CLEP BIOLOGY 2023/2024 Study Guide

Ecology - -The study of how organisms interact with one another and with their physical environment - Organism -> population -> community -> ecosystem -> biosphere - Binomial: scientific name Biotic Abiotic - - Biotic: living, or once living, factor in an ecosystem - Abiotic: non-living factor in an ecosystem Organisms Species Population - - Organisms: an individual living thing - Species: a group of similar organisms that can mate and produce fertile offspring - Population: A group of individuals that belong in the same species and live in the same area Community Ecosystem Biosphere Biodiversity - - Community: all the populations of all the different species that live together in a particular area - Ecosystem: all the organisms that live in a place, along with their physical environment - Biosphere: all of the ecosystems on Earth - Biodiversity: the variety of organisms in an ecosystem Demography - - Demography: the statistical study of populations and how they change over time (population: all organisms of a given species that live in a particular area) - Population size: number of individuals - Population density: number of individuals per unit area of volume - Population size and density estimated using quadrats and the mark-recapture method - Quadrats: good for immobile organisms like plants; each quadrat marks off area of same size with in habitat; number of individuals in quadrat counted; process completed for multiple quadrat areas in random locations in habitat and averaged together - Mark-recapture method: organisms that move around; capturing sample of animals, marking in some way, release organisms; later, new sample collected with some that are marked and some unmarked; ratio of marked to unmarked helps scientists estimate how many individuals in total population - Organisms in a population may be distributed in a uniform (population evenly spaced), random (random spa Population Population ecology Population size (N) - - Population: a group of individuals that belong in the same species and live in the same area - Population ecology: the ecological study of how biotic (living) and abiotic (non￾living) factors influence the density, dispersion, and size of a population - Population size (N): the number of individuals in the population Density Density-dependent factor Density-independent factor - - Density: the number of individuals per unit area or volume (ex 100 deer per acre of land in a forest) - Density-dependent factor: referring to any characteristic that changes population size (N) because it is affected by population density (ex: competition for resources, predation, disease) - Density-independent factor: referring to any characteristic that changes population size (N) because it is not affected by population size (ex natural disasters) Dispersion Carrying capacity Exponential growth Logistic growth - - Dispersion: the pattern of spacing among individuals within the boundaries of a population - Carrying capacity (K): the max population size (max N) that can be supported by the available resources in an environment - Exponential growth: growth of a population in an ideal, unlimited resources environment - Logistic growth: leveling off on exponential growth due to limiting resources Life tables Survivorship curves Age-sex pyramid - - Life tables: summarize birth and death rates for organisms at different stages of their lives - Survivorship curves: graphs that show what fraction of a population survives from one age to the next; type one is when organisms tend not to die when they are young or middle aged but when they are elderly (like humans and most primates) and have few offspring and provide lots of care to make sure those offspring survive; type two dies equally at each age interval (ex birds) and may have few offspring and provide lots of care to them; type three is when very few offspring survive younger years but those who survive live long (invertebrates and most fish), and each has lots of offspring but do not provide much care - Age-sex pyramid: a "snapshot" of a population in time showing how its members are distributed among age and sex categories, can help predict population growth/shrinkage; sharp pyramid for countries with rapid population growth because lots of young people, common in economical Life history - - Life history: the pattern of survival and reproduction events typical for a member of the species (ie lifecycle); patterns evolve by natural selection and