Bio 2 final Flashcards
______ is a possible explanation for
an observation
Hypothesis
Must be tested to determine its validity
– Is often tested in many different ways
– Allows for predictions to be made
hypothesis
can be changed and refined with new
data
hypothesis
are random alterations in
genetic information
mutations
why is genetic variation essential for evolution to occur?
allows natural selection to increase and decrease frequency of alleles in population
advantageous to a population because it enables some individuals to adapt to the environment while maintaining the survival of the population.
genetic variation
what does genetic variation result from
mutations, genetic recombination during meiosis and sexual recombination in reproduction.
How do mitosis and meiosis differ
meiosis- reproductive cells, results in 4 haploid cells
Mitosis- body cells, results in 2 diploid cells
3 conditions for natural selection to occur
- Variation must exist
- difference in # of offspring surviving
- inheritance
5 processes that can cause evolutionary change
- mutation
- non-random mating
- gene flow
- genetic drift
- natural selection
what is directional selection?
one phenotype is favored over another
what is stabilizing selection?
intermediate phenotype is favored over extreme
what is disruptive selection?
only extreme phenotypes are favored
what species do not have overlapping ranges
allopatric
Sympatric is when species occur ___________ in an area
together
what does a phylogenic tree represent?
evolutionary relationship of organisms, (their lineage)
what derives from a common ancestor
ancestral character
what is a derived trait
trait in present organism but not in ancestor organism “new and improved model”
Are prokaryotes multicellular or unicellular?
unicellular
what do prokaryotes lack?
nucleus, organelles bound by membranes
prokaryotes are divided by what?
binary fission
Are eukaryotes multicellular or unicellular?
multicellular
What do eukaryotes have?
what prokaryotes lack, a nucleus and organelles bound by membranes
what is haplodiplontic lifecycle
gametes are not the direct result of a meiotic division. Diploid sporophyte cells undergo meiosis to produce haploid spores.
what is alternation of generations?
rotation b/w haploid and diploid stages
5 derived traits of land plants
- AOG
- multicellular dependent embryos
- multicellular gametangia
- walled spores produce sporangia
- apical meristems
what are key transitions in animal evolution?
- tissues
- symmetry
- body cavity
- development
tetrapods that have a
terrestrially adapted egg
amniotes
what is the significance to the amniotic egg?
External fertilization does not work on land
what did amniotic egg allow?
allowed reptiles to replace amphibians and become the dominant terrestrial vertebrate
significance of water tight skin
prevent water loss and drying of skin
structure of epithelial tissue
covers outside of body & lines organs within body