Lesson 4.2 : Genetic Mechanisms of Population Change Flashcards
(17 cards)
a field of science that deals with genetic variation in the populations of organisms in the ecosystem
Population Genetics
molecules that make up DNA
Nucleotides
segments of DNA that regulate the expression of the traits of an organism through the identity and arrangement of the nucleotides
Genes
observable traits expressed in an individual
Phenotypes
refer to the variant form of a given gene
Alleles
events where changes in the genetic code or in the nucleotides of DNA occur
Mutations
Types of Mutations:
___ - increases the fitness of organisms
___ - decreases the fitness of organisms
___ - do not impact fitness
Advantageous Mutations
Deleterious Mutations
Neutral Mutations
the change of allele frequencies as a product of random events in the environment
Genetic Drift
refers to the loss of genetic variation in the new population that was established by a very few individuals from a larger population
Founder Effect
refers to the process where pieces of DNA are segmented and recombined to produce new combinations of alleles.
Recombination
the expression of certain traits in the organism is influenced and regulated by a set of genes
Genotype
abrupt reduction in the size of a population caused by random environmental events.
Bottleneck Effects
paired chromosomes
Homologous chromosomes
homologous chromosomes tightly joined together
Synapsis
Intersecting regions of chromatids holding the homologous together until separate in anaphase I.
Chiasmata
Who proposed the idea that “alleles must segregate somewhere between the production of sex cells and fertilization.”
Gregor Mendel
“All genes for all the traits of an offspring are equally distributed or segregated in all the resulting gametes after meiosis”
Law of Segregation
