are undernourished because the parents

cannot afford to feed their children properly.

The giant panda is considered to be a _________________ species.

flagship

One biome type that has not been as badly threatened as other biomes is

arctic tundra

The World Health Organization regards health as primarily a matter of ________ well being.

physical, mental, and social

Which of the following statements about trade in endangered species is false?

Overharvesting affects animals more than plants.

An LD50 (lethal dose 50%) is a dose of a toxic chemical that

kills half of the population.

Which nation listed below has the highest deforestation rate?

brazil

Historically, the greatest threat to grasslands has been

conversion to farmland.

Over the past decade, the number of park visitors has _______ and park budgets have ________.

increased by one third; decreased by about 25%

The primary difference between a bog and a fen is

fens are fed by groundwater, bogs are fed by rainfall.

Wind erosion is most likely to cause problems in

open, arid regions

Soil organisms usually stay __________ the soil.

close to the surface

Hazardous substances ______________ while toxins are ______________.

are dangerous substances; poisonous substances

The temperature boundary in freshwater lakes is the

thermocline.

The total number of living species is probably

Between 3 million and 50 million

The location of specific biomes can be predicted based on

precipitation and temperature.

Which of these is not a benefit found with reduced tillage farming?

decreased insects and weeds

Waterlogging results from

excessive irrigation

A natural form of fertilizer would be

manure

High responder crops of the green revolution produce tremendous yields

in response to fertilizers, pesticides, and irrigation.

The EPA usually assumes an acceptable risk for environmental hazards is about 1 in

one million

The USDA estimates ______ percent of conventionally grown foods are contaminated with pesticide residue.

73

The energy needed to process and distribute food in the US is as much as _______ times the amount that is used to actually farm the crops.
Group of answer choices

5

Famines are most often serious when there is

drought and war together

With respect to exposure to toxins which statement is correct?

Acute effects are the immediate results of a single exposure, chronic effects are those that are long-lasting.

Approximately how many species have been identified on Earth?

about 1.5 million

Which of the following would not be among the most important characteristics of chemicals in determining their environmental risks is/are

dose

The most sustainable land use in tropical forests is probably
Group of answer choices

milpa farmimg

Goiter is a common disease resulting from a shortage of dietary

iodine