Monday, December 6, 2010

Genetics and Evolution

Definitions:
Genotype: Combination of alleles inherited by the individual.
Phenotype: Observable properties of the organism, as a result of their gene make-up.
Selective breeding: Intentional breeding of organisms with a certain desirable trait, in hopes of producing offspring with the same, or similar desired qualities.
Artificial selection:  Human intervention in the breeding of plants and animals, in order to ensure the succession of certain desirable traits.
Natural selection: According to Darwin, natural selection is the process by which the organisms who are best adapted to the environment are most likely to survive, and eventually pass along their genes to future generations. 
Ultimate explanation: Explanation of a trait at an evolutionary level. Describes the role that a specific behavior plays in promoting survival.
Proximate explanation: Explanation of a trait or behavior in terms of mechanism, describing the immediate causes and conditions for the behavior.
Biological preparedness: An innate ability to learn certain species-typical behaviors relatively easily. Ex Humans are born with specific anatomical structures to eventually allow the individual to talk.
Homology: A similiarity between species that can be traced and detected due to a common ancestor.
Analogy: A similarity between species that does not stem from common ancestry, but from convergent evolution.
Naturalistic fallacy: A perspective referring to the term good, as a natural property. 
Deterministic fallacy: A perspective, which claims that genes directly influence behavior, as opposed to considering the intricate interplay between genes and behavior.
Learning Objectives:

Explain why behavior is more than simply genes + the environment. (We think it's asking why behavior is a combination of genes and the environment. Correct us if we're wrong!)


Behavior is more than genes because there is a constant interaction with the environment, and more than the environment because genes create predispositions to certain behaviors directly, or indirectly to change the way one interacts with the environment and subsequently affect behavior.




Identify examples of phenotype and genotype.


Let’s say you wanted to determine the phenotype and genotype for eye color.
The phenotype, would be the color observed, such as brown or blue.
The genotype would be the allele combination responsible for producing this color.



Discuss phenotypes in relation to homology and analogy.


Phenotypes, being the observable trait due to the presence of certain genes, can be related to homology and analogy by the existence or non-existence of a common ancestor. Although two species may have a similar phenotype, they may or may not be deriving from a common ancestor.
Ex Owls, bats, and butterflies all have wings, but did not diverge from a common ancestor.



Interpret behavior as a dynamic interaction between genes and the environment:


Neither genes nor environment determine behavior directly on their own. The interplay between these two elements, where we live and function, and our biological mechanisms, create behavior by constantly influencing each other.



Identify different scientific approaches that may be taken to understand genetic components of alcoholism


Scientists could survey people with alcoholism in a family line and study their genetic components, or even start with non-alcoholics and watch the introduction of alcoholism into a family (as long as it is consented) and study the changes in genetic components of the subjects willing to be tested.



Identify brain regions and levels of electrical activity important for understanding effects of alcohol and alcoholism


Studying the P300 neural activity in alcoholics, and even just users of alcohol, studies show a decrease in P300 signal strength on an EEG (electroencephalogram). The P300 neural activity is responsible for the recognition of novelty in any given circumstance.



Evaluate different examples of potential evolution.


Remember that potential evolution is caused by several mechanisms, such as natural selection, mutations, selective breeding, and genetic drift (through the bottleneck effect (large number of the population dies off, leaving a certain genotype behind) or the founder effect (a small sample of the population is separated from the larger whole with a certain genotype frequency different than that of the original population).




Describe how evolution and functionalism are related.
Functionalism describes an approach by which psychologists try to explain behaviors by stating what it accomplishes. Evolution, then, allows psychologists to interpret changes in species behaviors, and possibly better understand the reasons for these change, and the presence of the current behavior.



Identify proximate and ultimate explanations for behavior.


A proximate explanation will describe behavior in terms of its mechanisms. For example, the ways in which songbirds are influenced to sing, and the processes involved in triggering this behavior.
An ultimate explanation will state the roles a certain behavior plays in the organism’s survival, and reproduction.




Apply the concepts of naturalistic and deterministic fallacies to describe erroneous beliefs.



Naturalistic fallacies are to be interpreted as incorrect because by considering behaviors with this concept, one interprets natural behaviors as being right, and therefore considered moral. Nature is neither moral or immoral, it is humans who determine this classification.
Deterministic fallacies are incorrect because they concur that behavior is a direct result of genes, implying that specific tendencies are passed directly through DNA. However, this is not true. Behavior arises from a mixture between the environment, and genes.
Thought Question:


How is evolution important for psychology? Describe how understanding evolution provides an important basis for taking a functional approach to understanding psychology.


By understanding evolution, psychologists are able to determine certain events or evolved characteristics and their progression over time. These changes provide insight to what has changed, and allows us to begin to explore possible causes of these changes. This is especially important when it comes to analyzing behaviors, because by understanding why organisms act the way they do, we can more easily hypothesize as to why these behaviors or traits have been retained or lost over successive generations.

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