Unit 2: The Living World

LT 6

100

The ultimate source for terrestrial ecosystems is a) nutrients in the soil b) nutrients in vegetation c) primary consumers d) producers e) the sun

e) the sun

200

Which of the following is the best example of a keystone species? a) beaver b) sea urchin c) spotted owl d) snail e) coyote

e) coyote

300

Why do introduced species often become pests? a) they displace native species b) they increase biodiversity c) they do not adapt well to local habitats d) they contribute to habitat fragmentation e) they have low biotic potential

a) they displace native species

400

What is carrying capacity? a) the maximum amount of organisms in an ecosystem b) the maximum amount of food an organism can intake c) the maximum amount of organisms an ecosystem can maintain d) the total number of organisms in an ecosystem e) the rate of population growth in an ecosystem

c) the maximum amount of organisms an ecosystem can maintain

500

A symbiotic relationship between two living organisms in which one organism benefits and the other is neither harmed nor helped is known as a) commensalism b) predation c) parasitism d) mutualism e) competition

a) commensalism

LT 7

100

Of the following organisms, which occupies the lowest trophic level? a) spider b) deer c) lion d) hawk e) snake

b) deer

200

Photosynthesis is the major source of which of the following gases in the Earth's atmosphere? a) CO2 b) H2O c) O2 d) H2 e) N2

c) O2

300

All of the following statements about the biomass pyramid is true EXCEPT a) biomass is the total dry mass of the organisms present b) the base of the pyramid generally represents primary consumers c) the amount of biomass at a particular level of the pyramid depends on the amount of energy available d) the width of the base of the pyramid varies with different ecosystems e) the amount of energy decreases as you move up the pyramid

b) the base of the pyramid generally represents primary consumers

400

What is a measure of the amount of biomass remaining after respiratory loss in plants? a) ecological succession b) net primary productivity c) gross primary productivity d) law of tolerance e) energy pyramid

b) net primary productivity

500

Which of the following is an example of the second law of thermodynamics? a) ecological succession b) symbiotic relationships c) carrying capacity d) photosynthesis e) the 10% rule

e) the 10% rule

LT 8

100

Characteristics that tend to increase the risk of a species becoming endangered include which of the following? I. having a very limited distribution II. being a specialist species at the end of a long food chain III. having a small population size a) I only b) II only c) III only d) II and III only e) I, II, and III

e) I, II, and III

200

Which of the following best shows the process of evolution? a) a lizard's color becomes brown as it sits on a log b) a bear goes into hibernation c) a plant loses its leaves in a drought d) a population of mosquitoes develops resistance to a pesticide e) a population of foxes increases as more prey becomes available

d) a population of mosquitoes develops resistance to a pesticide

300

A one-hectare pond is sampled in early September. The sample yields 1 small catfish and 17 benthic invertebrates that represent 10 species. Which of the following can be estimated from the sample for the invertebrates in the pond? a) the species richness b) the pond's productivity c) the species evenness or the uniformity of species distribution d) the degree of disturbance e) the stability of the ecosystem

a) the species richness

400

Which of the following statement about genetic diversity is true? a) genetic uniformity of a crop increases the crop's overall resistance to pests and disease b) genetic resistance to pests and diseases can be increased by crossing a crop plant with ancestral varieties c) genetic engineering technology is used to increase genetic diversity by creating a new species with synthetic genes d) genetic diversity within populations of common crop species such as corn is typically high e) genetic diversity is usually high in endangered species

b) genetic resistance to pests and diseases can be increased by crossing a crop plant with ancestral varieties

500

Humans negatively affect biodiversity in all of the following ways EXCEPT a) deforestation b) urban development c) habitat preservation d) drilling for oil e) hunting and poaching endangered species

c) habitat preservation

LT 9

100

If global temperatures keep on increasing as predicted by scientists, which of the following is most likely? a) there will be fewer insect pests and disease-carrying organisms b) specialist species living in fragile ecosystems will risk extinctions c) there will be an increase in sulfate concentrations in wetlands d) there will be an increase in the reproductive rate of mammals e) the geographic range of many plants will move toward the equator

b) specialist species living in fragile ecosystems will risk extinctions

200

This biome typically has acidic soil due to waxy pine needles a) tundra b) taiga c) desert d) grassland e) savanna

b) taiga

300

Which of the following countries has the largest amount of boreal forests? a) Australia b) Brazil c) Chile d) Russia e) United States of America

d) Russia

400

Which of the following best describes the mechanism of the greenhouse effect in Earth’s atmosphere? A) Ultraviolet radiation from the Sun is absorbed by ozone gas in the stratosphere B) Gamma radiation from the Sun is absorbed at ground level by dust particles in the atmosphere C) Infrared radiation from the Earth’s surface is absorbed by gases in the atmosphere D) Cosmic radiation from deep space is absorbed by gases in the atmosphere E) Alpha radiation from the Sun is absorbed by water vapor in the atmosphere

C) Infrared radiation from the Earth’s surface is absorbed by gases in the atmosphere

500

Which of the following would most likely occurs after a disruption from a volcanic eruption? a) symbiosis b) primary succession c) secondary succession d) tertiary succession e) law of resilience

b) primary succession

LT 10

100

During the carbon cycle, which of the following carbon compounds is released into the atmosphere by human activities? a) calcium carbonate b) carbonic acid c) carbon dioxide d) carbon monoxide e) organic molecules

c) carbon dioxide

200

The process by which some bacteria use nitrates for their own respiration and release nitrogen back into the atmosphere is a) ammonification b) excretion c) assimilation d) denitrification e) nitrogen fixation

d) denitrification

300

Which of the following is most likely to limit primary production in freshwater lakes? A) Oxygen B) Calcium C) Phosphorus D) Carbon E) Iron

C) Phosphorus

400

Which of the following best helps to explain why phosphorus is often a limiting factor in many ecosystems? a) there is usually a gaseous phase in the phosphorus cycle. b) phosphorus cycles very quickly through environments c) under many conditions, phosphorus forms insoluble compounds mostly found in rocks d) phosphate is not a readily taken up by plants e) there are no anthropogenic sources of phosphorus

c) under many conditions, phosphorus forms insoluble compounds mostly found in rocks

500

In the nitrogen cycle, the primary abiotic nitrogen source is a) the atmosphere b) the ocean c) soil d) nutrients e) plants

a) the atmosphere