Ecology Exam & Quiz Questions

Choose the best definition for evolution

A change in heritable traits of a population over generations

Evolution is

A change in the composition of a population from one generation to the next

The river continuum concept is best described as

A conceptual model that describes expected changes in biological communities over physical changes along the length of rivers

A diagram demonstrating the feeding relationships between species in an ecosystem is called

A connectedness web

Which of these options is an example of macroevolution?

Adaptive radiation of finches on an island leading to the evolution of five distinct species from the original species

____ is the decline or temperature with altitude

Adiabatic lapse rate

Rarefaction is a statistical approach meant to

Allow comparison between samples of very different sizes

What is the difference between alpha and gamma diversity?

Alpha: diversity within one community Gamma: diversity within the region

What is cleptoparasitism?

Animal takes food source away from another

The concept of disturbance is best defined as

Any process that removes biomass from a community

The ultimate source of carbon from which all life is constructed is derived from

Atmospheric carbon dioxide

Which of these statements is TRUE about aquatic vs. terrestrial food webs?

Autotrophs in aquatic food webs have greater rates of production

In a competitive interaction in which species A has a higher carrying capacity than species B, it is expected that species ___ will go extinct

B

Batsian vs. Mullerian mimicry?

Batsian: not actually poisonous, looks like it from color Mullerian: group of similar color poisonous animals

In a famous test of the notion that evolution happens by the inheritance of acquired characteristics, August Weismann maintained a population of mice in his lab for 22 generations. Each generation he measured tail length, randomly chose individuals to be breeders, snipped off the breeders' tails, and then let breeders mate to produce the next generation. Average tail length did not change from the 1st generation to the 22nd. That is, the population failed to evolve. What's the most likely reason the population did not evolve?

Because tail length (that is, the length of tails mice were born with) had negligible influence on which individuals survived to reproduce.

____ refers to the sea floor where the community is strictly heterotrophic

Benthic

Higher than optimal temperatures lead to

Breaking of weak bonds in cell membranes

In a forest understory community, you would be most likely to find plants that use which photosynthetic pathway?

C3

Chemoautotrophs produce energy using

Chemical redox reactions

____ is the tendency of water molecules to adhere to themselves

Cohesion

Metapopulation stability is governed by a balance between extinction and

Colonization

Which of these forms of direct species interactions results in equal (or at least same-direction) outcomes for both species involved?

Competition

Which is the correct order of energy flow for the detrital food chain?

Dead organic matter --> decomposers --> detrivores --> carnivores

If birds with smaller beaks are favored by the environment, it is likely that ____ selection will occur

Directional

The intermediate disturbance hypothesis predicts that

Diversity is maximized at intermediate levels of disturbance

Which of these options is NOT an example of a hypothesis that supports the occurrence of ecological speciation

Ecologically divergent populations should differ in use of signals that relate to mate selection (ecologically divergent pairs of populations should be more reproductively isolated from one another than more ecologically similar pairs of populations, traits that lead to divergent adaptations between populations should lead to reproductive isolation between those populations as well, levels of gene flow between ecologically divergent populations should decrease as populations become more ecologically divergent TRUE)

A/an ____ is defined as an area in space and time that includes both abiotic and biotic components of the environment

Ecosystem

According to Paine, a keystone species

Exerts a top-down influence on lower tropic levels

"Reverse evolution" is a concept that describes when traits evolve to become less complex over time, the opposite direction that evolution should progress in

False

A community is a subset of an assemblage

False

A parasite is a type of pathogen

False

A wolf pack defending an area from other wolves to secure resources is a type of overgrowth competition

False

Condensation of water into clouds is the result of gradual warming of the air

False

Deep-sea vents have no sunlight but are full of life because of the heat venting from the center of the earth

False

Ectothermic organisms that are freeze-tolerant have physiological mechanisms for dealing with ice freezing both within and around cells

False

Fly populations that evolved in a very dangerous environment hit peak fecundity at a later age

False

Food availability is a top-down control on population size

False

Fully saturated soil provides the highest level of available water to plants

False

Grazers and browsers generally consumer all of a plant, this killing it

False

Homeothermic animals require less oxygen when functioning above their basal metabolic rate

False

Intermolecular forces between water are relatively weak

False

Intraspecific competition is competition for resources among individuals of different species

False

Iteroparous species can reproduce only once in their lifetime

False

Larger populations are more likely to become extinct

False

Most populations are restricted in terms of available resources, and therefore grow geometrically

False

Natural selection is the only process that leads to evolution

False

Oligotrophic lakes are characterized as having very high nitrogen content

False

Organisms that are already the most heat tolerant are likely the least vulnerable to increased temperatures as a result of global warming

False

Over successional time, as plants compete with each other more directly, net primary productivity increases

False

Plants actively pump water from their roots to their leaves

False

Plants tend to be smaller, more sparsely distributed and less diverse in warmer, wetter climates

False

Precipitation and evapotranspiration are two examples of inflows in a water budget

False

Primary succession occurs rapidly, following low-intensity disturbances

False

Productivity increases as flooding increases in wetlands

False

Short-wave solar radiation is less energetic than long-wave solar radiation

False

Speciation occurs as the result of either natural selection or due to random processes, but not both

False

Species which are distributed more variably will require fewer samples to accurately describe their population

False

Survivorship curves tend to be consistent within a species

False

Terrestrial environments experience overall less environmental variability than aquatic environments

False

The Lotka-Volterra competition equations predict that species can only coexist stably if INTERspecific competition is stronger than INTRAspecific competition

False

The competitive ability of species remains constant even when environmental conditions change

False

The intrinsic rate of increase in a population tends to increase as population density decreases

False

The more energy an organism allocates to reproduction, the more it can allocate for growth and maintenance

False

Transpiration is the water loss through the roots of plants

False

Tropical forests are highly diverse and productive because they have such nutrient rich soils

False

Water is less dense than ice

False

What are basal species

Fed on by others but does not feed on others

The ____ is the sum of alleles of all individuals in a population and represents the total genetic variation of that population

Gene pool

The addition of what new body of knowledge substantially improved our understanding of evolution?

Genetics

Which of these is NOT one of the three major life history traits used to classify organisms into life history modes?

Gestation period (Number of offspring, age of maturity, juvenile survivorship ARE)

____ are herbivores that specialize on eating seeds

Granivores

An organ demonstrating positive allometry

Grows faster than the rest of the body

A population that has reached carrying capacity

Has a growth rate of zero

Later-successional plant communities tend to

Have higher species diversity

____ are organisms that consume other organisms

Heterotrophs

Turnover and decomposition rates of leaf tissue in savannas are so high because of

High rates of herbivory by large mammals

Photosynthetically active radiation (PAR)

Includes only the solar energy with wavelengths of 400-700nm

Which is an example of an indirect effect

Increasing nutrient levels for a plant causes an herbivore population to increase because its plant food source increases

Aposematic coloration

Indicates that a prey species is toxic

Which of these is NOT an example of a disturbance that could change successional trajectories in a community?

Invasion

Which is considered a plant micronutrient

Iron

As species richness increases in a community, species evenness

It depends, no way to tell from this information

What are the five ingredients that make up soil?

Living organisms, gas, water, minerals, organic matter

____ population growth describes intraspecific competition

Logistic

Soil features that are a dull blue, green, or pale brown are a good indication of

Long periods of saturation

____ weathering of soils results from the action of water, wind and temperature

Mechanical

Mountainous regions of the globe tend to be more arid because

Mountains force air to rise and cool, reducing precipitation

Which of the following can affect changes in genetic variations within populations (choose all that apply)

Mutations, gene flow, natural selection, genetic drift

Which of these forms of species interactions is NOT an indirect interaction?

Mutualism (exploitation competition, habitat facilitation, trophic cascades ARE)

Name the three types of symbiosis

Mutualism, commensalism, parasitism

The ____ in the ocean are the swimming organisms that feed on zooplankton and pass energy to higher tropic levels

Nekton

What is NPP?

Net Primary Production: total primary production minus carbon used by plants

____ is a macronutrient, and is positively correlated with the rate of photosynthesis

Nitrogen/Carbon

What is species richness

Number of species within community

Coral reefs are not found everywhere in the oceans for the primary reason that

Particular salinity and temperature levels are required for coral skeletons to harden and form reef structures

A behavioral adaptation of ectothermic animals to assist in thermoregulating their bodies is to

Physically move between warmer and cooler locations

Which of these factors does NOT help to explain potential differences between maximum and realized fecundity in populations?

Physiological constraints on the number of offspring per female (Population density, food availability, competition between individuals DO)

Which species is considered the "keystone species" in Robert Paine's studies from the 60's?

Pisaster

An environmental stressor that can indirectly affect the amphibians population sizes by reducing growth rates is

Pollutants

Which of these is NOT a major soil process, driven by the availability of water?

Precipitation (gas exchange, percolation, root exudation ARE)

Soil water content increases when

Precipitation increases

It is the lack of ____ that is the distinctive characteristic of all deserts

Precipitation/rain/moisture/rainfall

Which of these is an example of density-dependent factor in populations?

Predation

Which of these is NOT an example of an abiotic limit to species distribution

Predation (Temperature, water availability, oxygen availability ARE)

Which of the following are body form adaptions stream animals have made to living in fast flow environments? (choose all that apply)

Protective cases, stream-lined, sticky undersurfaces, flattened and broad

Qualitative vs. Quantitative defense compound in plant defense?

Qualitative: what plant lays down to be poisonous Quantitative: builds up in predator over time

What would you expect r to be for a population of dolphins that is observed for many years in the same place?

R > or = to 0

Which zone in coral reefs is the harshest environment for organisms?

Reef crest

When an organism begins to be challenged by a change in the environment, the first characteristic of their life history to suffer is

Reproduction

The core trade-off at the heart of iteroparity vs. semelparity is that of

Reproduction vs. survival

Life history seeks to understand how organisms allocate resources towards growth, survival and reproduction to optimize

Reproductive success

Adaptive radiation

Results in new specialized species

Consider the three plots of age-distribution. Which population is decreasing?

Right (age pyramid that is smaller at the bottom compared to middle)

Which part of the plant is most effective at absorbing water?

Root hairs

When plants experience a shortage of water, they tend to put energy into growing

Roots

____ competition occurs when growth and reproduction are depressed equally across individuals as competition intensity increases

Scramble

The progressive decline in density and increase in biomass of remaining individuals in a population is known as

Self-thinning

____ is the mode of reproduction in which an organism expends all of its energy in one suicidal act of reproduction

Semelparity

Population divergence occurring as a result of females in a species consistently choosing males of a particular color is an example of

Sexual selection

What is a guild

Species that use a common resource in a similar way

Which of these is an autotroph?

Sycamore tree

Which of these organisms is an example of an endoparasite

Tapeworm

The three basic types of survivorship curves differ based on

The distribution and timing of mortality events in a population

The E soil horizon is characterized by

The loss of materials such as clay or aluminum to other layers

Thermal neutral zones are best described as

The range of temperatures during which endothermic base metabolic rates are constant and minimal

Transpiration efficiency in plants is measured as

The ratio of photosynthesis to transpiration

When describing selection on a genomic level, using the concept of genomic islands, "sea level" is a metaphor for

The threshold at which genetic divergence is significantly greater than what would be predicted from neutral evolution alone

Biodiversity is (choose all that apply)

The variety of forms of life on the planet, the number of species co-occurring in a certain habitat

In a lake, the____ is the region of the vertical depth profile where water temperature declines most rapidly

Thermocline

Estuaries are physiographically classified based on

Topography characteristics and the openness of the mouth of the estuary

Which list of terrestrial biomes is in the correct order of most to least precipitation?

Tropical forests, grassland, desert

Which of these biomes has the most stable levels of precipitation throughout the year?

Tropical rainforest

A "Darwinian demon" is an organism that maximises all life history traits at once

True

A sex ratio favoring females often leads to more rapid population growth

True

A trophic cascade is an example of an indirect effect

True

All else being equal, alleles associated with higher reproductive success increase in frequency more so than other alleles

True

Altering the growth-limiting factor in the environment can alter the carrying capacity of a population

True

Although Paine's original work on keystone species was focused on predators, any species that plays a disproportionately large role in maintaining coexisting populations of other species can also be considered a keystone species.

True

An animal cannot produce essential amino acids. They must be acquired via consumption

True

An assumption of the competitive exclusion principle is that environmental conditions must stay relatively constant

True

An individual's fitness is determined by the number of offspring it produces that survive to reproduce

True

Biological, physiological and ecological traits are all subject to allometry, or scaling relationships

True

Climate is primarily determined by long-term patterns of temperature and precipitation

True

Coevolutionary patterns in predator-prey and herbivory interactions are very similar

True

Cold water holds more oxygen than warm water

True

Exploitation competition occurs when species indirectly interact with one another but affect the availability of shared resources

True

Flooding is an example of a density-independent factor that can regulate populations

True

Grasslands are more common than forests in areas prone to drought

True

Grasslands are more common than forests in areas prone to fire and drought

True

Homeothermic animals have more stable internal temperatures than ectothermic animals

True

In the snowshoe hare population experiment run by Krebs and colleagues, food availability and predation interacted to impact hare populations

True

Inbreeding can lead to lower fitness

True

Increased rates of photorespiration reduce net photosynthesis in plants

True

Increasing the salinity of ocean water, while maintaining the set temperature makes the water more dense

True

Insect populations developing resistance to pesticides in an example of microevolution

True

Light compensation point is the amount of light a plant receives where the rate of net photosynthesis is zero

True

Low juvenile mortality favors later maturity, and maturity at a larger size

True

Modern researchers who study succession see it as a less orderly and more dynamic process than early successional theorists did

True

More diverse communities are generally less variable and more resilient to disturbance

True

Most populations of microorganisms have a growth rate very similar to exponential growth

True

Plants carry out respiration both during the day and at night

True

Polyploid individuals in a population have more copies of chromosomes than expected

True

Roots comprise a greater proportion of net primary production in an ecosystem than their proportion of overall standing biomass

True

Seasonal climatic variation can have a strong impact on soil profile formation

True

Semelparity is a life history strategy that agriculture commonly selects for, because semelparous crops generally provide higher yields

True

Silt particles are larger than clay particles, but smaller than sand particles

True

Species diversity generally increases when habitat heterogeneity increases

True

Stream flow rates and stream bed forms are strongly impacted by landscape slope

True

Switching to a less preferable source of food is a common response to drops in abundance of preferred foods, and complicates predator-prey interactions

True

Sympatric speciation occurs when populations overlap geographically but still diverge genetically

True

The concept of "climax" in succession is most tightly linked to the "super-organism" concept of succession

True

The same amount of total primary production occurs on land as in the world's oceans

True

Wetlands are highly productive ecosystems

True

When experimental treatments have a strong effect, fewer data replicates are necessary to make statistical conclusions

True

What is coevolution

Two species evolve at the same time in reaction to each other

Which survivorship curve likely describes mammals?

Type 1 (High and steady then drops)

A ____ population distribution pattern results from negative interaction among individuals

Uniform

A reaction norm describes

Variation in response to the environment of a single genotype

What is the most important limiting abiotic factor to plant growth?

Water

Water is an excellent solvent for many chemicals because

Water molecules are polar

When a population is growing logistically, at which stage is the change in population size (N) over the change in time (t) i.e. dN/dt the greatest?

When N is half the size of K

Two scientists, M. Dash and A. Hota (Sambalpur University, Orissa, India), studied the effect of population density on growth and development of tadpoles (Rana tigrina). The results for the mass of the tadpoles at metamorphosis vs. density is given in the plot. Is competition occurring?

Yes

A population that has reached carrying capacity has reached a growth rate of

Zero

Which of the following mechanisms of competition could NOT occur between ground-dwelling rodents?

allelopathy

Photosynthesis by phytoplankton primarily occurs in the ____ zone of lakes

epilimnion

In ____ population size increases without limits

exponential growth

Fly populations that evolved in a very dangerous environment

lay more eggs, sooner

Which of these conditions is NECESSARY to the definition of a population

members of a population interbreed

Biomass is a direct measure of

population structure at a given time

In the Lotka-Volterra competition model below, which term describes the per-capita effect of Species 1 on Species 2's population dynamics?

α21