E1 - Intro to Evolution Flashcards
Who is Leclerc de Buffon and what did he belivie?
-He examined animal body structure and function and was puzzled by anatomical features that seemed to serve no purpose
-He believed that the species had been created in a more perfect form but changed over time
What did carl linneaus suggest?
that life changed over time
What did Erasmus Darwin suggest?
that all life might have evolved from a single original source
Chevalier de Lamarck proposed a mechanism for the evolution of species through 2 distinct principals:
Use and Disuse
Inheritance of Acquired Characteristics:
Use and Disuse
Structures that an individual used, became larger and stronger and structures that were not used, got smaller and weaker
Inheritance of Acquired Characteristics:
Individuals could pass characteristics onto their offspring that they had acquired over their lifetime
what was the problems with Lamarcks ideas
we know that traits can change over an individual’s lifetime, but that does not change their DNA or how their traits are passed on
For example, a giraffe cannot “stretch” its neck over its life and pass on the trait of a longer neck to its offspring
what book held convincing evidence that species have evolved
and also proposed a theory of how species evolved
Darwin’s On the Origin of Species
why did Darwin publish his book
received a letter from a young biologist named Alfred Russell Wallace outlining almost an identical theory Darwin became more anxious to publish
how did Darwin describe natural selection
described natural selection as a way in which the environment favours the reproductive success of certain individuals over others
- Evolution was simply the result of natural selection occurring over many generations
what was Darwins theories?
All healthy populations produce far more offspring than can survive
All individuals exhibited heritable variability
What did Darwin conclude from his theories
Some individuals will have better chance of success than others
Their traits are therefore more likely to be passed onto the next generation
Who coined the term “Survival of the Fittest” to describe process of evolution
Herbert Spencer
Why is “Survival of the Fittest” not true?
Being “fit” is not important, being more likely to have reproductive success is what is important!
-its the organism that is most adaptable to change that will survive
Evolution
Change in the gene pool over time from generaqtion to generation by such processes as mutation, natural selection and genetic drift
gene pool
The set of all genes or gentic information, in any population
ex: red hair and non-red head is 50%
-like a card deck that is reshuffled
-deck remains the same through generations, i.e 50% red
-if the frequency varies the evolution has occured
evolution in simple terms
change in the gene pool over time
5 fingers of evolution- little finger
- if population shrinks then chance can take over
ex, if a couple people survive a epidemic than their genes will represent the new gene pool
5 fingers of evolution- ring finger
reminder: mating (ring on ring finger)
- if indivduals choose a mate based on apperence or location the frequency may change
5 fingers of evolution- middle finger
reminder; “M” in middle finger should remmind you of mutatuons
- if new gene is added through mutation then it affects frequency
5 fingers of evolution- pointer finger
reminder: movment
-If a new indivdual flow into an area the frquency will change or even if they leave
- this is called gene flow
gene flow simplified
If a new indivdual flow into an area the frquency will change or even if they leave
WHAT DOES NOT LEAD TO ADAPTATION
- however, small populations, non-random mating, mutations and gene flow DO NOT LEAD TO ADAPTATION
what is the only process thay creates organisms better adapted to their local enviroments
natural selection
