Evolution Study Guide Exam 1
This study guide will go over the terminology and topics talked about in lecture and that would appear in the online readings.
Evolution is thought to be the process of how organisms diversified and developed since life started on Earth.
Evolution is happening now for instance, the flu, viruses, malaria, and bacterial infections. They all evolve due to pressures brought on by their environments. Whether is be caused by humans creating medicines and vaccines to kill the diseases or natural causes.
● Natural Selection
There are three main ways to tell if natural selection is occurring
1. Variation within the population
2. Differences in fitness
3. Alleles are heritable from parent to offspring
Natural Selection has a larger impact on large populations rather than small ones
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Natural Selection is not evolution, it is a factor that causes
There are three types selection:
Stabilizing Selection Favors individuals whose trait values are near
the population mean. A graph is provided to the left.
Disruptive Selection The smallest and largest individuals have
higher fitness than individuals near the mean. A graph is provided to
Directional Selection Favors either an increase or a decrease in a traits mean. A graph is provided to the left.
Adaptation A characteristic of an organism that evolved by natural selection that makes it more fit for its environment.
Mutation They are a great source for creating genetic variation. Deleterious mutations negatively affect the individual organism, lowering its fitness. While, advantageous mutations are beneficial for the organism raising its fitness. Lastly, there are neutral mutations which neither hurt or benefit the organism
Nonsynonymous mutation Changes an amino acid and alters the protein in a way that decreases the survival or reproduction of an organism
● Sexual Selection
Sexual selection goes hand in hand with natural selection because reproductive success is how genes are passed on through generations If you want to learn more check out banded barrel vault
Intersexual Selection When a female chooses a mate based off certain traits that indicate healthy genes
Intrasexual Selection “Typically amongst males” competitively fighting amongst themselves in order to mate with females
Primary Sexual Traits The gonads and genitalia that distinguish males and females
Secondary Sexual Traits Differ between sexes and are often among the most rapidly evolving phenotype characters. These traits are used by males to successfully mate with females
Sperm competition A way males interfere with each others reproduction. For example, some males have special adaptations that help remove the previous males sperm so their sperm will have a better chance of becoming offspring. Other males guard their female until she has her babies. While in some species the females have multiple partners so the males will have larger testes to produce copious amounts of sperm.
Direct Benefit Resources provided by the male that increase the female’s survival and reproductive success
● Genetic Drift
A process other than natural selection that causes evolution and occurs by the random fluctuations in the frequencies of genotypes within a population
It is not based on which organism is more fit for its environment. It can be caused by an individual running over several ladybugs of a population and randomly killing them or a natural disaster that randomly wipes out half a population and with it half of the genetic variation that was once available If you want to learn more check out clcv 102 uiuc
Genetic drift has a greater impact on small populations rather than larger populations
Bottleneck Effect A catastrophic event that kills majority of the population, so deviations among the survivors are statistically significant.
Gene Pool All the genes of a species within a population
Homology Are structural similarities in certain species as a result of a common ancestor
Gene Flow The mixing of alleles from different populations
Founder Effect When a few organisms become isolated from their original population, any deviation among the founders are statistically significant
Dispersal Describes the movement of an individual's gametes
Active dispersal: migration animals
Passive dispersal: pollen of plants getting blown in the wind
Heterozygosity The genetic differences of geographically different populations of the same species, usually caused by founder effect. The geographically closer a population is to its original population the more similar their genetics will be
HardyWeinberg Equation Is used to determine if evolution is occurring in a population p2+2 pq+q2=1❑ Requirements for HardyWeinberg random mating If you want to learn more check out gatech math
p= frequency of dominant allele large population size
q= frequency of recessive allele no mutations
● Phylogenetic Trees
These are essential tools for evolutionary biology because they help explain patterns of certain traits among groups/different species of organisms
They can also provide a timeline for when specific organisms were alive and show where two organisms had a common ancestor at some point in time
It is important to understand what the information in these trees are saying about the species dictated on the branches
Uniformitarianism The same physical processes that operated in the past, operate in the present. There are two versions of Uniformitarianism.
Determinist: Given starting conditions, every event in the universe is fully determined in advance by the laws of nature
Indeterminist: Events are not fully determined in advance, and chance plays a fundamental role in what happens If you want to learn more check out elisa mandell
We also discuss several other topics like • What are the choices concerning exchange rates?
Molecular Clock What is used to graph the average rate of mutations a species DNA accumulated, as well as measure developmental diversity in a species
A lot of what is talked about in this study guide goes hand in hand. The best way to remember this information is to make up scenarios in which these terms/definitions would work. Also, review the lecture slides, worksheets, and the CogBook’s quizzes because the exam questions will be set up in a similar format.