BIOL 202 Study Guide - Final Guide: Inbreeding Depression, Genotype Frequency, Watchmaker Analogy
Unit 1. Microevolution
1. Evolution defined – change in allelic frequencies.
a. Be familiar with at least six lines of evidence for evolution:
i. Homology - the state of having the same or similar relation, relative position, or structure.
Example, legs of a centipede.
ii. Vestigial traits - Structures like the human tail bone and whale pelvis are called vestigial
structures.
iii. Dead fossils found on region, resembled living organisms in the region.
iv. Transitional forms - Fossils or organisms that show the intermediate states between an
ancestral form and that of its descendants are referred to as transitional forms.
v. Species living on separate islands resembled each other.
vi. Biogeographic forms
2. Be familiar with some counter arguments against evolution and what the flaws of these arguments are (focus on
Paley’s watchmaker analogy). That there is higher being out there.
3. Mechanisms of evolution
a. What are the mechanisms of evolution?
i. Mutation - Mutation can be defined as a change in the DNA sequence within a gene or
chromosome of a living organism.
ii. Gene Flow (AKA Migration) - refers to the transfer of genes from the gene pool of one
population to another. Gene flow may change the frequency and/or the range of alleles in the
populations due to the migration of individuals or gametes that can reproduce in a different
population.
iii. Natural Selection - Natural Selection leads to an evolutionary change when some individuals with
certain traits in a population have a higher survival and reproductive rate than others and pass on
these inheritable genetic features to their offspring.
iv. Drift - consists of random fluctuations in the frequency of appearance of a gene, usually, in a
small population
b. Natural selection – four necessary and sufficient conditions:
i. Cells that replicate
ii. Hereditary information
iii. Variation in structure of cells
iv. Some cells with particular structures survive and reproduce better than others
= differential survival and reproduction
c. Relationship between population size and mechanism of evolution
i. Founder effect - founder effect is the loss of genetic variation that occurs when a new population
is established by a very small number of individuals from a larger population.
ii. Population bottleneck - a sharp reduction in the size of a population due to environmental events
(such as earthquakes, floods, fires, disease, or droughts) or human activities (such as genocide)
iii. Inbreeding and inbreeding depression - Inbreeding depression is the reduced biological fitness
in a given population as a result of inbreeding, or breeding of related individuals.
4. Hardy-Weinberg equilibrium
a. How do you calculate expected genotype frequencies when H-W eq. applies?
b. What are the conditions for H-W eq.?
Hardy and Weinberg's work told us that allele frequencies will not change significantly over the course of
generations as long as the following five conditions are met:
(1) The population is large
(2) There is no mutation
(3) No migration of individuals into or out of the population (no “gene flow”)
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(4) No one genotype has, on average, higher survival, and reproductive output than any other genotypes;
i.e., there is no natural selection
(5) Individuals mate at random with respect to genotype.
i.
5. Abiogenesis – origin of life.
a. Ancient origins of life (How do we know when life originated on Earth?) 4.5 BYA.
b. What are the models of abiogenesis? (SPONCH K)
i. Oparin-Haldane model – Reduction atmosphere (Miller-Urey conditions) makes biomolecules.
This atmosphere, exposed to energy in various forms, produced simple organic compounds
("monomers"). These compounds accumulated in a “pre-biotic soup". By further transformation,
more complex organic polymers— and ultimately life— developed in the soup.
ii. Autocatalytic closure – parts become whole. Reactions occur among a set of molecules. The
molecules catalyze the reactions that make other members of the set
iii. Genetic takeover – the original replicators were not biochemicals at all, but instead were
minerals.
iv. RNA World (Self-replicating molecules)
v. Panspermia – life was created on another planet and then was transferred here.
c. Which do you think is most plausible and why? Oparin-Haldane model because it contains the basic
organic compounds of life necessary for life.
6. Origins of evolutionary thought
a. Who contributed most to our current understanding of evolutionary processes?
Common ancestor
Erasmus Darwin
Catastrophism
Cuvier
Felt needs
Lamarck
Argument from design
Paley
Gradualism
Hutton
Uniformitarianism
Lyell
Populations grow at a faster rate than the rate
resources are produced
Malthus
Particulate inheritance
Mendel
Linked descent with modification and natural
selection
Charles Darwin
7. Adaptation: (nature) Differences: changes within a population, directly heritable through DNA, built in.
Similarities: adjustment to environment, increases survival and or reproductive success.
8. Acclimation: (nurture) Difference: changes within individual, not directly heritable, acquired.
9. Fitness (Darwinian): Measures the probability of survival and number of offspring.
10. Fitness (health): Can improve / deteriorate during lifetime, changes acquired during lifetime
11. Mendel’s laws of segregation - states that during the production of gametes the two copies of each hereditary
factor segregate so that offspring acquire one factor from each parent.
12. Independent assortment – formation of random combinations of chromosomes in meiosis and of genes on
different pairs of homologous chromosomes by the passage according to the laws of probability of one of each
diploid pair of homologous chromosomes into each gamete independently of each other pair
Unit II: Macroevolution
1. Macroevolution - major evolutionary change. The term applies mainly to the evolution of whole taxonomic
groups over long periods of time.
2. Microevolution - evolutionary change within a species or small group of organisms, especially over a short
period.
3. Evolutionary mechanisms continued
a. Sexual selection: natural selection arising through preference by one sex for certain characteristics in
individuals of the other sex.
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i. How does sexual selection take place? Occurs when females choose between male mates
ii. What are the evolutionary outcomes of sexual selection? Results in sexually dimorphic traits that
are exaggerated, or more elaborate, in the sex with highest reproductive variance
iii. Relate resource allocation to differences between males and females.
4. Natural selection - when populations of organisms are subjected to the environment. Those that adapt to the
environment and survive reproduce more and pass on their genes to the offspring.
5. What are the different modes and what are the expected consequences of each mode in terms of phenotypic
variation and mean phenotypic state? – exam 2 study guide.
6. Which mode of speciation is more common? Allopatric
7. Phylogenetics
a. Interpret phylogenies to determine relatedness among taxonomic units
b. Understand basic principles for inferring phylogenies
i. Parsimony
ii. Synapomorphy - a trait share by 2 or more taxa and their most recent common ancestor.
plesiomorphy - an ancestral character or trait state shared by two or more taxa.
iii. apomorphy - A characteristic believed to have evolved within a family tree; can be used to
separate one group from the other.
iv. What is evolutionary convergence, and how can it be detected? It occurs when two species from
unrelated lines develop the same traits or features. Convergent evolution is the
independent evolution of similar features in species of different lineages. Convergent evolution
creates analogous structures that have similar form or function but were not present in the last
common ancestor of those groups.
v. What is homoplasy? Homoplasy in biological systematics is when a trait has been gained or lost
independently in separate lineages during evolution
Unit III: Population Ecology
1. Highlight similarities and differences between ecology and evolution
a. Ecology (nurture) is the study of the relationships of organisms to their environment and to one another.
Nurture is learned behavior that can be changed based on experiences, for example hunting, fishing,
learning how to ride a bike etc.
b. Evolution (nature) is the change in allelic frequencies of an organism or the change that occurs in the
characteristics of living things through time. Nature is what we are made up of, our genetic material
which cannot be changed. We cannot change our height or eye color or any genetic material.
2. Populations: are a group of interbreeding individuals. Biology – a group of organisms of one species that
interbreed and live in the same place at the same time. Statistics – a set of individuals, objects, or data from which
a statistical sample can be drawn.
3. Models of population growth
a. Exponential / geometric: Biological exponential growth is the exponential growth of biological
organisms. When the resources availability is unlimited in the habitat, the population of an organism
living in the habitat grows in an exponential or geometric fashion. The graph for exponential growth
looks like a J.
What is the defining feature of exponential growth? The growth rate is constant.
b. Interpret logistic growth as a model of intraspecific competition. In logistic growth, a population's per
capita growth rate gets smaller and smaller as population size approaches a maximum imposed by limited
resources in the environment, known as the carrying capacity (K). Logistic growth produces an S-shaped
curve.
c. What influences the carrying capacity? Resources become limiting, death rate increases, birth rate
matches death (mortality) rate, food, water, habitat etc.
d. How do those features relate to the Malthusian catastrophe? Malthusian catastrophe says that there will
come a point where the number of resources will be less than the number of population. that point of
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Document Summary
Microevolution: evolution defined change in allelic frequencies, be familiar with at least six lines of evidence for evolution, homology - the state of having the same or similar relation, relative position, or structure. 4. 5 bya: what are the models of abiogenesis? (sponch k, oparin-haldane model reduction atmosphere (miller-urey conditions) makes biomolecules. This atmosphere, exposed to energy in various forms, produced simple organic compounds (monomers). By further transformation, more complex organic polymers and ultimately life developed in the soup: autocatalytic closure parts become whole. Populations grow at a faster rate than the rate resources are produced. Charles darwin: adaptation: (nature) differences: changes within a population, directly heritable through dna, built in. Unit ii: macroevolution: macroevolution - major evolutionary change. It occurs when two species from unrelated lines develop the same traits or features. Convergent evolution is the independent evolution of similar features in species of different lineages.
