ecology of populations (1) limiting factors that affect populations in an ecosystem hickox: baker...

Ecology of Populations(1) Limiting factors that affect populations in

an ecosystem

Hickox: Baker High School Biology

Ecology of Populations

(2)__________- Study of the interactions of organisms with other organisms and the physical environment

(3)__________ - Place where an organism lives.

(4) _______________ All the organisms within an area belonging to the same species.

(5) ______________ All various populations interacting at same locale.

(6) ______________Community of populations including biotic and abiotic factors.


Ecology

Habitat

Population

Community

Ecosystem

Ecological Levels

Hickox: Baker High School Biology 3

Standard 16


Density-Dependent Factors

Includes(7) Parasites

and(8) Predators

Factors that affect population growth

and depend on (9)_________

Human (10)____________ such as tuberculosis often become epidemics in crowded cities.

Locust plagues


5

density

disease

Density-Independent Factors

Weather EventsTemperature

6

forest fires

hurricanes floods

Regulation of Population Size• Density - Dependent Factors

– Number of organisms present (13)influences the effect of the factor.

(14) Competition(15) Predation (predators) (16) Disease

• Density - Independent Factors– Number of organisms present does (17) not

influence the effect of the factor.(18) Natural Disasters


Question 1:Which situation is caused by a density-independent limiting factor?A. The influenza outbreak of 1918-1919 killed over 20 million people.

(number of organisms was influenced by factor)B. The cones of the jack pine need heat from a fire to help release seeds.

(number of organisms was not influenced by factor)C. A parasite alters reproduction in a woodpecker population causing fewer

births.(number of organisms was influenced by factor)D. A queen bee regulates the number of eggs she lays according to the

amount of food available. . (number of organisms was influenced by factor)

Hickox: Baker High School Biology8

Density - Independent Factors• Number of organisms present does not influence

the effect of the factor.• Natural Disasters and Temperature

B.

Question 2Which limiting factor is density-Independent for rainbow trout?A. Size of the stream (number of organisms was not influenced by

factor)B. Spread of parasites (number of organisms was influenced by

factor)C. Competition for food (number of organisms was influenced by

factor)D. Supply of dissolved oxygen (number of organisms was influenced

by factor)


Density - Independent Factors• Number of organisms present does not influence

the effect of the factor.• Natural Disasters and Temperature A.

Question 3:Which statement BEST describes the relationship between natural disasters

or human-caused disasters and population size?A. Natural and human-causing disasters are density-dependent factors.

(Not Natural Disaster)B. Natural and human-causing disasters are density-independent factors.

(Natural Disasters are density-independent)C. Human-causing disasters are density-independent whereas natural

disasters are density-dependent. (Not Natural Disaster)D. Human-causing disasters are density-dependent whereas natural

disasters are density-independent. (Not Natural Disaster)


Density - Independent Factors• Number of organisms present does not influence the effect of the

factor.• Natural Disasters B.

• Density - Dependent Factors– Number of organisms present influences the effect of the factor.

• Competition• Predation• Disease Hickox: Baker High School Biology 11

Question 4:Which relationship BEST identifies a density-dependent limiting factor?A. A bobcat population declines due to disease. (number of organisms

influence the effect of the factor; competition, predation, disease)

B. A fish population declines due to a severe drought.(not competition or predation but natural disaster)

C. A bird population declines due to pollution. (not competition or predation but disaster)

D. A wolf population declines due to a cold winter. (Number of organisms present does not influence the effect of the factor.- Independent)

A.


• Competition and Predation and Disease Hickox: Baker High School Biology12

Question 5:Study the table below. Caterpillars can destroy trees by eating too many leaves and making them susceptible to disease or drought. Which student has correctly identified the density-dependent and density-independent limiting factors associated with an invasion of Gypsy Moth Caterpillars?

4.

Student Populations of Caterpillars Disease Drought1 Density-independent Density-dependent Density-dependent

2 Density-dependent Density-independent Density-independent

3 Density-independent Density-independent Density-independent

4 Density-dependent Density-dependent Density-independent

Density - Independent Factors• Number of organisms present does not influence the effect of the factor.

• Natural Disasters

Question 6:Study the table below. Which student identified only density-independent limiting factors?

Student’s Identification of Density-Independent Limiting Factors





Competition and Predation and Disease

Student Disease Clear-cutting Predation Filling Wetlands

Natural Disaster

1 X X X

2 X X X

3 X X X

4 X X X

4.

Question 7: Which statement BEST explains why a disease my affect one population more than another population?

A. Because disease is a density-dependent limiting factor, a larger population makes it easier for the virus to spread from person to person

B. Because disease is a density-independent limiting factor, a large population makes it easier for the virus to spread from person to person

C. Because disease is a density-dependent limiting factor, climate can influence the disease, making it more or less affective.

D. Because disease is a density-independent limiting factor, climate can influence the disease, making it more or less affective.


14




Competition and Predation and Disease

A.

Uniform Distribution


Random Distribution


Clumped Distribution


ecology of populations (1) limiting factors that affect populations in an ecosystem hickox: baker...

Documents

densityindependent factors

factor hickox

natural disasters hickox

food number of organisms

parasites number of

stream number of organisms

densitydependent factors

densityindependent c