Chapter Eight: Evolution Flashcards
What is evolution?
Is the change in genes of a population on earth over time
What is microevolution?
Refers to changes in one gene pool of a population over generations
What is macroevolution?
Refers to speciation, the formation of an entirely new species
Relate individuals and populations to evolution
Individuas can never evolve
A population is the smallest group that can evolve
What is a population
Consists of all the members of one species in one place
What does a fossil record show?
The existence of species that are extinct or have evolved into other species
What age do radioactive dating and half life suggest the earth is
4.6 billion years old
What are the oldest fossils?
Prokaryotes
What are transitional fossils?
Fossils that link older extinct fossils to modern species
What are homologous structures?
Having different functions in different species, but same internal structure; suggesting common ancestry
What are analogous structures?
Same function, but different underlying structures; suggesting adaptation to similar environment, but NOT common ancestry
What are vestigial structures?
Small parts of structures that used to fully exist before. They suggest that anatomy of animals has evolved, such as the appendix which is no longer needed as our diets have changed
What is comparative biochemistry?
Organisms that have a common ancestor have common biochemical pathways
What is comparative embryology?
Closely related organisms go through similar embryonic stages because they have a common ancestor
What are 6 evidences of evolution?
1) fossil record
2) comparative anatomy
3) comparative biochemistry
4) comparative embryology
5) molecular biology
6) biogeography
What process do all aerobic organisms use to respire and what polypeptide do they need for that?
They use ETC
They need cytochrome c
Cytochrome c is present in all aerobic organisms but does differ in between species. What causes this?
Comparison of the amino acid sequence
What does the theory of continental drift state?
250 million years ago countries were locked together as a supercontinent called Pangaea, which separated slowly into 7 different continents
How can study of location be useful to study evolution?
Presence of fossils
What was Lamarks theory?
Individual organisms change in response to their environment and inherit acquired characteristics
Explain in detail the essence of Dawins theory of natural selection (4)
- Populations tend to grow exponentially, to overpopulate and exceed their resources. •Overpopulation results in competition and struggle for existence
- In any population there exists variation and unequal ability of individuals to survive and reproduce
- Survival of the fittest! Only the best-fit survive and get to pass on their traits. This results in evolution, advantageous traits accumulate in a population
What is Dawins degree for fitness?
Measured by the ability of an organism to survive and reproduce in its environment
What was the weakest part of Dawins theory? How is it now explained?
Sources of diversity in a population.
Genetics now explain that (variation from crossover, and random line up on metaphase plate, and mutations)
How did the giraffe “get” it’s long neck?
Ancestral giraffes were all short-necked, although the length did vary between individuals. As population and competition increased, the talkers ones had a better chance of survival. Over time only long-necked ones increased and others were eliminated. NO ANIMALS NECK GREW LONGER, THE AVERAGE LENGTH OF THE NECK IN THE POPULATION INCREASED
How did the giraffe “get” it’s long neck?
Ancestral giraffes were all short-necked, although the length did vary between individuals. As population and competition increased, the talkers ones had a better chance of survival. Over time only long-necked ones increased and others were eliminated. NO ANIMALS NECK GREW LONGER, THE AVERAGE LENGTH OF THE NECK IN THE POPULATION INCREASED
Explain industrial melanism and peppered moths
At first, most were white, only some dark. White moths camouflaged with their environment and Dark’s ones were easy prey. But with industrialization soot polluted the environment and made everything black. This meant dark moths were camouflaged and had the selective advantage. With time, dark ones replaced white ones. NO MOTH CHANGED COLOR, THE FREQUENCY FOR THE DARK ALLELE INCREASED
Relate evolution and drugs such as antibiotics
Antibiotics killed susceptible bacteria and the rest were resistant. THE ANTIBIOTIC DID NOT INDUCE MUTATIONS FOR RESISTANCE. The resistant survivors pass on the traits to make a population resistant
Why is AIDS so hard to cure?
The AIDS virus has the ability to rapidly mutate and evolve and become resistant to drugs. Susceptible viruses become deactivated but the survivors create an entire population of resistant viruses.
Why do some vaccines need to be developed yearly?
The viruses evolve rapidly
The type of natural selection, frequency of inherited traits, depends on __
Which phenotypes of a population are favoured
What is stabilizing selection?
Eliminates the extremes (they just die) and favors more common intermediate forms
What is disruptive or diversifying selection?
Increasing the no. of extreme types at tge expense of intermediate forms
What is balanced polymorphism?
Results from disruptive selection where in the short term 2 or more phenotypes coexist in a population