Explore BrainMass


Evolution is the process responsible for the genotypic and phenotypic changes which are seen in populations over subsequent generations. These changes are a result of variation in inherited characteristics.

Diversity can occur at all levels in a biological organism, from the basic DNA level to the species level. It is this diversity which has changed and become more complex over time. When life on Earth first arose, it was composed of very primitive life forms and the complexity and biodiversity which exists today has expanded greatly due to evolution.

The theory of evolution is based on natural selection, a principle that was discussed by Charles Darwin almost 150 years ago. This process of natural selection requires there to be phenotypic variation within populations. In natural populations variation arises often, due to processes such as mutations and this variation which is represented by traits gets inherited over subsequent generations. Evolution is also dependent on traits being heritable. The success of individuals in terms of reproduction and survival vary because of the specific traits they possess.

Evolution has influenced every aspect of organisms; their behaviour, morphology and physiology. Stressful conditions or environmental changes will force organisms to find ways to adapt to altering conditions. The process of adaptation is influenced by evolution because through natural selection the most beneficial traits for survival will be selected for and deleterious traits will slowly get removed as individuals possessing those traits will not be able to survive.  

Evolution is not a theory about the origin of life, but a theory about how life diversified after its origin. Furthermore, evolution is not a ladder of progress, rather it is a process in which fitness is linked to the environment and organisms are created to be able to reproduce and survive. Evolution by natural selection is not a process dependent on chance because those traits which are most common today are those which originated from the predecessors who were best able to ensure their reproduction and survival.

Categories within Evolution

Another Take on the Creationism/Evolution Debate

Should creationism and evolution be left out of curriculum at the public school level. Even though we have had issues in the past when linking them to religious beliefs should we still discuss the topic and remain open minded or keep it out of our studies completely?

Invertebrate Diversity, Evolutionary History, and Origins

Question 1 In which we explore hominin diversity. A. Explain the evidence that suggests hominins did not evolve in a straight line leading directly to our species. Question 2 In which we explore invertebrate diversity. A. Explain how a hydrostatic skeleton helps an animal keep its shape and move. Questi

Evolution of Antibiotic or Pesticide Resistance

For many years, antibiotics have been effectively used to treat bacterial disease; and pesticides have been used to protect our agricultural crops from many kinds of pests, including insects, worms (nematodes), fungi, or agricultural weeds, for example. A growing concern for treating bacterial diseases or pest outbreaks is

Theory of natural selection is explicated.

Examine the mechanisms of evolution. Describe how natural selection results in biodiversity. Explain why biodiversity is important to continued evolution. Examine mutations and sexual recombination, which are sources of genetic variation.

Fish study

"You have been asked to study two recently discovered fish species, both found in waters off a small island. The two species are very similar in general structure, but there are two key differences between them. In species A, males are brightly patterned with blue, red, and purple scales, whereas the females are drab, and males

Evaluation: Contributions

Outline the major contributions of scientists to concepts in evolution. Describe the contributions of Lyell, Malthus, Lamarck, Darwin, and Gould and Eldridge. Please write one paragraph or a few sentences on each of the above mentioned people.

Causes of Mass Extinction

What evidence do we have for the cause of the mass extinction at the end of the Cretaceous? What were two results of this extinction event?

Discussing the Theory of Evolution and Natural Selection

According to the Theory of Evolution, Natural Selection is the mechanism by which evolution occurs. The process of natural selection is based on the following four postulates: Postulate 1 - Individual members of a population differ from one another in many respects. Postulate 2 - At least some of the differences among member

Discussion on Various Aspects of Evolution

1. Populations are distinguished from other populations by their: a. collective phenotypes. b. collective genotypes c. gene frequencies d. gene pools e. all of the above 2. The Hardy-Weinberg formula allows geneticists to determine a population's gene frequencies from direct observation of its ___________.

Genetic Biology

1. Propose an explanation as to why there is a relatively high incidence of dwarfism among the Old Order Amish of Lancaster, Pennsylvania. 2. What is the minimum criterion used to determine if two similar individuals are members of the same species? 3. Why are marsupials found almost exclusively in Australia? 4. How did Da


1. What role did Darwin's voyage on the Beagle play in the development of his theory of evolution? 2. Explain influence of Malthus' theory on Darwin's thinking. 3. Why do the sizes of populations tend to remain fairly stable despite the large numbers of offspring which can be produced?

Species diversity: develop a hypothesis about beak size in finches

A group of researchers spent 8 years in the Galapagos Islands measuring beaks, observing feeding behavior, and measuring rainfall in a population of a particular species of Darwin's finch. They found that this species eats only small seeds and that its beak enables the bird to crack and eat such seeds quickly and efficiently. Th

Polymorphism in bird populations

You are investigating the Bmp4 gene, which is involved in beak development, in the Darwin's finch Geospiza fortis. You find a DNA polymorphism, a single-base difference between two alleles at this locus. a) Does this polymorphism necessarily have an effect on the phenotypes of the birds of this species? Justify your answer.

2 Questions on Life Science

Natural selection is the key mechanism of evolution and accounts for the commonality and diversity in nature. Can you give a specific example of a successful species and unsuccessful species adapting and not adapting respectively to their environments and why their adaptations or lack of made it so? How can having high level

Life on earth (biological concepts from the non-science major perspective)

1. Cite one piece of evidence supporting the theory of evolution. Why does it support evolution? 2. Describe one contributing factor to mass extinction. 3. Describe 2 of the following 3 terms and give an example of each (include the example and the organism to which it belongs): homologous structures, analogous structu


I need help with question # 2, 5, and 6. For number 5, I need an explaination for the reason for each number and for number 6 I would prefer a chart. 2. The definition of a species varies among different schools of thought, discuss (compare and contrast), two concepts. 5. Using the information you hgave gained, arrange the