Unit 1: Evolution I and II Flashcards
Who is the famous scientist who observed variation in finches?
Charles Darwin
What was the name of Darwin’s voyage?
Voyage of the Beagle
What was Darwin’s publication?
“On the Origin of Species”
Darwin best described biological evolution as what?
Descent with modification through variation and natural selection
Variation
Variation within species
Natural Selection
Population change over time where individuals with favorable traits pass them onto offspring in an effort to maintain survival
Evolutionary Adaptation
Form of evolutionary change in which a population’s characteristics change to suit environment
What is the main difference between microevolution and macroevolution?
Microevolution relates to changes in a single gene in a population over time, whereas macroevolution is the cumulation of changes in genes that results in the formation of a new related species
A population of organisms is described as NN, Nn, and nn. What are the genotypic meanings of these?
NN: Homozygous dominant
Nn: Heterozygous
nn: Homozygous recessive
Darwinian Fitness is best described as the _____ of likelihood that a _____ will contribute to the ____ ____ of the next ____ as compared with other genotypes. It is a measure of ____ success and the average of members in a population is called the _____ _____ of the population.
relative; genotype; gene pool; generation
reproductive; mean fitness
What are the four classes of evolutionary mechanisms?
Selection, random genetic drift, gene flow, and non-random mating.
What is the relationship between heritable variation and environmental factors?
Heritable variation is where survival depends partially on inherited traits. Environmental factors filter heritable variations where favoritism is swayed to others.
True or False:
An organism is the smallest unit of evolutionary change.
False – natural selection acts on individuals, but evolution acts on the population
True or False:
Natural selection can only act on heritable traits AND it is a creative tool.
False – while natural selection does only act on heritable traits, it is a remodeling tool, not a creative one.
What are the three tenants for natural selection to occur?
- Variation must exist among individuals in a population.
- Variation among individuals must result in differences in the number of offspring surviving in the next population.
- Variation must be genetically inherited.
Match the following letters with its number:
A: directional
B: stabilizing
C: disruptive
D: balancing
E: sexual
1: intermediate favoritism
2: extreme favoritism
3: more favoritism on ends
4: advantage over others in same sex and species
5: maintains genetic diversity
A:2
B:1
C:3
D:5
E:4
Describe heterozygote advantage and give an example.
Heterozygote advantage: heterozygous genotype is promoted
Example: malaria (AA get it, AS “immune,” SS have sickle-cell anemia)
Intrasexual Selection
Selection between members of the same sex; male-male competition
Intersexual Selection
Selection between members of the opposite sex; female choice
Sexual Dimorphism
Sexual selection acts on males more strongly than on females
Explain genetic drift and provide two examples.
Genetic Drift: when allele frequencies fluctuate randomly from one generation to another, and favors either loss or fixation of an allele.
Examples: bottleneck effect; founder effect
Gene Flow
When emigration or immigration causes alleles to be gained or lost
How is gene flow different from genetic drift, especially the founder effect?
In genetic drift, allele frequency is changed within that population without mixing with another population. Gene flow is a change in allele frequency due to movement into or out of a population.
Assortative Mating
Mating where individuals with similar phenotypes are more likely to mate, results in increases of homozygous genotypes
Disassortative Mating
Mating where individuals with dissimilar phenotypes mate, increases proportion of heterozygous phenotypes
Inbreeding
Mating between genetically related individuals; results in increase in homozygous genotypes and usually occurs in small populations
How does the fossil record assist in the field of evolutionary biology?
The fossil record is a vast collection of preserved body parts of past and ancient organisms where species could be extinct or extant. It helps in showing changes such as larger size and complexity in teeth development.
Developmental Homology
Homology that looks at early development of different species to draw on homologous strictures that have different functions
Anatomical Homology
Homology looking at organisms and how they have similar structures across anatomical structures, but different functions
Molecular Homology
Homology that looks at similarities among organisms at the molecular level
Vestigal Structures
Organs not needed by the organism that are remnant of important structures in ancestors
Example: wisdom teeth, appendix
Biogeography
Study of geographical distribution of extinct and modern species
Convergent Evolution
When species from different lineages show similar characteristics because they occupy similar environments
What species is the main driving force behind artificial selection?
Humans
