LS 7B Week 10

How many "cells" of circulating air are found around the Earth?

6

Biological reserves are an important tool in maintaining biodiversity because a reserve:

that is designed for a single species will also protect other species in the reserve.

Most climate models predict that, during the 21st century, mean global temperature will increase by:

2-5

What is the approximate size of the human population today?

7 billion days

keystone species

A species that influences the survival of many other species in an ecosystem disproportionately on many trophic levels

Tropical rainforests have high species richness of trees. Which of the following statements provides the MOST reasonable explanation why animal species richness is also high in tropical rainforests?

Animals have diversified into the vast number of niches provided by tree diversity.

In general, what is the relationship between a country's ecological footprint and its overall standard of living?

As the standard of living increases, so does the ecological footprint.

Nutrients from croplands are carried by the Mississippi River into the Gulf of Mexico. If nutrients are good for growth, why are scientists concerned about this nutrient influx?

Higher productivity may result in increased respiration on sinking algal material, depleting oxygen within gulf waters.

Which of the following statements about coral bleaching is TRUE?

Increased seawater temperature is one cause of coral bleaching. Bleached corals die more rapidly than unbleached corals. Coral bleaching results from the loss of algal symbionts from the coral tissue. Corals appear white after bleaching because their white calcium carbonate skeletons are visible through their translucent tissue.

Which of the following statements is TRUE regarding the process of eutrophication?

It can result in "dead zones" devoid of aquatic animal life.

Why are microorganisms like fungi, bacteria, and archaeons so important to the carbon cycle?

Many of these microorganisms generate carbon dioxide, making it available for primary producers

So-called "dead zones" in coastal oceans are associated with nutrient runoff and oxygen-depleted bottom waters. What causes the oxygen depletion?

Nutrient runoff causes algae and cyanobacteria populations to grow. When they die, they are consumed by heterotrophic bacteria that consume oxygen via aerobic respiration.

Which of the following statements explains how an oxygen-rich atmosphere was possible?

Rates of oxygen consumption were lower than rates of photosynthesis

If Earth had no oceans, would temperatures at the equator be hotter or colder than they are now?

Temperatures would be hotter.

A group of scientists in Alaska notices that not only have atmospheric CO2 levels increased at their sampling site but so too have methane levels. What most likely accounts for this increase in methane levels?

The release of methane from thawed permafrost.

Biologists who study biodiversity describe new species and monitor species of which we are aware. Why is the study of biodiversity important in the Anthropocene?

The study of biodiversity is important because it helps quantify the effects of human actions on changes in the traits of many populations (size, density, distribution).

Many endangered species of birds in Hawaii are in danger of contracting avian malaria from mosquito bites. Many of these bird species live in the higher elevations of mountains in Hawaii, where it is too cold for the mosquitoes to exist. If global warming continues at the current estimated pace, what would you expect to happen to the distribution of these bird species?

Their distribution will decrease to areas of even higher elevation.

Rainforests have high tree species richness, but low density. In deciduous forests the pattern is the opposite. Which of the following is NOT a plausible explanation for this pattern?

There are fewer species in temperate regions because the number of trees per hectare is lower than in tropical rainforests.

As you hike from the base of a mountain to the top of a mountain, you would expect see decreasing levels of biodiversity.

True

If all other aspects of their lifestyles were equivalent, a vegetarian would have a smaller ecological footprint than someone who consumes a large amount of meat.

True

Some biologists believe that the latitudinal gradient in species diversity reflects the fact that high latitudes recently lay beneath large glaciers. If there had been no recent ice age, would we still expect to see a latitudinal diversity gradient?

Yes, with or without recent glaciation of high latitudes, there is still less energy available at high latitudes to support diverse biomes.

Which of the following statements reflects an evolutionary change that is in line with the Red Queen hypothesis?

a species of beetle that has two new mutations that confer resistance to an insecticide

An individual's ecological footprint is equivalent to the:

amount of land required to provide all the resources used by that individual.

If a scientist wanted to determine if a forest environment had been polluted, which of the following groups of organisms typically would be the BEST indicator for the presence of pollutants?

amphibians

On land, _____, which are broad, ecologically uniform areas, are recognized by their characteristic vegetation that reflects adaptation of form and physiology to climate.

biomes

Autotrophs remove _____ from the air and fix this into tissues providing _____ for secondary consumers.

carbon dioxide; energy

In addition to burning fossil fuels, humans return CO2 to the atmosphere faster than it can be removed by:

clearing forests for agriculture

Sustainable development plans are designed to allow:

conservation of species used by humans without causing the decline or extinction of that species.

The high specific heat of water means that land masses near the equator are:

cooler than predicted because of all the heat carried by ocean waters from low to high latitudes.

Moderate temperatures and precipitation, as well as nutrient-rich soil due to annual leaf fall, characterize this biome.

deciduous forest

In terrestrial ecosystems, nitrogen is returned to the atmosphere by:

denitrifying bacteria.

Which of these biomes receives the least amount of rainfall, and therefore has low primary production, nutrient-poor soil, and plant species that are adapted for water-storage?

desert

In deeper waters, nutrients primarily come from:

detritus from more productive shallower waters.

Increased phosphate levels in the Everglades has led to

displacement of native plants by phosphate-loving introduced plants.

In marine ecosystems phosphorus is added to the ecosystem primarily from:

erosion of rocks on land.

Nitrogen runoff leads to large increases in the populations of algae and cyanobacteria in lakes and oceans in a process known as:

eutrophication

If all of the tertiary consumers were removed from an environment, the associated food web (and thus the carbon cycle) would collapse.

false

Most of Earth's primary production comes from tropical rainforests.

false

In which of the following regions would you expect to find river biomes with HIGH levels of oxygen in the water?

fast-moving, clear-water rivers in the Rockies

Genetic variation within species is important to conservation because:

genetic variation provides material for natural selection to "act upon" in changing environments.

why is atmosphoric carbon important?

greenhouse gases ensure warmth stays in the atmosphere

threats to biodiversity?

habitat loss, pollution, introduced species, over exploitation, climate change

A dead zone has been documented off the coast of Oregon. Which of the following could contribute to the formation of the dead zone?

high nitrogen levels in the area

Remember that, as a rule, temperatures decrease with an increase in altitude. If you were studying the effects of climate change on the geographic ranges of species living in the mountains and your climate records showed that mean temperatures were increasing, you would predict that species ranges would show a shift toward:

higher elevations.

If phosphorus concentrations were to suddenly increase in a marine ecosystem, which of the following would likely occur?

increased primary productivity

very common, well-established species of grass. Further research shows that this grass is native to an area in another part of the world. This species of grass would be classified as a(n) _____ species

invasive

Warm air is _____ dense than cold air, and warm air holds _____ moisture than cold air.

less; more

Given models of population growth, which model would be the BEST to use for determining estimated sustainable yield?

logistic

species diversity is generally greatest at?

low lats and decreases towards high lats

Ultimately, the nitrogen cycle is dependent on:

microorganisms that convert atmospheric N2 into usable forms.

In either freshwater or marine biomes, which regions would you expect to have the HIGHEST productivity?

near the surface where sunlight penetrates

Some biologists have suggested that overexploitation in the harvesting of some sharks (i.e. top predators) has caused drastic changes in marine communities. Which of the following would you expect after removal of a top predator from a community?

population growth of prey species

Which of the following organisms can incorporate atmospheric carbon directly into C6H12O6, thereby playing a major role in a food web?

primary producers

Eutrophication describes the:

process in which added nutrient levels lead to the growth of algae and cyanobacteria populations, eventually causing oxygen availability to decline.

first to arrive after disturbance?

r then k cause need stable ecosystem

What is one "low-tech" method currently available to actively remove CO2 from the air?

reforestation of previously cleared landscapes

Decomposers are vital components of a food web because they:

return carbon (as CO2) to the atmosphere.

disturbance to

succession

Which of the following factors likely contributed to the accumulation of O2 within Earth's atmosphere?

the fact that there is a slight "de-coupling" between photosynthesis and respiration the fact that photosynthesis releases O2 as a product the fact that oxygen is also cycled during the carbon cycle the evolution of cyanobacteria

The hypothesis that species diversity is greater at lower latitudes than higher latitudes because low-latitude habitats are older would be supported if speciation rates were:

the same at high and low latitudes.

Increased overfishing on predators of crown-of-thorns starfish is likely to result in continued increase in crown-of-thorns starfish population sizes.

true

The evolution of biodiversity on the planet can be linked to patterns in the carbon cycle over time.

true

This biome is the coldest, with the lowest biodiversity and a permanent layer of ice beneath the soil.

tundra