Class notes
Biol 1107 Evolution mechanism Notes
- Course
- BIOL 1107
- Institution
- University Of Georgia
This is a comprehensive and detailed note Evolution mechanism for Biol 1107. Enjoy!!
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Biology 1107 Unit 5 NotesEvolution
Part 3
Class Notes (Evolution Mechanisms)
- Sexual Selection
- Sexual selection is a form of selection that favors individuals with traits that
increase the ability to obtain mates (and sometimes significantly reduce the ability
to survive)
- Some are social signals for mating
- Asymmetry of sex is the idea that females will invest more energy in offspring
(eggs or parenting) than males in many species
- Females produce limited offspring and should select the most attractive
males
- Males produce unlimited offspring and should mate with any available
female
- Result will be competition between males
- These may be advantageous for mating but not for survival
- Ex) Peacocke
- Nonrandom Mating
- In addition to sexual selection, other forms of nonrandom mating can occur that
affect the genetic characteristics of a population
- Inbreeding (mating of individuals that are closely related to each other) is an
example
- Over time the number of heterozygotes in the population decreases while the
number of homozygotes increases
- Discussion Question
- Adaptations are traits that increase the fitness of individuals in specific
environments. Which evolution mechanism will lead to adaptations?
- Answer: Selection
, - Since adaptations of traits are favorable (positive) it has to be the selection
- Does inbreeding by itself cause evolution?
- Answer: No
- Allele frequencies are not changing, just the genotype frequencies
- Fossils reveal that extinct ancestors of anteaters had teeth. Why do modern
anteaters lack teeth?
- Answer: Teeth resulted in fewer offspring
Reading - Speciation
- Introduction
- New alleles are introduced in a population through mutation, gene flow, genetic
drift, and natural selection
- Change the allele frequencies and observed characteristics
- If the population is large or spread out across a wide area
- Different parts of the population change in different ways
- More likely to occur if alleles are unevenly distributed or when parts of
the population live in different environments
- Species Concepts
- Identifying species can be challenging
- Swedish botanist Carl Linnaeus in the 1700s
- Determining species based on observable traits is called the morphological
species concept
- Sometimes incorrectly identifies species
- Ex) Members of the same species can often display different phenotypes,
and members of different species can have a very similar phenotype
- Species is a group of organisms that interbreed and produce fertile offspring under
natural conditions
- Reproductively Isolated
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