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

12. Populations and Communities
Interactions Among Living Things

13. The Theory
Natural Selection – individuals who have the best characteristics are more likely to survive and produce offspring
Charles Darwin – (1809 – 1882) father of evolutionary biology

14. A Place in the World
Adaptations – a physical characteristic that helps an organism live in an area
Example: cacti in the desert
Niche – the role of an organism in its habitat, or how it makes its living
type of food I eat
Who else eats you
Whether you need to survive

15. The Fight
Competition – the struggle (fight) between two organism to get the same thing

16. Let’s Eat! Predation – when one organism kills another for food
Predator – dominant organism
Predator Adaptations – help them catch and kill their prey
Prey – inferior organism
Prey Defense Strategies – certain adaptations to prevent being killed by predators
Skunk, poison ivy, porcupines

17. Relationships Mutualism – both species benefit
Example – hippo and bird
Commensalism – one species benefits and the other is neither helped nor harmed
Example – clown fish and sea anemone
Parasitism – one species is benefited and the other is harmed. Doesn’t kill because it needs the host to live
Example – head lice, ringworm, tape worm, ticks

18. Relationship
Species One
Species Two
Mutualism +
Commensalism O
Parasitism -

19. Populations and Communities
Changes in Communities

20. Primary Succession Where no soil or organisms exist
Example: rocks after volcano erupts or glaciers
Pioneer Species – the very first organisms that inhabit an area
How do they get there?
wind, water, other organisms carry them
What are they?
Lichens and moss

21. Secondary Succession
A series of changes in an area where the ecosystem has been disturbed, but the soil and organisms still exist
Example – tornadoes, hurricanes, fires, logging, and farming
Faster rate of succession

22. Succession Diagram