Lecture 7- Inheritance and Evolution Flashcards
The explanation for the unity and diversity of organisms is
evolution
evolution definition
the concept that living organisms are modified descendants of common ancestors
Biological evolution is
the change is allele frequencies in a population over time
Populations evolve as
allele frequencies change
every individual that is born/ dies and every individual that migrates affects
allele frequencies
Charles darwin described
natural selection
Darwin’s observations
- individuals in a population vary their traits which seem to be heritable
- a population produces more offspring than can survive to reproduce themselves
- species generally are suited to their environment
natural selection
individuals with inherited traits that are better suited for reproduction/ survival are more likely to pass those traits on
Darwin’s postulates
- variation exists among individuals that make up a population
- trait differences are heritable
- survival and reproductive success are variable
- individuals that survive best and produce the most offspring are not a random sample
units of inheritance
genes
genes encode information for
building the molecules synthesized within the cell
the genetic info encoded by DNA
directs the development of an organism
gene expression
the process of converting information from gene to cellular product
hybridization
the crossing of two true-breeding individuals from different varieties.
law of segregation
two alleles in a pair segregate into different gametes during gamete formation
law of independent assortment
each pair of alleles segregate independently from any other alleles
the ratio of phenotypes in dihybrid cross (F2 generation)
9:3:3:1
Chi-squared test tests
if there is a significant difference between the expected vs the observed proportions
How to sort three different alleles
three different punnet squares and treat them as independent events (multiply probabilities)
Incomplete dominance
phenotype of heterozygotes is intermediate between the phenotypes of homozygous groups (three phenotypes)
Codominance
phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate ways.
