Topic 11 Flashcards
Which of the following causes evolutionary change, individuals mating with phenotypically similar mates?
Nonrandom Mating
Which of the following are not agents of evolutionary change?
Gene flow
Mutations
Random mating
Genetic Drift
Selection
random mating
Fitness is defined in a particular population would be considered of which of the following?
The number of surviving offspring left in the next generation
Founder effects and bottlenecks are examples of what?
forms of genetic drift
In order for evolution to occur by selection which of the following must take place?
Phenotypic variation must exist among individuals
Variation among individuals must result in differences in the number of offspring surviving in the next generation
Phenotypic variation must have a genetic basis
All of the above
all of the above
Which of the following causes evolutionary change, by the random fluctuation in allele frequencies in populations over time by change?
genetic drift
Which of the following causes evolutionary change, due to the movement of certain alleles into or out of one population to another?
gene flow
The Hardy-Weinberg principle states which of the following?
Genotype proportions do not change but remain constant, under certain assumptions
Allele frequencies in population genetics is measuring what?
The occurrence of individual alleles expressed in an entire population
For natural selection to result in evolutionary change which of the following must occur?
reproductive success of different phenotypes must differ
variation must exist in a population
variation must be inherited from one generation to the next
All of the choices are correct
all of these choices are correct
Define and list the difference between Lamarch’s and Darwin’s Theory of Evolution/Natural Selection?
Darwin’s theory of natural selection – states that evolutionary changes occur when certain individuals produce more surviving offspring’s due to their advantageous characteristics.
Lamarck’s theory -Evolution occurred by the inheritance of acquired characteristics, that organisms acquire changes during their lives that can be passed on to their offspring’s, allows evolutionary adaptations.
Define and list the conditions needing to be met for the Hardy-Weinberg Principle to be at equilibrium, and how does this help us to understand evolution?
- no mutations take place,
- no genes are transferred to or from other sources (no immigration or emigration takes place),
- Mating is random ( individuals do not choose mates based on their phenotype or genotype),
- Population size is very large,
- no selection occurs.
genotypes’ proportions do not change, and remain constant from generation to generation, and why genetic variation persists, as long as the previous assumptions are met
Jean-Baptiste Lamarch Theory,
Evolution occurred by the inheritance of acquired characteristics, that organisms acquire changes during their lives that can be passed on to their offspring’s, allows evolutionary adaptations
Charles Darwin Theory,
states that evolutionary changes occur when certain individuals produce more surviving offspring’s due to their advantageous characteristics
Hardy-Weinberg Principle
genotypes’ proportions do not change, and remain constant from generation to generation, and why genetic variation persists, as long as the following assumptions are met:
no mutations take place,
no genes are transferred to or from other sources (no immigration or emigration takes place), Mating is random (individuals do not choose mates based on their phenotype or genotype), Population size is very large, no selection occurs.
Genetic Variation,
refers to the different alleles of genes found within individuals of a population.
Allele,
one of two or more alternative states of a gene
Phenotype,
the realized expression of the genotype; the physical appearance or function expression of a trait
Genotype,
is the genetic constitution underlaying a single trait or set of traits in an individual.
Allele Frequency,
is the measure of the occurrence of each individual allele in a population, expressed as proportion of the entire population, from one generation to the next generation. Allele frequencies can change when mutations, changing of one allele for another, or gene migration brings alleles into a population.
Biological concept of species,
is that each species exchanges genes with other members of its species.
says that a species is composed of populations whose members mate with each other and produce fertile offspring
Reproductive isolation,
Pre-Zygotic Reproductive barriers
Ecological Isolation – Species occur in the same area, but they occupy different habitats and rarely encounter each other.
Behavior Isolation – Species mating behavior/rituals differ preventing their mating.
Temporal Isolation – Species reproduce in different seasons or at different times of the day.
Mechanical Isolation – Structural differences between species prevent mating.
Prevention of Gamete fusion – Gametes of one species function poorly with the gametes of another species or within the reproductive tract of another species.
Post-Zygotic Reproductive barriers
Hybrid inviability or infertility or Hybrid breakdown – Hybrid embryos do not develop properly, hybrid adults do not survive in nature, or hybrid adults are sterile or have reduced fertility
Speciation,
Speciation is the process by which new and distinct species are formed in the course of evolution. A species is a group of organisms that can interbreed and produce fertile offspring. Speciation occurs when groups within a species become reproductively isolated and diverge
Ecological Isolation,
Species occur in the same area, but they occupy different habitats and rarely encounter each other
Behavior Isolation,
Species mating behavior/rituals differ preventing their mating.
Temporal Isolation,
Species reproduce in different seasons or at different times of the day
Mechanical Isolation,
Structural differences between species prevent mating
Gamete Fusion,
Prevention of Gamete fusion – Gametes of one species function poorly with the gametes of another species or within the reproductive tract of another species
Hybrid inviability/Infertility,
Hybrid embryos do not develop properly, hybrid adults do not survive in nature, or hybrid adults are sterile or have reduced fertility
Taxonomy,
is the branch of science that deals with the classification of organisms.
Specific scientific name are given to each species, called binomial name, consisting of a genus and species.
Human: Genus = Homo; species sapiens.
Dogs: Genus = Canine; Species = Lupus.
Cladistics,
is a type of taxonomic systematists, that classifies species based on similarities that arise most recently, and not inherited from the most recent common ancestor of the group.
In this approach, only shared derived characters are considered informative in determining evolution relationships.
Phylogenetics,
uses modern genetics and biochemical analyses, reveals relatedness among diverse organisms, looking at the changes in genetics and modifications in amino acid sequences in genes.
Hardy-Weinberg Principle/Equilibrium,
genotypes’ proportions do not change, and remain constant from generation to generation, and why genetic variation persists, as long as the following assumptions are met:
no mutations take place,
no genes are transferred to or from other sources (no immigration or emigration takes place),
Mating is random ( individuals do not choose mates based on their phenotype or genotype),
Population size is very large,
no selection occurs.
Frequency-dependent Selection,
in some circumstances, the fitness of a phenotype depends on its frequency within the population, and this type of selection favors certain phenotypes depending on how commonly or uncommonly they occur, and can be positive or negatively impacting
Stabilizing Selection
is a type of selection that acts to eliminate both extremes from an array of phenotypes, and results is to increase the frequency of the already common intermediate.
