Flashcards in Bio Unit Test 2 Deck (117)
What is evolution?
The result of changes over time. Natural and Necessary.
Give an example of evolutionary mutations.
Bacteria becoming resistant.
What is a mutation?
Spontaneous, natural changing of the structure of a gene
What are the basis of genetic variation?
The more complex the organism...
...the less mutations occur.
What are the 3 types of mutation?
Neutral, harmful, beneficial.
What is neutral mutation?
One that does not result in advantage or disadvantage.
Give an example of a neutral mutation.
CAA, CAG are both codes for the amino acid called Glutamine.
What is harmful mutation?
Any mutation that makes the individual less successful. It will be selected against and will not accumulate.
Give an example of harmful mutation.
A mutation can disrupt a cell's life cycle, so that it divides uncontrollably. This is cancer.
What is beneficial mutation?
Any mutation that increases the reproductive success of an organism. It will be selected for, and will accumulate.
Give an example of beneficial mutation.
A mutation that slightly increases the size and robustness of a bird's beak may allow it to expand its food sources.
Talk about sickle cells.
A certain mutation results in the cells killing each other (sickle-cell anemia). This mutation however does protect the individual from malaria. In this way it is beneficial and more prevalent in places where there are malaria epidemics.
Talk about bacterial resistance.
The bacteria mutate and become resistant to antibiotics. This is beneficial to the bacteria but harmful to the hosts.
What determines if a mutation is good or bad?
The situation. For example: the more human pigment someone has the more protected they are from UV absorption and vitamin D.
When does selective breeding occur?
When humans interfere with natural selection to help breed chosen characteristics that are beneficial to us.
What is selective breeding common for?
Plants (corn) and animals (dogs).
How long does selective breeding take?
A long time, it takes several generations.
What are some ways we selectively breed dogs?
Changing their size and Altering them to better sniff out vermin, hunt birds.
What is artificial selection?
Directed breeding in which individuals that exhibit a particular trait are chosen as parents of the next generation.
What does the process of artificial selection allow us to produce?
New organisms with specific traits.
What was the earliest domesticated animal?
Wolves, modern dogs descended from wolves.
What is the benefit of artificial selection?
It can create a situation with more variability than would occur in nature.
Give an example of a scenario where less variability would occur than in nature because of artificial selection.
Several types of carrots exist but we eat the orange ones because they are crispy and sweet.
What could favoured alleles (traits) be linked to?
A detrimental trait.
What is an allele?
What are the limits of artificial selection?
1. Having to work with existing traits only.
2.Harmful mutations can be passed on along with desired ones.
3. If the species becomes too alike, they can be all wiped out by the same disease.
Where does some of the most compelling evidence for evolution come from?
What is biogeography?
The study of geographic distribution of organisms based on both living species and fossils.