Evolution (2) Flashcards
Published On the Origin of Species…
Charles Darwin
Father of Evolution
charles darwin
Darwin’s thoughts on Natural Selection
Darwin’s thoughts on Natural Selection explained a lot about evolution, but he didn’t explain the mechanism by which traits change over time.
Theories of Evolution
Overproduction
Competition
Variations and Adaptations
Natural Selection
Speciation
Most species produce far more offspring than can survive. Those that die are considered ‘weak’
overproduction
Since living space and food are limited (limited resources), offspring must compete for resources
Competition
characteristics of the individuals in any species are not exactly alike
Variations & Adaptations
Organisms with variations that make them better adapted to their environment survive and reproduce
passing on favorable traits to offspring
natural selection
Over many generations, favorable adaptations gradually accumulate in the species and bad traits disappear.
speciation
sources of genetic variation
mutation
genetic recombination
migration
genetic drift
Random changes in the genetic makeup of an organism
mutations
Gametes uniting during fertilization
genetic recombination
New traits being brought into / taking out traits out of a population
migration
has greatest effect on small populations
migration
Affects small populations
changes in the gene pool due to storms, a catastrophe, etc.
genetic drift
tends to decrease gene pool
genetic drift
Focuses on population than individual
The Modern Theory of Evolution
study of changes in genetic makeup of populations.
population genetics
how often a particular allele (trait) is found within a population.
frequencies
total of all alleles present in a population.
Mathematically explained by Hardy Weinberg.
gene pool
peppered moth’s signifance
shows how environmental factors can drive natural selection
adaptations
structural
physiological
Involves parts of body (wings for flying, fins for swimming).
structural adaptations
Involves metabolism of organism (poison venom).
Other adaptations are mating, behavioral, hibernation, etc.
physiological adaptations
The emergence of many species from a common ancestor that was introduced to new environment
adaptive radiation
Natural selection causes non- related species to resemble one another
wings in birds, bats, insects
echolocation in dolphins & bats
thorns in cacti & roses
shark & dolphin bodies
vertebrate & cephalopod eyes
convergent evolution
Two+ species evolve in response to each other through competitive or cooperative adaptations
predator-prey interactions
host-parasite interactions
plants & fungi / bacteria
flowers and their pollinators.
coevolution
