1. Chapter 8 pg 210 Understanding Populations

2. What is a population?  “all the members of a species living in the same place at the same time”

3. Properties of Populations 1. Density - “the number of individuals per unit area or volume” Ex - # bass fish per cubic meter of water 2. Dispersion – “ the relative distribution or arrangement of it’s individuals in a given amount of space” “ the relative distribution or arrangement of it’s individuals in a given amount of space”  Even  Clumped  Random

4. Growth Rate  Change in pop. size = Births – Deaths Births – Deaths If adults in a population are not replace by new births, the growth rte will be negative and the population will shrink

5. How Fast can the Population Grow?  Biotic Potential = Fastest rate at which its population can grow. Limited by: The organism’s: Repro. Potential

6. Reproductive Potential 1. Number of offspring produced at one time 2. How often does the organism reproduce 3. how soon can the organism reproduce (age!?)

7. Exponential Growth  Population growth that grows faster and faster!  Produces a J- Shaped curve

8. Limits to population Growth  1. Carrying Capacity  2. Resource Limits  3. Competition within a population

9. 1. Carrying Capacity  Defined as the maximum population (number) that the ecosystem can support.  Will crash when it reaches capacity due to disease, etc.

10. 2. Resource Limits  A particular resource that is consumed by a particular species (food, water, etc) is called a “LIMITING FACTOR”  CC is reached when the species is consuming it at the same rate it is being produced.

11. 3. Competition Within a Population  = Members of a population use the same resources in the same way so they will eventually compete with one another as the population approaches it carrying capacity.  Ex = Christmas time and Limited toys and Limited toys

12. 2 types of Competition: Direct = direct fighting for resources Ex – food Ex – Limited # of Elmo dolls at target at an 8 am sale and 400 mommies waiting outside! Indirect = indirect fighting for resources Ex- nocturnal vs. diurnal Ex – mommy arrives at a 24 hour Target and buys the last doll before another mommy arrives at 8 am!

13. Two types of population Regulation: =The cause of death to regulate the population size can be: 1. Density Dependant 2. Density Independent

14. S – Curve Growth  Mimics a “S”  Population starts slow, then increases quickly, then begins to level off to support the current population at it’s maximum capacity.

15. Density Dependant = Death occurs more quickly in a crowded population than a sparse one.

16. Density Independent = death that is caused regardless of the pop.’s density. It affects all members of a population in a general/similar way.

17. 8.2 How species interact with each other (pg. 217) Niche = role in the ecosystem. Ex – physical home, env factors for its survival, and its interactions with others. Habitat = location. Ex -Where an organism lives

18. Species Interactions page 218 = based on whether each species causes benefit or harm to the other species in a given relationship. 1. Competition 2. Predation 3. Parasitism 4. Mutualism 5. Commensalism

19. Competition Defined as both species being harmed. May be in competition for mates, territory, food, etc.

20. Predation = defined as: benefits one and harming the other the other

21. Mutualism = defined as: Benefits both!

22. Parasitism = defined as: benefits one, harms the other

23. Commensalism = defined as one benefits and the other is unaffected. other is unaffected.

24. Symbiosis and Coevolution  Symbiosis is the relationship in which 2 species interact.  Typically in which one benefits.  Coevolution may occur b/w species in close relationship. - Without one, the other will die! - Without one, the other will die!