Evolution and Natural Selection - Ch. 13 Flashcards
What’s the difference between hypothesis, law, theory, and dogma?
Hypothesis: educated guess to explain a problem (GUESS)
Law: set of observed regularities expressed in a concise verbal or mathematical statement (DESCRIBE)
Theory: explanation for an observation that is backed up by a considerable amount of evidence (EXPLAIN)
Dogma: not tested; belief system
Can a theory ever become a law?
No. Theories have even more data and explanations than laws do.
What is artificial selection?
selected breeding in domesticated species to achieve desired traits
What are 2 conditions for natural selection?
Individual Variation and Overproduction
What is “fitness”?
fitness = survival and reproduction; an organism’s contribution of genetic information to future generations
What is homology?
similarity in structure due to common ancestry
What is embryology?
The more closely related 2 species are, the more similar their embryo will be for a longer period of development.
What was Darwin’s boldest hypothesis?
All forms of life are related to some extent through branching evolution form the earliest organisms.
What is the definition of evolution?
change of allele frequencies over time
What are the 2 types of natural selection (besides artificial)?
Environmental Selection- external pressures from environment driving selection, e.g. food, disease
Sexual Selection- mating preferences drive selection
What is the ultimate result of natural selection?
Evolutionary adaptation. Adaptations are traits that have been subjected to natural selection.
What are 3 outcomes of natural selection?
- Directional Selection- shifts overall makeup of population by favoring ONE extreme
- Disruptive Selection- favors opposite extremes over intermediate/middle
- Stabilizing Selection- removes the extremes from the population; intermediate are most successful
What’s sexual dimorphism?
The phenotypic difference between males and females of the same species (for example, male peacocks are brightly colored, females are brown and plain)
What is genetic drift and what are the 2 types of genetic drift?
Genetic drift is the change in the gene pool of a small population due to CHANCE.
Bottleneck Effect- large population is drastically reduced by disaster. Some alleles are lost due to chance. Much less genetic diversity.
Founder Effect- establishment of a new colony whose gene pool differs from the parent population.
What are vestigial structures?
Remnants of features that served as important functions in the organism’s ancestors, e.g. wisdom teeth, hip bones in snakes, appendix. They are NEUTRAL; not harmful.
