1. Adaptations Flashcards
What is an adaptation?
The condition of organisms being well equipped - both by structure and function or behaviour - to live in their environment
Give an example of adaptive radiation.
Darwin’s finches
What is evolution, put simply?
Descent with modification
Darwin lacked a theory of inheritance, so what ideas did he use?
Blending inheritance
Character A from a mother and A’ from a father yield a blended heritable character A’’ in the offspring
What is the modern synthesis/ neo-Darwinism?
The modern synthesis combines the Mendelian theory of heredity and Darwin’s theory of evolution
Mendelian heredity is needed as it conserves genetic variation
What are some theories for adaptation?
Competing browser hypothesis
“Necks-for-Sex” hypothesis
Vigilance hypothesis
Describe the competing browser hypothesis.
Trying to reach higher branches, neck gets longer over time to reach higher
(Giraffes)
Describe the “Necks-for-Sex” hypothesis.
Fighting to impress females
Giraffes
Describe the vigilance hypothesis.
Can look further, detect predators
Giraffes
What is a gene?
A sequence of nucleotides that codes for an RNA or a protein product
The unit of heredity, which segregates and recombines with appreciable frequency
Due to mutations, you see variation in a population
How does the rate of molecular evolution vary over time?
It works at an almost constant rate
What does fitness of a genotype give a measure of?
Gives a measure of its relative ability to leave offspring in the next generation
Why is fitness a useful concept?
It lumps survival, mate-finding and reproduction into one measure for natural selection
What does sexual selection act upon?
Acts on an animal’s ability to obtain and copulate with a mate
Often powerful enough to produce adaptations that are harmful to the individual’s survival
What is Darwin’s gradualist requirement?
Evolution goes in small steps
So you need to be able to show intermediate steps between one form and another
