Biochemistry Grade 12 Isu

Independent Study Unit:

Population Dynamics

Ebony Jack

SBI4U

Ms. Sanelli

January 4th, 2016

Part I

Characteristics of Populations

1a) Three different measurements that scientists use to describe populations are population size, the density of the population by area, and the dispersion of the organisms within the area being studied.

b) Population size is the number of individuals of a specific species occupying a given area/volume at a given time. Population density is the number of individuals of the same species that occur in a specific area or volume. Population size is a measurement of the total number of individuals in a population, while density measures how spread out the population is.

c) Number of individuals: 200 wolves

Space occupied by population: 1000 ha

The size of this population is 200 wolves.
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        The density of this population is 0.2 wolves/ha.

d) Two reasons why I might expect this to be true are firstly that with smaller organisms, more of them are able to fit into a given area/volume than larger organisms (e.g. you can fit more ants into a square kilometre than you could cows). Secondly, smaller organisms tend to live in larger groups/colonies keeping a large number of them closer together and therefore more dense where as larger organisms usually live in smaller groups/packs, making them more spread out.

2.        a)        What is the difference between "crude density" and "ecological density"?  

Crude density is the measurement of the population density in terms of the number of organisms of the same species within the total area of the entire habitat. Ecological density is the measurement of the population density in terms of number of the number of individuals of the same species per unit area or volume actually used by the individuals. Crude density includes the size of the organism's entire habitat whether or not the organism is able to use all of that space, where as ecological density only includes the space that the organism is able to use in the calculation.

        b)        Why is this distinction (i.e., crude versus ecological density) necessary?  Which of these two measures of density is typically higher?  

This distinction is necessary because including space that is unusable to the organism in your density calculation can be misleading as the organism is not actually able to occupy some of the space. The ecological density is typically higher because, while eliminating the space that the organisms do not occupy, you will see that the organisms are in fact closer together and therefore have a higher density.

3.         What is meant by the term "population dispersion"?  

        Population dispersion is referring to the general pattern in which individuals are distributed through a specific area.

4.         a)        Describe what is meant by a "clumped dispersion pattern".  Include a diagram with your description.  Provide an example of this type of dispersion pattern from nature.  

        A clumped dispersion pattern means that individuals in the population are more concentrated in certain areas of the habitat. An example of this dispersion pattern in nature would be schools of fish as they travel in large groups.

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        b)        Describe what is meant by a "uniform dispersion pattern". Include a diagram with your description.  Provide an example of this type of dispersion pattern from nature.

        A uniform dispersion pattern means that individuals in a population are equally distanced and spaced out throughout the habitat. An example of this dispersion pattern in nature would be penguins as they tend to create their own personal space, keeping a roughly equal distance from each other.

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        c)        Describe what is meant by a "random dispersion pattern". Include a diagram with your description.  Provide an example of this type of dispersion pattern from nature.

        A random dispersion pattern means that individuals in a population are spread throughout the habitat in an unpredictable manner, without any pattern. An example of this dispersion pattern in nature would be plants such as dandelions as the seeds are carried by the wind and planted sporadically.