Biodiversity and Evolution Flashcards
what is the narrow, more formal definition of evolution
the genetic changes in a population over generations
what is the broad definition of evolution?
change in populations over time
what do genetic changes lead to
modifications in appearance, function or behavior of organisms
what is one of the best supported theories in science
theory of evolution
what is the foundation for modern biology
evolutionary theory
why is evolutionary theory the foundation for modern biology
Knowing how organisms adapt and respond to environments over time is vital for understanding history of life
what does biological evolution result from
RANDOM genetic changes
natural selection
Process where traits that enhance survival and reproduction pass on more frequently to future generations than those that don’t
what can natural selection alter
the genetic makeup of an ENTIRE population
what is the mechanism for evolution
natural selection
what is natural selection based on
unique characteristics seen in the SAME species
does natural selection target a single species or multiple at a time
single species
is natural selection universal for ALL animals
NO - some traits that are beneficial for one species might be disadvantageous for other species
what do species evolve into over time due to natural selection
posses characteristics that lead to better and better success in their given environment
adaptive trait aka adaption
a trait that promotes success
maladaptive trait
a trait that reduces success
what were three observations found by Darwin and Wallace that contributed to natural selection theory
- Organisms produce more offspring than can survive and some are more likely to survive and reproduce than others
- this also insights competition for food, mates, space… - Organisms face a constant struggle to gain enough resources to survive and reproduce
- offspring might inherit the characteristics that give individuals an advantage in surviving and reproducing, and the traits woudl then become more prevalent in the population for future generations
what must a trait be for natural selection
heritable (genes in the DNA code for the trait and its passed along generations)
sources of genetic variation in populations
- mutations (changes in nucleotides in DNA)
- sexual reproduction (recombination)
three ways natural selection can act on genetic variation
- directional selection
- stabilizing selection
- disruptive selection
directional selection
selection that drives a feature/trait in one extreme or the other (not the intermediate)
stabilizing selection
selection that produces the intermediate trait
disruptive selection
selection were traits diverge from their starting condition in BOTH extremes
Stabilizing Selection
Directional Selection
Disruptive selection
Selective pressures
an evolutionary force that causes a particular phenotype to be more favorable in certain environmental conditions.
are all selective pressures the same for each environment
NO
divergent evolution vs convergent evolution
divergent evolution ; two populations of the SAME species, which are geographically separated or reproductively isolated, evolve different traits over time because of adaptation to selective pressures from different environments or habitats.
convergent evolution ; Completely unrelated species develop similar traits because of adaption to selective pressure that are similar in their respective environments