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Understanding Evolutionary Biology
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Understanding Evolutionary Biology
Understanding Evolutionary Biology
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1
Question
What is Evolution in biology?
Answer
In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection. It involves the process of biological change over time.
2
Question
What is the theory of evolution based on?
Answer
The theory of evolution is based on the idea that all species are related and gradually change over time.
3
Question
What does it indicate when DNA and genes in different species look very similar?
Answer
When DNA and genes in different species look very similar, this is usually taken as evidence of them sharing ancestors.
4
Question
What is an example of shared DNA between species?
Answer
Humans and the fruit fly Drosophila melanogaster share much of their DNA; 75 of the genes that cause diseases in humans are also found in the fruit fly.
5
Question
What happens to DNA over time?
Answer
DNA accumulates changes over time, some of which can be beneficial and provide a selective advantage for an organism, while others may be harmful.
6
Question
What are conserved genes?
Answer
Some genes do not change much and are said to be conserved.
7
Question
What did paleontologists perceive about evolution in fossil records?
Answer
Paleontologists perceived in the fossil records evolution that could drive species toward extinction or orthogenetic straight line theories.
8
Question
What is an example of an extinct species due to evolution?
Answer
The extinct Irish deer Megaceros giganteus became extinct because it could not stop evolving ever-larger and more cumbersome antlers.
9
Question
What is convergent evolution?
Answer
Convergent evolution occurs when the same adaptations evolve independently under similar selection pressures.
10
Question
Provide an example of convergent evolution.
Answer
Flying insects, birds, and bats have all evolved the ability to fly, but independently of each other.
11
Question
What is co-evolution?
Answer
Co-evolution occurs when two species or groups of species have evolved alongside each other, where one adapts to changes in the other.
12
Question
Give an example of co-evolution.
Answer
Flowering plants and pollinating insects such as bees demonstrate co-evolution.
13
Question
What is adaptive radiation?
Answer
Adaptive radiation occurs when a species splits into a number of new forms when a change in the environment makes new resources available or creates new environmental challenges.
14
Question
What is a gene pool?
Answer
The gene pool is the collection of all the genes and the various alternate or allelic forms of those genes within a population.
15
Question
What are the two major types of evolutionary mechanisms?
Answer
The two major types of evolutionary mechanisms are those that act to increase genetic variation and mechanisms that operate to decrease genetic variation.
16
Question
Name mechanisms that increase genetic variation.
Answer
Mechanisms that increase genetic variation include mutation, recombination, and gene flow.
17
Question
Name mechanisms that decrease genetic variation.
Answer
Mechanisms that decrease genetic variation include genetic drift and natural selection.
18
Question
What are the types of mutations?
Answer
The types of mutations include chromosomal mutations, point mutations, frame shifts, and breakdowns in DNA repair mechanisms.
19
Question
What are point mutations?
Answer
Point mutations may be nonsense mutations (leading to early termination of protein synthesis), missense mutations (resulting in a substitution of one amino acid for another), or silent mutations (causing no detectable change).
20
Question
What is a frameshift mutation?
Answer
A frameshift mutation involves the insertion or deletion of a nucleotide in which the number of deleted base pairs is not divisible by three, disrupting the reading frame.
21
Question
What is DNA repair?
Answer
DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome.
22
Question
List the major DNA repair pathways.
Answer
The major DNA repair pathways include base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), homologous recombination (HR), and non-homologous end joining (NHEJ).
23
Question
How does mutation generate variation?
Answer
Mutation generates variation whenever a mistake occurs in the DNA in the heritable cells of an organism.
24
Question
What is the standing genetic variation?
Answer
The variation created in a population through the random process of mutation is called standing genetic variation, which must be present for evolution to occur.
25
Question
What is the impact of mutation rates on evolution?
Answer
Mutation rates are low for most genes, making mutation alone not significantly impactful on evolution; however, when combined with other mechanisms, meaningful changes in allele frequencies can result.
26
Question
What does recombination involve?
Answer
Recombination involves the re-assortment of genes through new chromosome combinations and occurs via an exchange of DNA between homologous chromosomes during meiosis.
27
Question
What is gene flow?
Answer
Gene flow is the flow of alleles in and out of a population resulting from the migration of individuals or gametes.
28
Question
How does gene flow impact allele frequencies?
Answer
Evolution by gene flow migration makes two different populations more similar to each other by introducing different allele frequencies.
29
Question
What is genetic drift?
Answer
Genetic drift results from changes in the numbers of different forms of a gene (allelic frequency) that result from sexual reproduction.
30
Question
How does genetic drift affect populations?
Answer
Genetic drift can cause changes in populations by chance alone, resulting in some alleles being over-represented while others decline in frequency, regardless of their phenotypic suitability.