Unit One Flashcards
Evolution
the change in frequency of an allele from one generation to the next
Gene
stretch of DNA that codes for a protein which is wrapped up on a chromosome
Locus
spot on a chromosome that codes for a gene
Allele
different versions or forms of a gene
Genotype
whole genetic makeup of an organism
Phenotype
expressed, sometimes physical traits of an organism
Species
a group of individuals that can share alleles & exchange genetic material
Gene pool
Some combination of alleles
Population genetics
study of patterns of genetic variation
Population
a group of the same species in the same area
DNA
double helix molecule made up of nucleotides
Nucleotides
building blocks of DNA
Chromosome
a structure within the nucleus of a cell that contains an organisms genetic information
Diploid
a set of chromosomes (2n)
Haploid
lone chromosome (n)
Gametes
a haploid cell that needs to fuse with another haploid cell to make a new organism (sex cells)
Fertilization
two haploid cells create a diploid cell (i.e. sperm and egg create zygote)
Mitosis
2n reproduces to make another 2n (i.e. skin cells reproducing)
Meiosis
2n reproduces to make n (i.e. occurs in germ cells)
Mutation
a change in one of the nucleotides in the DNA
Germ-line mutation
mutation in meiosis
Somatic mutation
Mutation in a non germ-line cell
Recombination
occurs through crossing over
Deleterious
mutation that is harmful to the organisms survival
Adaptation
a genetic change that allows an organism to better survive and reproduce in its environment
Allele frequency
a measure of how rarely an allele occurs
Genetic drift
similar to sample error or error in representation
Darwin’s Postulates
- All organisms show variation
- All species produce more offspring than can survive
- Individuals with favorable traits tend to survive and reproduce, passing favorable traits to offspring
- Result is a favorable change in traits in the population
- Over time, this leads to populations becoming adapted to their environment
What makes a favorable trait?
The ability to survive and reproduce
Adaptation
has to be a genetic change that helps an organism survive and reproduce
Fitness
how well an individual’s genotype is represented in the next generation
Complex
not an either/or trait
Modern Synthesis
modern understanding of genetics and evolution put together
Stabilizing selection
selects against the extremes
Directional selection
selects against one of the two extremes
Disruptive selection
selects against the mean
Sexual selection
promotes an individual’s access to mating
Gene flow
moving around is causing a change in allele frequencies
Biological Species Concept
Defines species as a group of interbreeding populations that are reproductively isolated from one another
Ecological Species Concept
Organisms that can biologically reproduce but occupy different niches so they likely would choose not to interbreed
Competitive Exclusion Principle/Gause’s Law
Two species cannot fill the same ecological niche at the same time
Evolutionary Species Concept
End of a branch on a cladogram is a species
Pre Zygotic Isolation
Gene flow is stopped. This occurs before a zygote is formed
Pre-Zygotic Isolation can include…
Behavioral, biochemical, anatomical, temporal, spatial
Post-Zygotic Isolation
a form of genetic incompatibility, often caused by a differing number of chromosomes
Vicariance
a geographical separation of a population
Dispersal
A population migrates to another location and evolves separately from the original population
Peripatric
A population moves to a smaller location and evolves separately from the original population
Adaptive Radiation
a population rapidly evolves and diversifies (Darwin’s finches)
Allopatric Speciation
a process where a single species splits into two or more genetically distinct lineages due to geographic isolation
Co-speciation
two organisms speciate at the same time
Sympatric Speciation
a process in evolutionary biology that occurs when a new species evolves from an ancestral species while both continue to live in the same area
Types of Sympatric Speciation
Stabilizing, Directional, Disruptive
Instantaneous Speciation
hybridization between sunflowers
Roots of eukaryote
eu=good/true, kary=kernel(referring to nucleus), pro=first
