Populations and Communities Living Things and the Environment
A little vocab… Ecology - the study of how organisms interact with their environment Organism - a living thing Habitat - the specific environment that provides the things an organism needs to live, grow, and reproduce
Living or Nonliving? Biotic Factor - living parts of a habitat Examples - flowers, worm, frog Abiotic Factor - nonliving part of a habitat Examples - water, sunlight, oxygen
The Line-Up Species - group of organisms that mate and reproduce Population - all members of one species in a particular area Community - all different populations that live in an area Ecosystem - a community including its surrounding environment (abiotic factors)
Populations and Communities Studying Populations
Types of Observations Direct Observation - counting all individuals by ones Indirect Observation - counting the “signs” of an individual
Methods of Study Sampling - taking an estimate of a type of organism in an area Mark-and-Recapture Studies - catch an organism, mark it, then release
Population Fluctuation Birth Rate - # of births in a population during a specific time Death Rate - # of deaths in a population during a specific time If birth rate is > than death rate, then population is ____________ If birth rate is < than death rate, then population is ____________
Population Fluctuation Immigration - organisms moving into a population Emigration - organisms moving out of a population Population Growth Equation: (B - D) + (I - E) = N *If N is a positive #, the population is increasing
Population Fluctuation Population Density - # of individuals in a specific area Population Density Equation: # individuals Unit area
Population Factors Limiting Factor - an environmental factor that causes a population to decrease Examples: food and water, space and weather Carrying Capacity (K) - the largest population that an area can carry