Natural Selection
The process of biological change in populations over time that makes descendants genetically different from their ancestors.
Evolution
increases the expression of an extreme version of a trait in a population.
1.Directional Selection: increases the expression of an extreme version of a trait in a population.
P =
Dominant
Where in the cycle we will be copying of all of DNA’s instructions
S- phase
Transcription –
Transcription – the process of making RNA from DNA; Purpose: To copy DNA’s genetic information into messenger RNA; Occurs in the nucleus of the cell
Evolution can occur on a small scale affecting a single population
Microevolution
a process that splits a population into two groups; removes individuals with average traits and favors the 2 extremes.
Disruptive Selection
Q =
Recessive
A goes with?
C goes with?
A goes with T
C goes with G
Meiosis – cell division that creates?
Meiosis – cell division that creates 4 haploid cells called gametes
Two Types of Evolution
Microevolution and Macroevolution
eliminates extreme expressions of a trait when the average expression leads to higher fitness.
Find frequency of homozygous recessive genotype.
q^2
unwinds and separates the 2 DNA strands by breaking the weak hydrogen bonds
Helicase
Genetic drift
Change in the gene pool caused by chance; tends to decrease a species’ genetic variation Example: Flood kills 95% of a worm population
Natural Selection is based on
Based on:
Overproduction of offspring
Variation
Adaptation
Descent with modification
Turtles that live on rocks and are grey will survive. Turtles that live on grass and are green will survive. Turtles that have an intermediate coloring would be disadvantaged because it would be more visible to predators.
Disruptive Selection
genotypic frequency of homozygous dominant individuals
genotypic frequency of heterozygous individuals
genotypic frequency of homozygous recessive individuals
•p2 = genotypic frequency of homozygous dominant individuals
•2pq = genotypic frequency of heterozygous individuals
•q2 = genotypic frequency of homozygous recessive individuals
Glue of the DNA replication
Ligase
Gene flow
Change in gene pool caused by movement of organisms into (increase genetic variation) or out of (decrease genetic variation) the population
Descent with Modification
Natural selection leads to populations with new phenotypes adapted to new situations.
The higher the frequency, the greater the?
The higher the frequency, the greater the allele is there (and the more common the trait is).
Allele Frequencies and Hardy-Weinberg Equilibrium equation
p2 + 2pq + q2 = 1
P + Q = 1
Insertion- a base pair is added to the gene.
Deletion- a base pair is removed from the gene
Enzyme
control the rate of chemical reactions by weakening bonds, thus lowering the amount of activation energy needed for the reaction
" Speed up"