12032254
Description
Mind Map by Dominic Weston, updated more than 1 year ago
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Created by Dominic Weston
almost 7 years ago
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Populations and Evolution
- Definitions
- Population
- Group of individuals belonging to the same species living in a particular area
- Group of individuals belonging to the same species living in a particular area
- Species
- Group of similar organisms that can reporduce to give fertile off spring
- Group of similar organisms that can reporduce to give fertile off spring
- Gene Pool
- Complete range of alleles present in a population
- Complete range of alleles present in a population
- Allele Frequency
- How often an allele occurs in a population
- How often an allele occurs in a population
- Population
- Hardy-Weinberg Principle
- Predicts that allele frequencies wont change from one generation to the next
- Only true if
- Large population
- That is isolated
- With No Mutations
- And No Natural Selection
- And there is Random Mating
- And there is Random Mating
- And No Natural Selection
- With No Mutations
- That is isolated
- Large population
- Only true if
- Hardy-Weinberg equations used to test whether or not ...
- Predicting Allele frequency
- p + q = 1
- p - Frequency of Dominant allele
- q - Frequency of Recessive Alleles
- 1 is the entire population
- p - Frequency of Dominant allele
- p + q = 1
- Predicting Genotype Frequency
- p^2 + 2pq + q^2 = 1
- p^2 is frequency of homozygous dominant
- 2pq is the frequency of heterozygous
- q^2 is the frequency of Homozygous Recessive
- p^2 is frequency of homozygous dominant
- p^2 + 2pq + q^2 = 1
- Predicting Allele frequency
- Predicts that allele frequencies wont change from one generation to the next
- Speciation
- Evolution of a species from an existing one
- Isolation Mechanisms
- Geographical
- Isolated by geographical barrier
- Isolated by geographical barrier
- Ecological
- Pop dont meet as inhabit different areas
- Pop dont meet as inhabit different areas
- Temporal
- Breeding seasons dont coincide
- Breeding seasons dont coincide
- Behavioural
- Any mutation that prevents courtship
- Any mutation that prevents courtship
- Mechanical
- Physical differences that prevent mating
- Physical differences that prevent mating
- Gametic
- Prevents gametes from meeting
- Prevents gametes from meeting
- Hybrid sterility
- Offspring of different species that are sterile
- Offspring of different species that are sterile
- Geographical
- Isolation Mechanisms
- Genetic Drift
- Can lead to Speciation
- Greater effect in small populations
- Where chance dictates
- who survives and breed to pass on alleles
- Rather than environmental factors
- Rather than environmental factors
- who survives and breed to pass on alleles
- Where chance dictates
- Greater effect in small populations
- Can lead to Speciation
- Two forms of speciation
- Allopatric
- When a geographical barrier seperates
- Two populations of the same species
- If environmental conditions are different between the two populations
- Natural selection will occur to favour optimal alleles
- Natural selection will occur to favour optimal alleles
- If environmental conditions are different between the two populations
- (Oceans, rivers, mountains, deserts)
- Two populations of the same species
- When a geographical barrier seperates
- Sympatric
- No geographical barrier
- Reproductive isolation still occurs
- Different timings of breeding seasons
- Different location preferences for mating or feeding
- Random mutation can prevent breeding between population
- Different timings of breeding seasons
- Reproductive isolation still occurs
- No geographical barrier
- Allopatric
- Evolution of a species from an existing one
- Natural Selection
- Process
- A new mutation arises in the population
- Slightly better adapted to the environment
- Due to overpopulation, only individuals who are better adapted will survive
- Individuals who survive are more likely to reproduce and pass on the alleles to the offspring
- Better adapted alleles become more common in the population over time
- Better adapted alleles become more common in the population over time
- Individuals who survive are more likely to reproduce and pass on the alleles to the offspring
- Due to overpopulation, only individuals who are better adapted will survive
- Slightly better adapted to the environment
- Link to context
- A new mutation arises in the population
- Process
- Variation in Phenotype
- Variation due to Genetics
- Mutations
- Meiosis
- Crossover of chromosomes
- Independent assortment
- Independent assortment
- Crossover of chromosomes
- Random Fertalisation of gametes
- Results in distinct characteristics
- Discrete data
- Discrete data
- Results in distinct characteristics
- Mutations
- Variation due to Environment
- Amount of light
- Infectious diseases
- Access to nutrients
- Access to nutrients
- Infectious diseases
- Continuous variations in characteristic
- Forms a normal-distruibution curve
- Forms a normal-distruibution curve
- Amount of light
- Variation due to Genetics
- Effects of different forms of selection on evolution
- Stabilising Selection
- Perserving the average phenotype of the population
- Selection against extremes in the population
- Usually when environmental conditions are stable
- Usually when environmental conditions are stable
- Selection against extremes in the population
- Perserving the average phenotype of the population
- Directional Selection
- Changes the phenotype to favour phenotype in one direction from the mean population
- E.g. Antibiotic Resistant Bacteria
- E.g. Antibiotic Resistant Bacteria
- Changes the phenotype to favour phenotype in one direction from the mean population
- Disruptive Selection
- Favours extreme phenotypes
- At expense of mean phenotype
- Mean can split into two extremes
- Due to environmental factors take two distinct forms
- Causes two distinct seperate species
- Causes two distinct seperate species
- Due to environmental factors take two distinct forms
- Mean can split into two extremes
- At expense of mean phenotype
- Favours extreme phenotypes
- Stabilising Selection
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