These explorations are intended to expand your understanding of the processes that are responsible for evolution. Use your favorite Internet search programs to roam around the World Wide Web and discover what other people who have interest in these subjects have said to explain and support their views. Seek out reliable, factual sources. Do not stop at just two or three. It is worth the extra time to thoroughly research these questions and get views on all sides of the issues.
Questions to Explore
1. The founder principle is an explanation of the high frequencies of O type blood among American Indians and of Huntington's disease among people living around Lake Maricaibo in Venezuela. Search the Internet for more examples of the founder principle and describe them. (HINT: most of our knowledge of this phenomenon relates to the inheritance of unusual diseases at high frequencies in small populations. There is a good example of this phenomenon in the French speaking areas of Canada.)
2. Continuous positive assortative mating usually results in high frequencies of recessive alleles being expressed in the phenotype of individuals. When these homozygous recessive inheritance patterns are the cause of serious medical conditions, it can be a problem for the future of a population. This fact is well known by zoo keepers and professional animal breeders. Search the Internet for examples of such problems in particular species of animals that are frequently inbred. Describe these examples. (HINT: this is a common problem among many of our purebred domestic animals.)
3. Search the Internet for a natural selection related explanation of the genetically inherited high frequency of hypertension (high blood pressure) found among African Americans. Describe the evidence. What other explanations are there for this high rate of hypertension? (HINT: the ancestral African American populations in West Africa do not have high frequencies of hypertension. Therefore, it is likely that something happened to African Americans following their initial enslavement in Africa.)
4. Search the Internet for examples of punctuated equilibrium showing up in the fossil record. Describe these examples. What environmental changes explain each of them? (HINT: Stephen J. Gould was a leader in the documentation of this evolutionary pattern.)
Help Getting Started
If you have not been satisfied with the search programs that you have used in the past, try one of the following. Each has its strengths and weaknesses. Unfortunately, none of them can link you to everything available on the Web today because of the rapid growth of sites and the way search engines selectively exclude certain kinds of sites.
Old Standby General
If you don't have success searching with these programs, take a look at the Related Internet Links section of this tutorial.
CAUTION: In doing your searches, keep in mind that not everything on the Web is accurate, current, or true. To help discover which sites can be trusted and which ones cannot, ask yourself the following questions:
1. Who are the authors of the site? What are their credentials? Are they experts? 2. Is the information current? When was the website created and last updated? 3. Do the facts presented in the site seem correct? 4. Is the purpose of the site to objectively inform and explain or to persuade and sell a particular perspective?
Copyright © 2000-2012 by Dennis O'Neil. All rights reserved.