BIO 311D EC Map

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Evolution: Natural Selection

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Exam II Topics

Convergent Evolution

Examples -Sharks, Penguins and Dolphins In all 3 lineages, natural selection favored adaptations that promote rapid swimming. They show superficial similarities in body structure.

development of phenotypic similarities between distantly related taxa

They just become more similar because of the environment acting on them

-Species cannot exchange genes; they don’t share the same genetic variation

Nothing to do with hybridization

Adaptative Radiation

development of a new species from a common ancestor due to adaptations to different environments

Character displacement

selection occurs in different directions

Has a zone of overlap, reducing competition not related to hybridization

As species converge toward each other some characteristics start to differ so there is less competition ex. Beak Size of similar bird species

Speciation is the evolutionary process by which new biological species arise.

Allopatric Geographical Speciation

4. reproductive isolation present without geographical barrier. speciation is complete

3. selection causes divergence in gene pools

2. gene flow interrupted variant types appear

1. two populations experience gene flow

Two models of allopatric speciation:

dumb-bell

peripheral

Exam I Topics

Inbreeding: Inbreeding is reproduction from the mating of parents who are closely related genetically

Inbreeding Depression

2. bringing together harmful genes related by decent

Subtopic

1. organisms are geared towards heterozygosity (good)

every generation of self-fertilization (“selfing”), heterozygous decreases by half

self-fertilization is the most extreme form of inbreeding

Gene Flow: (migration): movement of individuals between established, existing populations

equation to measure changes in allele frequency with immigration or emigration: q = M(qimm) + (1-M)(qoriginal) M = migration rate = migrant population / final population total

admixture: proportion of a genetic distance one population moves towards the other 1. level of admixture increases as populations genetically converge over generations

gene pool: allele frequency along all loci; gene frequencies will not revert back to original after migration

Genetic Drift

founder effect: loss of genetic variation when a new population is established by a small number of individuals from a larger population (chance deviation)

random changes in gene frequencies from one generation to another

Mutations are random changes in genetic cod. Responsible for:

for men its age dependant

95% of all mutations are harmful

Generating new alleles

ultimate source of genetic variation

Exam III

Biological Control

reproductive control release of sterile insects use of chemical sterilants release of incompatible pest strains

hormones pheromones or behavioral chemicals

by other organisms parasites, predators, pathogens

Niche Overlap And Competition

How species reduce competition

● when different species use the same resource they behaviorally reduce niche overlap to reduce competition ○ warbler example: each species of warbler spends most of its time in a designated area

resource partitioning (behavioral mechanism) - dividing resources

barnacle example: the chthamalus has a fundamental niche greater than its realized niche because of competition with the balanus. ● In a graph plotted range diet vs range habitat of two species a. as the overlap of the two species increases so does the level of competition, the larger the range diet/range habitat -> more overlap -> more competition

he greater the similarity in requirements between two species, the greater the niche overlap

BIO 311D EC Map

I didnn't know how to indicate relationships between different exams by using the lines since this is a new software for me so I decided to type out the relationship of the ideas I have chosen. The three exam topics are related as they all factor in controlling population aspects especially size of the population. Exam One focused on how genetically populations are altered and controlled while Exam II focused on what happens when species interact. Lastly Exam III focused on specifically competition and how species must adapt in order to coexist. Basically the three exams show how the populations essentially alter contonously over time in order to keep up with the ever growing nature of biological species.

Saad Mallick