Definitions Flashcards
What is a monohybrid cross?
One trait, one gene, two alleles.
3:1 ratio.
What is a dihybrid cross?
Tow traits, two genes, four alleles.
9:3:3:1 ratio.
What are mendels laws?
First law: alleles of a single gene segregate equally into gametes.
Second law: alleles of different genes segregate independently into gametes.
What is allopathic speciation?
Speciation by geographic isolation.
Describe alturism.
Behaviour that decreases the fitness of the individual but increases the fitness of recipient.
Define the bottleneck.
A sharp reduction in population size due to environmental or human activities. Reduces gene pool variation.
Define sympatric speciation.
New species evolve from a single ancestral speices in the same geographical region.
Describe disruptive selection.
Diversifying election, population genetics changes where extreme values are favoured.
What is Hamiltons rule?
rb>c
Evolutionary strategy that favours reproductive success of relatives.
What is inclusive fitness?
Evolutionary success of a trait can be calculated as:
Sum of fitness x relatedness
What is the neutral theory?
At the molecular level most evolutionary changes and the variability are caused by random drift not selection.
What is phylogeny?
The history of the evolution of a species or group.
What is polyandry?
Mating where the female mates with more than one male.
What is Postzygotic isolation?
Prevent hybrids from passing on genes ny reproductive isolation after fertilisation.
What is a transitional form?
Organisms that show intermediates between ancestral descendents.
What is morphospecies?
Populations designated as seperate species based on differences in form.
What is natural selection?
Organisms best adapted to their environment tend to survive and transmit genetic characters on to offspring.
Define genotype.
The genetic makeup of a cell, organism or individual.
Define phenotype.
The observable physical or biochemical characteristics of an organism based on genetic makeup and the environment.
What is allele frequency?
The proportion of a particular allele among all allele copies being considered.
Define speciation.
The evolutionary process by which new species arise.
What is a missing link?
Usually a fossilised remain of a life form that exhibits traits common to its ancestors and descendants.
What is an Endemic species?
A species with a habitat restricted to one area.
What is a pandemic species?
A species widely distributed throughout a country or continent.
What is convergent evolution?
The independent evolution of similar features in species of different lineages.
What is a molecular clock?
A technique that uses fossils and rates of molecular change to deduce the time when two species diverged.
What Is a synonymous change in dna?
Substitution of one base for another that doesn’t change the primary structure.
What is junk dna?
Dna that doesn’t code for proteins or their regulation.
What was the cambria explosion?
The rapid appearance of most major animal phyla around 542 m years ago.
What is genetic drift?
Random changes in allele frequencies caused by sampling error.
What is the founder effect?
Genetic drift resulting from the establishment of a new population by a small number of individuals.
Define fitness.
The ability to both survive and reproduce and equals the average contribution to the gene pool of the next generation.
What is social evolution?
Social behaviours having fitness consequences for others, not the actor (alturistic or selfish)
What does analogous mean?
Similarities Due to adaption to similar environmental problems not common descent (convergent evolution).
What does homologous mean?
Similar structures between species as the result of descent from a common ancestor (convergent evolution)
What is fixation?
The state where the individual in a population has the same allele at the particular locus.
What is gene flow?
The movement of alleles between populations.
What is a gene pool?
All the alleles in a breeding population at one time.
Define aneuploidy.
An abnormal number of chromosomes.
What is trisomy?
Three chromosomes instead of two.
What is polygyny?
Where a male mates with more than one female.
What is heredity?
The study of inheritance.
What is population genetics?
The study of the gene pool of a organism.
What is molecular genetics?
The study of the molecular structure and function of genes.
