Environmental Science Chapter 8 Review Populations -same species, same place/time, interbreed -density = # of individuals per unit area -dispersion – even, clumped, or random -described by size, density, and dispersion Reproductive potential -bacteria have high reproductive potential - elephants low at 21 months - breeding season – give birth during specific time of year when food is available.

Environmental Science Chapter 8 Review Reproducing earlier in life has the greatest effect on reproductive potential. The maximum number of offspring each individual can produce will limit a population’s biotic potential. Generation time – the average age at which members of a species reproduce.

Environmental Science Chapter 8 Review Exponential growth - Occurs in nature only with plenty of food/space - Logarithmic growth, or #s increase rapidly Carrying Capacity -Maximum population that ecosystem can support indefinitely. -determined by the supply of the most limited resources.

Environmental Science Chapter 8 Review Population’s growth rate is its birth rate minus its death rate. Competition – members of a population use the same resources in the same ways, so eventually compete with each other. Population regulation -density dependent-predation, diseases, resources -density independent-severe weather, nat.disasters

Environmental Science Chapter 8 Review Niche – includes species home, environmental factors for survival, and interactions with other organisms. Competition -different individuals using the same limited resource. -cannot occur between animals from two different ecosystems. -a type of interaction in which both are harmed since each has less access to the resource. -niche’s overlap

Environmental Science Chapter 8 Review Predation - predator = lynx, prey = hare - predator usually kills and eats its prey Parasitism – lives in or on another organism - intestinal worms, ticks, mistletoe on a tree Mutualism – benefit to each for survival - bacteria in cows stomachs - bats and flowers - termites and protozoa

Environmental Science Chapter 8 Review Commensalism – neither harmed, one may benefit - orchids in trees Symbiosis – two organisms live in close association such as mutualism and commensalism. Coevolution – over long time, two species develop adaptations that benefit both of them.

Environmental Science Chapter 8 Review Populations change – grow, shrink, remain the same. An organism’s habitat is a location. If 2 species use the same food source, or territory at different times, they are indirect competitors.

Environmental Science Chapter 8 Review Short answers Predict what might happen to the population of rabbits and coyote if the rabbits exceed the carrying capacity of the environment. Explain how two species can compete for the same resource even if they never come into contact with each other.

Environmental Science Chapter 8 Review Essays Zebra mussels were accidentally imported to the Great Lakes from Europe and have no natural enemies in the US. They have multiplied rapidly clogging water intake pipes, marine engines, etc. How could zebra mussels be eliminated from the Great Lakes?

Environmental Science Chapter 8 Review Essays Viruses are the cause of many infectious diseases, such as common colds and flu. Under what conditions do you think viral diseases will spread most rapidly between humans? What can be done to slow the spread of these viruses?