1. Populations and Communities
Living Things and the Environment

2. 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

3. 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

4. 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)

5. Populations and Communities
Studying Populations

6. Types of Observations
Direct Observation - counting all individuals by ones
Indirect Observation - counting the “signs” of an individual

7. 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

8. 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 ____________

9. 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

10. Population Fluctuation
Population Density - # of individuals in a specific area
Population Density Equation:
# individuals
Unit area

11. 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