Biochemistry Grade 12 Isu

Population Dynamics:

Independent Study Unit

Ebony Jack

Mrs. Sanelli

SBI 4U1

10/12/15

SB14U POPULATION DYNAMICS – PART 1

1a) In order to study populations, scientists need to be able to describe a population. Scientists use population density, population size and population dispersion.

b) Population size: the number of individuals of a specific species occupying a given area/ volume at a given time.

Population density: the number of individuals of the same species that occur per unit area or volume.

Population size and population density differ from one another because scientists measure such characteristics as population size and the estimated total number of organisms, and the density and dispersion of organisms within their habitat.

c) D = N/S

    D = 200 wolves/ 1000 ha

    D = 0.2 wolves/ ha

d) Population density can be deceiving because of unused or unusable space within a habitat. Ecologist, therefore, distinguish between crude density and ecological density.

2a) Crude density: population density measured in term of number of organisms of the same species within the total area of the entire habitat.

Ecological density: population density measured in terms of the number of individuals of the same species per unit area or volume actually used by the individuals.

b) Crude density is the number of individuals of the same species per total unit area or volume, and ecological density is the number of individuals of the same species per unit area or volume actually used by the individuals. Population density can be deceiving because of unused or unusable space within a habitat. Ecological density measure a higher density.

3. Population dispersion is the general pattern in which individuals are distributed through a specified area.

4a) Clumped dispersion is the pattern in which individuals in a population are more concentrated in certain parts of a habitat. Examples of this are cattails. They are restricted to growing along the edges of ponds or lakes.

b) Uniform dispersion is the pattern in which individuals are equally spaced throughout a habitat. An example of this are when king penguins nest on South Georgia Island in the South Atlantic Ocean; they often exhibit a nearly uniform dispersion pattern.

c) Random dispersion is the pattern in which individuals are spread throughout a habitat in an unpredictable and pattern less manner. An example of this are some species of trees in tropical rain forests, they exhibit random dispersion (although this pattern is rare in nature).

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d) The type of relationships within a habitat ultimately determines what type of dispersion pattern a species will exhibit.

e) Random dispersion pattern is the rarest in nature. I think this is because abiotic factors usually cause organisms to be clustered or spread apart. Random dispersion usually occurs in habitats where environmental conditions and resources are consistent. Dandelion seeds are an example. They are randomly dispersed when the wind blows.

SBI4U POPULATION DYNAMICS – PART 2

1a) The term environment is the surrounding or conditions in which a person, animal, or plant lives operate.

b) Some biotic resources that may be limited in an ecosystem at any one time is the availability of food.

c) Some abiotic resources that may be limited in an ecosystem at any one time is access to water.

2a) The carrying capacity of a biological species is an environment is the maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water and other necessities available in the environment.

b) The carrying capacity for species and populations of the same species differ. Ex. Two populations of the same species of fish might occupy quite different ecosystems with different carrying capacities, due to biotic and abiotic variations in the environment.

c) The carrying capacity of an environment may vary for different species and may change over time due to a variety of factors, including: food availability, water supply, environmental conditions and living space.

d) Population size may increase when individuals immigrate and decrease when individuals emigrate.