Ecology Flashcards
Define: Ecology, population, community, ecosystem
Ecology: The study of the relationships between organisms and their environment.
Population: A group of individuals of the same species that occupy a given area at the same time and share a unique set of genes.
Ecosystem: Biological communities coupled with their abiotic environment.
Describe the factors that contribute to exponential growth of a population.
Factors such as, number of offsprings, likelihood of survival to reproductive age, the duration of the reproductive period, length of time it takes to reach maturity.
Define carrying capacity.
The maximum population size that an environment can support.
Keystone species
A species that is of overriding importance in a community and controls the community’s characteristics.
Define survivorship curves and distinguish between type I, II and III species in terms of the probability of death during their lifetime.
Survivorship curves are graphs that show the proportion of a population that survives from one age to the next.
Type 1(convex) populations survive to an old age, and then die rapidly.
Type 2(diagonal) populations have constant probability of death through their lives.
Type 3(concave) populations experience very high juvenile mortality.
Distinguish between density independent and density dependent factors and recognize examples.
Density-dependent factors: Environmental parameters that are more severe when population density is high (or sometimes very low) than they are at other densities. Disease, predation, and parasitism are density-dependent factors.
Density-independent factors:
Environmental parameters that influence the number of animals in a population without regard to the number of animals per unit space (density). Weather conditions and human influences often have density-independent effects on animal populations.
Heterotrophs
Organisms that obtain both inorganic and organic raw materials from the environment to live. Animals, fungi, many protists, and most bacteria are heterotrophs. Heterotrophs are the organisms that are not able to synthesize their own food. Thus, they are dependent on other organisms for food. Animals depend on plants or other animals for food. Hence, they are heterotrophs.
Define aposematic coloration and cryptic coloration and recognize examples
Aposematic Coloration: Sharply contrasting colors of an animal that warn other animals of unpleasant or dangerous effects (e.g., contrasting colors of a Venomous snake, or white stripes of a skunk). Cryptic Coloration: Camouflage, also called cryptic coloration, is a defense or tactic that organisms use to disguise their appearance, usually to blend in with their surroundings (e.g., Goldenrod Crab Spider blending into a yellow flower)
Describe how predator and prey organisms coevolve
When a change toward greater predator efficiency is countered by increased elusiveness of prey.
Define the different symbiotic relationships: commensalism, mutualism, parasitism and recognize examples
Commensalism: Living within or on an individual of another species without harm. The commensal benefits, but the host is unharmed.
Mutualism: A relationship between two species that benefits both members. The association is necessary to both species.
Parasitism: A relationship between two species in which one-member (the parasite) lives at the expense of the second (the host).
Distinguish between the intermediate and definitive host of a parasite
Definitive hosts are organisms that harbor parasites until the completion of their life cycle.
On the other hand, intermediate hosts are those that harbor asexual parasites until they move on to the definitive host for sexual reproduction.
Define food chain
A linear sequence of organisms through which energy is transferred in an ecosystem from producers through several levels of consumers.
Describe how energy enters and moves through the food chain and is lost at each step.
Primary producers use energy from the sun to produce their own food in the form of glucose, and then primary producers are eaten by primary consumers who are in turn eaten by secondary consumers, and so on, so that energy flows from one trophic level, or level of the food chain, to the next.
Biomass
The total mass of all organisms in an ecosystem.
