origin of species Flashcards
The Origin of Species
Darwin published the Origin of Species was published in ___1869_______. This book explained that species had evolved and a theory on how they evolve.
Darwin took so long to publish his findings because he knew the theory would be controversial and wanted as much evidence as possible.
___Alfred ___Wallace_______________________also had a theory of evolution, very similar to Darwin’s. This prompted Darwin to come forward with his theory.
Natural Selection
the way in which nature favours the reproductive success of some individuals within a population over others. Evolution simply results from natural selection occurring over many generations.
5 Key Observations
In each generation, populations produce more offspring than there are adults
Populations do not continue to grow in size.
Food & many other resources are limited.
Individuals within all populations vary.
Many variations are heritable.
Inferences
Individuals within a population compete for resources
Some individuals will inherit characteristics that give them a better chance of surviving & reproducing
Theory of Natural Selection
Over time the population changes as advantageous heritable characteristics become more common generation after generation
3 types of Adaptations
Adaptations can take many forms: a behaviour that allows better evasion of predators, an anatomical feature that allows the organism to access valuable resources etc.
Mimicry
Toxins
Echolocation
Variation
Members of a population have slight differences among them. This variation must be heritable.
Competition
Populations tend to create more progeny than can survive. Not all progeny survive due to competition for food, nesting sites, mates, or other resources.
Survival of the fittest
Better adapted individuals survive and reproduce (pass genes to their offspring)
Gradual
over many generations, the more advantageous traits become common in the population.
modern evolutionary synthesis
All of the information we have gathered from modern science and Darwin’s theory
Radiometric dating
Paleontologists are able to use radioisotopes to obtain precise estimates of the ages of rocks. Radioisotopes- are atoms with an unstable nucleus that is capable of undergoing radioactive decay.
