Unit 2: Lectures 9-13 Flashcards
The sharp reduction in size of the population due to the environmental factors such as floods, earthquakes, lethal diseases, etc.
Bottleneck effect
Main characteristics of DNA described by Watson and Crick
Double helix structure (2 polynucleotides)
Strands are complementary and connected by hydrogen bonds (4 nitrogenous bases)
Antiparallel
Limits of natural selection
Selection can act only on existing variation in population
Historical constraints
Usually compromise
Interacts with chance and are random
The drifting frequency of an allele in a population over time as a result of chance or random event
Genetic drift
Why genes can be implanted in another species
Genetic code is nearly universal for all organisms
Important characteristics of the genetic code to prevent mistakes in protein synthesis
Redundant: has more than one codon for each amino acid
Not ambiguous: Each codon only codes one amino acid
How meiosis and sexual reproduction increases/maintains genetic diversity
Independent orientation of chromosomes
Random fertilization
Crossing over
Exchange of genetic information
crossing over
Physical appearance as a result of alleles
Phenotype
One of the possible forms of a gene
allele
Inheritable characteristics that give organisms a better chance at survival and reproductive success through abiotic and biotic interactions with the environment
Adaptations
What mechanism of evolution is most likely tolead to adaptive evolution
Natural selection
Alleles present in offspring for characteristic (a set of genes in our DNA which is responsible for a particular trait)
Genotype
Recessive
Masked by dominant allele, but only determines appearance if both alleles are recessive (aa)
How do changes in population occur by natural selection?
Individuals with characteristics allowing them to be better at getting food, escaping predators, tolerating the environment, and mating, will survive and reproduce, passing those genes to their offspring
