Evolutionary Theory Review Flashcards
What is the unit called which makes up DNA?
Nucleotides
What are nucleotides made of?
A sugar group, a phosphate, and one of four nitrogen bases
What part of meiosis is most like mitosis? Explain.
Meiosis 2, both Mitosis and Meiosis 2 have sister chromatids.
What is a homologous pair and where do they come from
A pair of chromosomes containing the same genes. One homologous comes from the male parent and one from the female
Explain what a sister chromatid is.
Identical copies of a single chromosome that are attached to eachother. They are duplicated.
What are genes and where do you find them?
Genes are responsible for producing the proteins that run everything in our bodies. They are in the chromosome which is made up of DNA, molecules that contain genetic info
How are sister chromatids different from a homologous pair?
Sister chromatids are identical copies of a single chromosome. Homologous pairs are similar in shape and size but have different versions.
Explain what separates in a cell during Meiosis 1 and what is separating in during Meiosis 2?
In Meiosis 1, Homologous pairs of cells are separated into chromosomes. In Meiosis 2 the chromosomes separate into Sister chromatids.
What are different variations of a gene called?
An allele
The genes that are present in our chromosomes are collectively called what?
Genome
How these genes are expressed or seen is called our…
Phenotype
How many alleles for each gene are present in a gamete (sex cell)?
One allele
What is the term used to describe the number of chromosomes in a cell?
Haploid number
Explain how changing a nucleotide in your DNA can lead to evolution
If a trait is advantageous and helps the individual survive and reproduce
What are three examples of a phenotypic characteristic?
Height, eye colour, and blood type
Where would you find the alleles for a particular genetic trait, such as eye colour?
In homologous pairs/corresponding pairs
How many cells are produced during each stage of meiosis?
Two cells in Meiosis 1, 4 cell in Meiosis 2.
How many daughter cells are produced during meiosis?
Four daughter cells
If you have 40 chromosomes in your skins cells, what would the ploidy of your gametes be?
N=20
What are daughter cells called?
Gametes (egg, sperm)
What is haploid number of an organism with 20 chromosomes in their eye cells?
N=10
Explain why Meiosis is necessary during the process of sexual reproduction.
Must separate homologous pairs to insure that each gamete only has 1 allele for each gene. crossing over to increase genetic diversity
An organism which has two of the same alleles for the same gene is said to be…?
Homozygous
An organism which has two different alleles for the same gene is said to be…?
Hetrozygous
Upon what factor does Natural Selection act?
On Phenotypes or Physical characteristics.
(BLANK) is when different species develop similar traits as a result of living in similar environments.
Convergent evolution
When many different species evolve from a common ancestor, often due to a change in the environment, such as resources, it is called..?
Divergent evolution
What is mutualistic co evolution
When two species reciprocally affect each others evolution. When one species develops an evolutionary advantage it triggers a change in a closely associated species.
What is mutualistic coevolution?
Evolution in which both organisms benefit from each other.
What is competitive coevolution?
Competitive coevolution can lead to an arms race, in which two populations reciprocally drive one another to increasing levels of performance and complexity
What is convergent evolution?
Is the process where unrelated species, independently evolve similar traits as a result of having to adapt to similar environments or ecological niches
What is Divergent evolution
Is a process In which organisms diversify rapidly from an ancestral species into a multitude of new forms
What is the Hardy-Weinberg principle?
If a population isn’t evolving there is genetic equilibrium, meaning the allele frequencies are the same.
What conditions are required to maintain genetic equilibrium?
- No natural selection
- Stay mating within the population
- Neither migration or mutation are bringing new alleles to the population
- Very large population size (lowers effect of genetic drift)
What is Genetic Mutation?
A change in our DNA sequence due to mistakes when the DNA is replicated or environmental changes.
What can happen if there is a change in the Nucleotide Sequence?
Potentially creates new alleles for a trait which can result in new genotypes and phenotypes
What is Sexual Selection?
Another mode of natural selection, other things being equal, organisms more proficient in securing mates have higher fitness
How can Gene Flow (or Gene Migration) occur?
Occurs when genetic information from one population moves to another population.
How does Genetic Drift occur?
Occurs when chance or random events cause changes in the allele frequencies within a population.
What is the “Bottle Neck” effect?
When a population size is reduced for at least one generation.
How does the Founder Effect occur?
Occurs when a new colony is started by a few members of the original population.
What are the 4 variations of Evolution?
- Mutation
- Gene Flow
- Genetic Drift
- Natural Selection
What is Natural Selection?
When an organism adapts to their environment to have a higher chance of survival.
What are Beneficial phenotypes?
New alleles that make an organism more “fit” or better suited for survival.
What mechanisms can effect changes in alle frequencies?
Selection, mutation, migration, and genetic drift
