Download Genetics & Evolution: Hardy-Weinberg, Species, Natural Selection, Polymorphism and more Quizzes Ecology and Environment in PDF only on Docsity!
Hardy-Weinberg Equilibrium
Allelic frequencies of a population with 2 alleles for a gene that is not experiencing the following:- Mutation- Migration- Natural Selection- Random Genetic Drift- Random Mating TERM 2
Founder Effect
DEFINITION 2 Loss of genetic variation as a result of starting off a population with a small number of individuals- E.g. going to mars with 10 people and creating a population of 1000 (high chance of imbreeding) TERM 3
Protozoa
DEFINITION 3 Large, diverse group of single-celled organisms TERM 4
Plasmodium
DEFINITION 4 Single-cell parasites that spread via mosquites TERM 5
Habitat/Ecological Prezygotic Mechanism
DEFINITION 5
- Species live in different ecological niches
Temporal Prezygotic Mechanism
- Species breed at different times TERM 7
Behavioral Prezygotic Mechanism
DEFINITION 7
- Species differ in their communications TERM 8
Mechanical Prezygotic Mechanism
DEFINITION 8
- Species differ in their copulatory mechanics TERM 9
Gamete Prezygotic Mechanism
DEFINITION 9
- Species have different receptor proteins TERM 10
Reduced Hybrid Viability Postzygotic
Mechanism
DEFINITION 10
Why don't we lose heterozygosity?
- Diploidy2. Balancing Selection- Natural Selection favoring balanced polymorphism- Two or more phenotypes maintained in stable proportions- Generally occurs when natural selection favours: - Heterozygotes - Different alleles favored in different environments TERM 17
Polymorphism
DEFINITION 17 The occurrence of different forms among the members of a population or colony, or in the life cycle of an individual organism TERM 18
Adaptive Evolution
DEFINITION 18
- Is not random- But a consequence of differential survival and reproductive success of individuals within a population (relative fitness)- Affects the phenotype (indirectly the genotype) TERM 19
Three Types of Natural Selection
DEFINITION 19
- Directional- E.g. cod fishing, older, larger fish are heavily targeted, overall age and size of fish decreases2. Stabilizing- Predators are 100% fed by the prey but the prey keeps reproducing3. Disruptive- TERM 20
Inbreeding Depression
DEFINITION 20
- Reduced biological fitness in a given population as a result of inbreeding (e.g. bottleneck, founder effect)
Goals of Conservation Genetics
To determine whether genetic management is required.1. How large is the effective population?- Population contributing to the next generation Ne = 4NefNem/(Nef+Nem)2. Has the population gone through a significant bottleneck(s)?3. Has the population lost genetic diversity?4. Is the population suffering from inbreeding depression?5. Is the population genetically fragmented? TERM 22
Genetic Drift
DEFINITION 22 Change in an allele frequency typically due to random events. TERM 23
Gene Flow
DEFINITION 23 The transfer of an allele from one population to another through hybridization and interbreeding. TERM 24
What is the purpose of a minimal viable
population?
DEFINITION 24
- Avoid inbreeding depression (small populations)- Retain single-locus genetic diversity (medium populations)- Retain Evolutionary Potential TERM 25
Natural History
DEFINITION 25 The study of flora and fauna. This is an observational science rather than experimental, presented in popular form (e.g. magazines, blue planet etc.) rather than academic form (scientific publications).
Linnaeus' Theory of Evolution
Evidence for the Theory of Descent (8)
DEFINITION 32
- Direct Observation2. Homology3. Fossil Record4. Biogeography5. Changes in Rate --> Allometric Growth6. Changes in Timing --> Heterochrony7. Changes in Spatial --> Hox Genes8. Changes in Gene Regulation & Pre-Adaptation (Co-Option) TERM 33
Pesticide Treadmill
DEFINITION 33
- Pest Problem2. Pesticides introduced3. Kills off all except a few4. Increased resistance due to natural selection5. Secondary outbreak6. Higher quantities of pesticides used7. Cycle Repeats TERM 34
Mutations that lead to New Genetic
Variation
DEFINITION 34
- Neutral2. Deleterious3. Lethal4. Advantageous TERM 35
Hardy Weinberg
Assumptions
DEFINITION 35
- Large Population- No immigration- Random Mating- No mutations- All GENOTYPES have equal fitness (equal chance of survival)
Gynogenetic Population
- Population of only females- Produces diploid eggs- Requires sperm from another species to fertilize eggs - E.g. Amazon Molly TERM 37
Androdioecies Population
DEFINITION 37
- Population that consists mostly of hermaphrodites- Reproduces via self fertilization - E.g. mangrove killfish TERM 38
Ring Population
DEFINITION 38
- A group of populations of somewhat isolated subspecies which can interbreed with each other but not with the extreme ends of the ring TERM 39
Hybrid Population
DEFINITION 39
- Two species interbreed that produce viable and fertile offspring TERM 40
Problems with the Biological Species
Definition
DEFINITION 40
- Hybrid Populations (two species creating fertile hybrids)2. Ring Populations3. Gynogenetic Populations (all female)4. Androdiocies Populations (hermaphrodites)
Reticulate Evolution*
- Formation of new lineage through partial merging of two ancestral lineages TERM 47
Orthologous Genes
DEFINITION 47
- Looking at the gene of comparison and the number of nucleotide differences- Genes in different organisms similar in their nucleotide sequence, suggesting common ancestry TERM 48
Paralogous Genes* Needs example
DEFINITION 48
- A gene that is duplicated in a chromosome- One end evolves in one way, one evolves anotherE.g. Hemoglobin and the protein that evolved from hemoglobin TERM 49
What is the difference between a phylogram
and a cladogram?
DEFINITION 49 A cladogram looks at the events of evolution and divergence starting with a common ancestorA phylogram tells you when those evolutionary events happened by looking at the number of nucleotide differences (assuming a constant rate of mutation), starting with the living species and working back to a common ancestor. TERM 50
Nei's index of genetic
distance
DEFINITION 50
- Used to determine whether a population is genetically fragmented or not
Convergent Evolution
- Organisms that are not closely related evolve similar characteristics as they adapt to the same environment- Analogous: not a result of common ancestry but the analogous traits share the same function TERM 52
Cuvier
DEFINITION 52
- Invented paleontology- "Species can go extinct" TERM 53
Lamarck's Theory
DEFINITION 53 Theory of Acquired Characteristics- Use and disuse, traits that were used got stronger, those that were not, deteriorated (giraffe's neck stretching)- These stronger and weaker traits that an organism gained over its life could be passed on to its offspring- Organisms have an innate drive to become more complex TERM 54
Balancing Selection
DEFINITION 54
- Maintaining two or more phenotypes stably TERM 55
Heterochrony
DEFINITION 55
- Change in rate of growth resulting in speciation- Adults retaining juvenile characteristics - Are humans just paedomorphic chimps?
