TEST Review - Chapter 4-5 Environmental Science

What is the difference between a food web and a food chain?

A food web consists of many food chains. A food chain only follows just one path as animals find food. eg: A hawk eats a snake, which has eaten a frog, which has eaten a grasshopper, which has eaten grass. A food web shows the many differentpaths plants and animals are connected.

What is an organism's habitat? What are resources?

A habitat is a place where an organism makes its home. A habitat meets all the environmental conditions an organism needs to survive. For an animal, that means everything it needs to find and gather food, select a mate, and successfully reproduce. ... The main components of a habitat are shelter, water, food, and space.

What are survivorship curves?

A survivorship curve is a graph showing the number or proportion of individuals surviving to each age for a given species or group (e.g. males or females). ... They are typical of species that produce few offspring but care for them well, including humans and many other large mammals.

What is the difference between biotic factors and abiotic factors of an ecosystem. Give at least 3 examples of each!

Abiotic factors are the non-living things of an ecosystem; Biotic factors comprise of the living things of an ecosystem. Examples of the abiotic factors are sunlight, temperature, energy, the wind, water, soil, etc., whereas plants, trees, animals, microorganisms, etc.

What is biotic potential?

Biotic potential is the ability of a population of living species to increase under ideal environmental conditions - sufficient food supply, no predators, and a lack of disease. Need to know both factors that determine an organism's biotic factor and that is the rate of reproduction and size of each litter.

Limiting factors are divided into density-dependent factors and density-independent factors. Define each one, and give 2 examples of each.

Density-dependent limiting factors cause a population's per capita growth rate to change—typically, to drop—with increasing population density. ... Density-independent factors affect per capita growth rate independent of population density. Examples include natural disasters like forest fires.

What is population distribution? List and describe the three types of population distribution. Why would organisms be dispersed into each of these three ways?

Dispersion or distribution patterns show the spatial relationship between members of a population within a habitat. Individuals of a population can be distributed in one of three basic patterns: uniform, random, or clumped.

Define the following...immigration, emigration, migration

Emigrate means to leave one's country to live in another. Immigrate is to come into another country to live permanently. Migrate is to move, like birds in the winter. The choice between emigrate, immigrate, and migrate depends on the sentence's point of view.

Explain how a sudden change in environment - either through a disaster or through shifts in conditions - might affect the evolution of species in the area.

Environmental change and isolation of groups of organisms play an important role in evolution. ... Change in an organism's environment forces the organism to adapt to fit the new environment, eventually causing it to evolve into a new species.

What is population density? How is it determined?

In biology, populations are groups of individuals belonging to the same species that live in the same region at the same time. Population density is a measure of the number of organisms that make up a population in a defined area.

Define the following terms...evolution, gene, gene pool

In evolutionary science, the term gene pool refers to the collection of all available genes that are available to be passed down from parents to offspring in the population of a single species. The more diversity there is in that population, the larger the gene pool.

What is secondary succession?

It is what follows when a disturbance changes a community without removing the soil

List and describe the 5 main levels of ecological organization.

Levels of organization in ecology include the population, community, ecosystem, and biosphere.

Explain the difference between mutualism and commensalism, with examples.

Mutualism represents a symbiotic relationship where both species involved benefit from the relationship. ... Therefore, the major difference between mutualism and commensalism is that both organisms benefit in mutualism while only one organism benefits in commensalism but the other one is not affected.

What is the equation for calculating population growth?

Net reproductive rate (r) is calculated as: r = (births-deaths)/population size or to get in percentage terms, just multiply by 100. the population is so much bigger, many more individuals are added. If a population grows by a constant percentage per year, this eventually adds up to what we call exponential growth.

What causes evolution (change) of species?

New traits can also come from transfer of genes between populations, as in migration, or between species, in horizontal gene transfer. Evolution occurs when these heritable differences become more common or rare in a population, either non-randomly through natural selection or randomly through genetic drift.

What are invasive species?

Non-natives that overrun native species in ecosystems

What factors determine population growth?

Population growth is based on four fundamental factors: birth rate, death rate, immigration, and emigration.

List the five levels of organization, from the smallest to the largest, that an ecologist studies.

The 6 different levels of organization that ecologists commonly study are species, population, community, ecosystem, and biome.

What are age structure diagrams? What do they show?

The age structure (which is the proportion of population in each age class) of a population affects current and future birth rates, death rates, and growth rates; our impact on the environment; and current and future social and economic status.

What happens to energy as we move from the bottom of the energy pyramid

The amount of energy at each trophic level decreases as it moves through an ecosystem. As little as 10 percent of the energy at any trophic level is transferred to the next level; the rest is lost largely through metabolic processes as heat.

What is the difference between exponential growth and logistic growth? Sketch a graph of each.

The biggest difference, however, is that the line in the logistic growth graph changes direction and begins to level off as it nears the carrying capacity. That means that the main difference between exponential and logistic growth is that logistic growth takes into account carrying capacity.

A disaster wipe out 50 percent of a small population of birds. Prior to the disaster, about half the birds had a green wing patch and half had a blue wing patch. Several generations after the disaster, only 1o percent have a clue wing patch, and 90 percent have a green wing patch. What do you infer happened, and why?

The bird population experienced genetic drift as the result of a sudden catastrophe. The disaster reduced genetic diversity in the population and changed the proportion of birds with a green wing patch vs. a blue wing patch.

What is carrying capacity?

The carrying capacity of a biological species in an environment is the maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water, and other necessities available in the environment.

Define the following: artificial selection, speciation, extinction

The extinction of one species due to the dominance of another. The manipulation of alleles to produce offspring with lower fitness levels. 4. Artificial selection solely concerns the selection of certain genetic mutations which affect the appearance, resistance to disease, and/or productivity of a species

Explain why a food web is a better representation of energy flow in a community than a food chain.

The food web provides a better model of an ecosystem because the food web is a model between MANY different consumers and producers in an ecosystem. While the food chain is a model for just one consumer and producer. ... Because energy is lost as it moves from producers to consumers, the bottom level is the largest.

What causes (in logistic growth) a population to slow (or stop) its growth?

The population size is approaching the carrying capacity. ... As populations increase environmental resistance causes the growth rate to slow down, until carrying capacity is reached.

What is the difference between producers and consumers?

The producers generate food for themselves and others; consumers do not produce anything, instead eating producers, other consumers or both. Organisms that eat only producers (i.e., plants) are called herbivores. Animals that eat only consumers (i.e., meat) are called carnivores.

Pronghorn are a species of extremely fast hoofed mammal that live on the plains of western North America. They are so fast that no current North American predator can catch them. During the ice age, cheetahs occupied North America. Speculate about how pronghorn became so fast.

The pronghorn had to evolve to become fast to avoid becoming extinct from the cheetahs.

What happens to the number of organisms as we move from the bottom to the top of the energy pyramid?

The pyramid of energy shows that the variety and number of species decreases as you move to higher trophic levels. ... This is also assuming that the organisms of the higher trophic level only eat the one organism. To maintain energy levels, higher organisms must eat more food than those at the lower levels.

What is an organism's niche? What causes it to change?

The term niche, when used in the science of ecological biology, is used to define an organism's role in an ecosystem. Not only does its niche include the environment that a given organism lives in, but it also includes the organism's "job" in that environment.

Explain at least two ways that ecologists determine population of an organism in an ecosystem.

Two important measures of a population are population size, the number of individuals, and population density, the number of individuals per unit area or volume. Ecologists estimate the size and density of populations using quadrats and the mark-recapture method.

Define...mutation, migration, genetic drift, and natural selection

Typically, mutations increase genetic diversity; the other three processes reduce it. Natural selection and genetic drift tend to enhance genetic differences among populations; migration tends to homogenize genetic difference, decreasing the differences among populations.

What are keystone species?

a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.

What are adaptations?

inherited characteristics of organisms that enhance their survival and reproduction in specific environments

What is primary succession?

the initial development of plant or animal communities in an area where no soil initially exists such as after a volcanic eruption or the scraping of the surface from a glacier

What do herbivores eat? Carnivores? Omnivores? Detritivores? Decomposers?

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Define the following in terms of an organisms niche: tolerance, competition, resource partitioning, character displacement, predation, coevolution, parasitism, symbiosis, herbivory, mutualism, commensalism

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