Mechanisms of Evolution
... • A change in the population because of a
random event, such as a catastrophe
• The smaller the population, the less
genetic variety it has.
• 2 Types:
15.2 PDQ - Biology with Radjewski
... 2. Explain, “natural selection acts on
individuals, but populations evolve”
• Changes that occur are developmental in a
single organism over the course of a life cycle.
• After breeding populations will evolve
... interbreeding but have different
mating rituals or routines. i.e.
eastern & western meadowlarks
More Evolution and Hardy Weinberg! KEY
... Decrease in the population due to some environment disaster, genetic drift
3. What is the founder effect? This is an example of which mechanism?
Individuals that have been isolated, they evolve based on the environment
4. True or false:
Genetic drift can cause allele frequencies to change randomly: ...
doc 3.7.3 evolution checklist
... Reproductive separation of two populations can result in the accumulation of difference in
their gene pools. New species arise when these genetic differences lead to an inability of
members of the populations to interbreed and produce fertile offspring. In this way,
new species arise from existing s ...
... genetic constitutions of organisms by their selection of plants and animals in the new
activity of agriculture .The breeding of domesticated species of plants and animals
involves artificial selection and natural hybridization between related species and the
doubling of whole sets of chromosomes to ...
... differential survival of
groups of organisms
16-1 Genes and Variation
... species in a given area. (Share a common gene pool)
Gene pool—combined genetic info of all members
of a population.
Relative frequency—is the number of times an
allele (T) occurs in a gene pool compared with the
number of times other alleles (t) occur.
Causes of Evolution
... Types of Natural Selection
1. STABILIZING Selection = favors average individuals in a population
• reduces variation in organisms
Ex: lizards – large captured easily & small cannot run fast enough
2. DIRECTIONAL Selection = favors one of the extreme variations of a trait
• can lead to rapid evolutio ...
Enriched Biology Dremann Metzendorf Bag 3
... 5. All the genes of all members of a particular population make up the
6. In a population, the sum of the relative frequencies of all alleles for a
particular trait is…
7. A change in a sequence of DNA is called a…
8. The two main sources of genetic variation are…
9. In genetic drift, ...
Population Genetics and evolution with notes
... Darwin developed his theory of natural
selection before knowledge of genetics
Populations evolve, not individuals!
An organism is born with its phenotype, and it never
changes during its lifetime
Evolution occurs as a population’s genes and their
frequencies change over time
Gene Pool: all of th ...
Quiz 3, February 6, 2003
... a. MUTATION is the original source of genetic variation within populations.
b. NATURAL SELECTION is a process by which individuals with particular heritable
characters survive and reproduce at a higher rate than other individuals in a population.
c. GENETIC DRIFT is a random process that is most inf ...
Evolutionary forces: in small populations
... 1. Mutation: the only source of new genetic information.
Mutation: any heritable change in the structure or amount of
Different levels of mutation
DNA: point and frame shift mutations (mistakes made
during DNA replication)
Arrangements of DNA
+/- of single chromosomes
+ complete se ...
... traits in a population over several
Evolution is only apparent when a population
is tracked over time
Adaptation and Speciation
... recombined to produce new combinations of
This recombination process creates genetic
diversity at the level of genes that reflects
differences in the DNA sequences of different
... Biology 6C
... increased fitness.
Most mutations are
Biology First Six Weeks Vocabulary
... The total number of fossils, and their locations in rock formations and sedimentary
layers which provides information about those organisms
Microevolution is the change in allele frequencies that occur over time within a population. This change is due to four different processes: mutation, selection (natural and artificial), gene flow, and genetic drift. This change happens over a relatively short (in evolutionary terms) amount of time compared to the changes termed 'macroevolution' which is where greater differences in the population occur.Population genetics is the branch of biology that provides the mathematical structure for the study of the process of microevolution. Ecological genetics concerns itself with observing microevolution in the wild. Typically, observable instances of evolution are examples of microevolution; for example, bacterial strains that have antibiotic resistance.Microevolution over time leads to speciation or the appearance of novel structure, sometimes classified as macroevolution. Macro and microevolution describe fundamentally identical processes on different scales.