Ch. 8 - Evolution Flashcards
Microevolution: changes in ____ that occur over time within a ____ (due to mutation, selection, gene flow & drift)
____
allele frequencies
population
Macroevolution: patterns of changes in ____ over broad periods of geologic time. Patterns determine ____ (evolutionary relationships among species and groups of species).
groups of related species
phylogeny
Lamarck theory:
- Use and disuse: ____ can develop with increased usage, unused parts are weakened (____ in athletes).
- Inheritance of acquired characteristics: body features acquired during lifetime can be ____ (____, since only changes in genetic material of cells can be passed to offspring).
- Natural transformation of species: organisms produced offspring with changes, transforming each later generation ____ (no ____ or splits into more species) => ____.
- Natural selection: survival of the fittest (Darwinism) => now called ____ (synthetic theory of evolution).
body parts
correct
passed down to offsprings
incorrect
slightly more complex
extinction
incorrect
neo-Darwinism
EVIDENCE FOR EVOLUTION:
1. Paleontology: ____ reveal prehistoric existence of extinct species; often found in sediment layers (deepest fossils
represent oldest specimens). (____ produce new species)(fos types: actual remains, petrification, imprints, molds, casts)
fossils
large, rapid changes
EVIDENCE FOR EVOLUTION:
2. Biogeography: geography to describe ____; unrelated species in different regions of world look alike
when found in ____.
____ – supercontinent Pangea slowly broke apart to 7 continents
distribution of species
similar environments
continental drift
- EVIDENCE FOR EVOLUTION:
Embryology: similar stages of development (____) among related species => establish evolutionary relationships
(____). Gill slits and tails are found in fish, chicken, pig, and human embryos.
“ontogeny recapitulates phylogeny” – this specific recapitulation theory is considered ____, basically said that embryological stages represent our past evolutionary ancestors .
ontogeny
phylogeny
defunct
EVIDENCE FOR EVOLUTION:
4. Comparative anatomy: describes two kind of structures that contribute to identification of ____.
a. Homologous structure: body parts that resemble one another in ____ species from ____.
b. Analogous structure: body parts that resemble one another in ____ species because they evolved
____ as adaptation to their ____.
evolutionary relationship
different
common ancestor
different
independently
environments
EVIDENCE FOR EVOLUTION:
5. Molecular biology: examines nucleotide and amino acid sequences of DNA and proteins from different species. More
than 98% of nucleotide sequences in humans and chimpanzees are identical. AA’s in ____ often compared.
cytochrome c
EVIDENCE FOR EVOLUTION:
6. Comparative biochemistry: Organisms w/ common ancestor = common ____
biochemical pathways
B. Natural Selection: responsible for producing adaptations (____ ) that increase individual’s fitness (____ )
- Populations possess an enormous reproductive potential: if all offspring produced and survived.
- Population size remain stable: populations generally fluctuate around a constant size.
- Resources are limited: resources do not increase as population grow larger.
- Individuals compete for survival: growing pop will exceed available resources => compete.
- There is variation among individuals in a population: such as skin color (very pale to very dark).
- Much variation is heritable: DNA passed down.
- Only the most fit individuals survive: survival of the fittest.
- Evolution occurs as favorable traits accumulate in the population: best adapted individuals => best adapted offspring leave most offspring.
superior inherited traits
ability to survive, leave offspring
Stabilizing selection: bell curve (average height in human is in middle), favors an ____(all selections shown)
intermediate
Directional selection: favors traits that are at ____ of a range of traits. Traits at opposite extremes are ____.
After many generations => changes in allele frequencies (such as ____).
- Industrial melanism: selection of ____ (melanic) varieties in various species of moths (peppered moth) as a result of ____.
one extreme
selected against
insecticide resistance
industrial pollution
____: occurs when environment favors extreme or unusual traits while selecting against common traits. Short and tall are favored while average is selected against.
Disruptive selection
____: differential mating of males (or females) in a population. Female chooses superior males => increase fitness of offspring; they invest greater energy so they maximize ____. Males increase fitness of offspring by maximizing ____.
Male competition: leads to fights; mating opportunities awarded to strongest male, favors traits like musculature,
horns, large stature, etc.
Female choice: leads to traits/behaviors in males that are favorable to female, favors traits like colorful plumage or elaborate mating behavior. Result often leads to ____ (differences in appearance of males and females) => becomes a form of ____.
sexual selection quality quantity sexual dimorphism disruptive selection
Artificial selection: a form of ____ carried out by humans when they breed favorable traits (not natural selection).
directional selection
SOURCE OF VARIATION
Diploidy: presence of two copies of each chromosome. In heterozygous conditions, ____ is stored for later generations => more variations is maintained in gene pool.
recessive allele
SOURCE OF VARIATION
Outbreeding: mating with ____ partners => mixing different alleles => new allele combinations.
unrelated
SOURCE OF VARIATION
Balanced polymorphism: maintenance of different ____ in population (one is usually best and increased in allele
frequency). However, polymorphisms (coexistence or ____) can exist and be maintained:
a. Heterozygote advantage: heterozygous condition bears ____ than either homozygous conditions. Sickle cell (AA, AS, SS). AS is 14% in Africa because it has ____.
b. Hybrid vigor (____): superior quality of offspring resulting from crosses between ____ strains
of plants => hybrid superior quality results from reduction of loci with ____ conditions and increase in ____.
c. Frequency-dependent selection (minority advantage): least common phenotypes have a selective advantage. Common phenotypes are selected against. Rare will ____ and will be selected against and repeat. Predators (search image of common phenotypes) => rare escapes; rare eventually becomes common, cycle repeats.
phenotypes
two/more different phenotypes
greater advantage
heterosis
two different inbred
deletion of recessive homozygous conditions
heterozygous advantage
increase in frequency
SOURCE OF VARIATION
____ – variation w/out selective value (e.g. ____ in humans)
neutral variation
fingerprints
SOURCE OF VARIATION
Geographic variation – variation of a species dependent on ____ or ____. A graded variation of a phenotype due to this is known as a ____; variation from north/south environments is a north-south cline
climate
geographic conditions
cline
Causes of Changes in Allele Frequencies:
- Natural selection: increase/decrease of allele frequencies due to ____.
- Gene flow: introduction/removal of alleles from population when individuals ____ or ____.
- Genetic drift: random increase/decrease of allele by ____. Small population => larger effect.
- ____: allele frequencies in group of migrating individuals are (by chance) not the same as that of their population origin.
- ____: occurs when population undergoes a dramatic decrease in size (natural catastrophe, etc) => vulnerable to genetic drift. - Nonrandom mating: individuals choose mates based upon their ____ (mates choose nearby individuals).
- Inbreeding: individuals mate with relatives.
- Sexual selection: females choose males based on superior traits. - Mutations
environment
leave (emigrate)
enter population
chance
founder effect
bottleneck
particular traits
