Activity: genetic and ecosystem biodiversity

Hint: the background information that will help you complete this activity is found in the videos and article.

In this activity you will observe physical variation in several individuals from one species. Making careful observations is an important scientific skill.

Background information: Variation fuels the process of evolution. No two individuals of any species are exactly alike. Even if they look similar, differences in their genes distinguish one from the other. While subtle, those differences may allow some to live longer and produce more offspring than others. That process – called natural selection – drives evolution.

Individual variation is a fundamental prerequisite for evolution to occur. The ultimate source of the variation is mutations or changes in the DNA and chromosomes of individuals that then get passed on to offspring. In all organisms that reproduce sexually, an individual receives genetic information from each parent. The different versions of a single gene (such as blue or brown for the human eye color gene) are called alleles, and individuals have two alleles for each gene, one inherited from the mother and the other from the father. The alleles, the different versions of genes, determine the organism’s traits. Individual variation occurs because each individual has a different combination of alleles. We can see some of this genetic diversity expressed physically in what is called the phenotype of the organism, all the observable features. Even closely related individuals like brothers and sisters show phenotypic variation. The appearance of individuals can also be influenced by the environment.

Activity procedure:

a)    Find five to ten individuals of the same species. You can look at flowering plants in your yard, trees in a park, insects in a garden or museum, or a litter of puppies or kittens. The choice is yours! You just need to make sure they are all members of the same species.

b)   Look closely at each individual of your chosen species. What variation can you observe among the individuals? You can measure body parts if you want. Try sketching each individual to record the variation. Be sure to include labels, measurements, and description notes to enhance your sketch and make it more informative. You can also take photographs to document the variation.

c)     After you are done with your observations, answer the following questions:

i.         What types of variation did you observe in the individuals (e.g., color, size, shape, number of spots, numbers of individual parts such as petals)?

ii.         Where do you think the variation you observed comes from?

iii.         Why is variation among individuals important in populations?

iv.         Do you think an individual has other variation that you cannot see?