1. Scientists found that, over a period of 200 years, a mountain pond was transformed into a meadow. During that time, several communities of organisms were replaced by different communities. Which of these best explains why new communities were able to replace older communities? a. The original species became extinct. b. Species in the older community died from old age. c. The abiotic characteristics of the habitat changed. d. Diseases that killed the older organisms disappeared.

2. In order to maintain the biodiversity in an aquatic ecosystem the water must have plenty of dissolved oxygen. Which of the following would increase the amount of dissolved oxygen available? a. Use heaters to warm the water because warm water has more available oxygen than cool water. b. Remove obstructions within the water way so that the water can maintain a steady flow because flowing water has more oxygen than stagnant water. c. Remove trees along the water way that rob the water of oxygen. d. Increase the amount of fertilizer run off leading to eutrophication.

3. How does succession impact the biodiversity in an area. A
How does succession impact the biodiversity in an area? A. Both primary and secondary succession increases the biodiversity after an environmental disturbance. B. Primary succession only, increase biodiversity since this occurs on brand new land while secondary succession maintains the biodiversity. C. Secondary succession only, increase biodiversity since this occurs on brand new land while primary succession maintains the biodiversity. D. Both primary and secondary succession decreases the biodiversity of an area because the disturbance wipes out life in the area.

4. Determining Population Size
There are four basic Methods that ecologists use to determine population size?
Direct observation
Indirect observation
Sampling
Mark and recapture studies

5. Determining Population Size
Determining the size of ant population by knowing the number of ants that inhabit one ant hill, and then observing how many ant hills are in one particular area.
Indirect observation

6. Determining Population Size
Ecologists estimate the size of the rainbow trout population in a lake by catching a small sample, tagging them and then releasing them. They come back three weeks later and catch another sample noting how many trout have tags, and how many do not.
Mark and recapture studies

7. Determining Population Size
Determining the number of frogs in a pond by counting all of them individually.
Direct Observation

8. Determining Population Size
Estimating the number of daisies in a 100 square meter meadow by counting the daisies in a 10 meter by 10 meter plot, and then multiplying by 100.
Sampling

9. Putting it all together
Direct observation of a population gives you the most accurate count of a population while indirect observation is more of an estimate. Why would an ecologist use indirect observation instead of direct observation.
Because it is not always practical to count all the individuals in a population.

10. Changes in Population Size
List 2 ways a population can change in size:
_______________________________
_________________________________
When new members join the population
When members leave the population

11. Changes in Population Size
Birth Rate
Number of births in a population over time.
Death Rate
Number of deaths in a population over time.
Immigration
New members move into a population.
Emigration
Members leave the population.

12. Changes in Population Size
Which Two allow a population to increase?
Birth Rate
Immigration
Which two allow a population to decrease?
Death Rate
Emigration

13. Changes in Population Size
What does the population statement say?
If birth rate > death rate, population size increases.
If death rate > birth rate, population size decreases.

14. Population Density The number of individuals in a specific area.
Unit Area

15. Limiting Factors
An environmental factor that causes a population to decrease.
Food and Water
Space
Weather

16. Limiting Factors
Pick one of the limiting factors and describe how it limits population growth.
Food and Water
Space
Weather

17. Carrying Capacity The largest population that an area can support.
Determined by the limiting factors that are present.

18. Carrying Capacity

19. Types of population growth

20. Predator-Prey Relationships
Without predators, certain species of prey would drive other species to extinction through competition.
Without prey, there would be no predators

21. Predator-Prey Relationships

22. Competition
When the population increases to a size so that resources such as food or space become limited, individuals in the ecosystem must compete for resources

23. R strategist vs K strategist
Unstable environment, density independent
Stable environment, density dependent interactions
small size of organism
large size of organism
energy used to make each individual is low
energy used to make each individual is high
many offspring are produced
few offspring are produced
early maturity
late maturity, often after a prolonged period of parental care
short life expectancy
long life expectancy
each individual reproduces only once
individuals can reproduce more than once in their lifetime
Mouse, frog
Whale, elephant