LIMITING FACTORS REVIEW SHEET

Limiting Factors: factors in the environment that can effect the size of a population.( Ex. Rain in the desert)

DENSITY INDEPENDENT FACTORS

Density independent factors can affect a population no matter what it’s density is…

Natural disasters: droughts, floods, hurricanes and fires.

Temperature: Some organisms cannot survive high temperatures, some cannot survive low temperatures.

Sunlight: plants will die with sunlight for photosynthesis.

Human activities: hydroelectric dams, pollution, deforestation.

Physical characteristics: camouflage, bright colors

Behaviours of organisms: migration, mating dances, singing,

DENSITY DEPENDENT FACTORS

Density dependent factors can only affect a population when it reaches a certain density…

Competition: organisms in the same habitat must compete for food, water, space, and shelter.

Predation: Too many predators = too few prey. Too few predators = too many prey..

Disease: Higher populations make it easier for parasites to find hosts and spread the disease.

Parasitism: more hosts = more food for parasites

Crowding: too many organisms, not enough food, water, or shelter.

Classify each of the statements as Density Dependent or Density Independent

1.Rainbow smelt and yellow perch attempt to occupy the same area. The more aggressive smelt survive; the perch do not.

2.A severe flood brings a lot of sediment into Lake Winnipeg. The muddiness of the lake increases greatly.

3.A drought decreases the water level in Lake Winnipeg. The carrying capacity of the lake decreases.

4.Due to the introduction of rainbow smelt, Lake Winnipeg becomes crowded.

5.Northern pike prey on yellow perch, an increase in the perch population causes an increase in the pike population.

6. Many fish die due to an increase in water temperature.

7. Due to over-fishing, the number of walleye in Lake Winnipeg decreases.

8. A population is growing quickly when parasites cause disease to spread quickly.

9. Since lake sturgeon migrate long distances to spawn, many do not survive the trip.

10. A hurricane hits the coast and the waves destroy many oyster beds.