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Thomas Malthus argued that population growth tends to be exponential
while growth of the population's food base tends to be geometric.
_______________proposed that species evolve due to natural selection.
Wallace & Darwin
The total number of species living on earth today has been estimated to be as high as
The evolutionary history of a group in organisms, which is often illustrated in tree-like form to depict relationships among members of
When biologists do descriptive science, they must use the scientific method.
Your study partner in BIOL1200 looked over the results of the Echinacea experiment and concluded that although Echinacea treatment does not prevent common colds, it does shorten the duration of a cold, following infection. Do you agree with his conclusion?
The view that species do not change over time is associated with which species concept?
typological species concept
A vestigial trait represents a character that
changed substantially to the point that it no longer performs the function for which it originally evolved
Structural homologies refer to morphological characters that arose from a common ancestor, have the same general structure, but can have very different functional roles.
One line of support for species descending from a common ancestor is the
observation that similar, closely related species often occur in the
same geographic region.
The brown chipmunk’s color is
coded by a single gene characterized by a single allele that produces a
brown pigment. Volcanic ash covers the landscape after a recent
eruption, such that the ground, where these chipmunks live, is changed
from brown soil to light gray ash. What is the most likely outcome for
this population of chipmunks?
most members of the population will probably be consumed by predators
The algebraic symbol 2pq in Hardy's formula represents
the frequency of heterozygous offspring in the next generation
The evolution of deeper beak size in the medium ground finch population on Daphne Major is the result of
Selection for those individuals in the population with larger beaks
Which explanation in question 3 is consistent with a Lamarckian view of beak evolution?
Enlarged jaw muscles due to continual use in cracking larger seeds
Term used to describe a heritable trait that increases an individual's fitness in certain environments.
Which set of symbols is consistent with a homozygous genotype for a gene that exhibits codominance?
A population's allelic frequencies of A and a are 0.4 and 0.6, respectively. After one round of random mating, the frequency of heterozygotes in the next generation will be ____.
Natural selection acts on____
A species of wildflower has flower color determined by a single locus, with the following phenotypes (genotypes): red (CR CR), white (CW CW), and pink (CRCW).
A population consists of 64% red-flowered plants, 4% white-flowered
plants, and 32% pink-flowered plants. What is the frequency for allele
Which of Darwin's four postulates best illustrate how he was influenced by Thoma Malthus's An Essay on the Principles of Population?
More offspring are produced per generation than can survive
What are the assumptions of H-W?
There is no
- 1Nonrandom mating (with respect to the gene in
- question) 2Natural selection 3Mutation 4Gene flow 5Genetic drift
the evolutionary history of organisms
variety of life on earth and the natural patterns this variation creates.
Biodiversity is measured by
the number of species
- Patten in nature vs process responsible for the
Typotypic species concept
- Every species was a perfect type and therefore
- unchanging and independent of one another.
Great chain of being
- Although species are “fixed,” they had an organization
- sequence, from small and simple to large and complex.
- Populations grow geometrically but their food
- supply grows arithmetically, species grow faster than food source.
Who had views on the process of evolution that were identical to Darwin’s?
Alfred Russel Wallace
- A structure that served a purpose in one species but
- changes to serve another purposeLobed- fins to limbs in evolving species
What are vestigial traits? Give some examples.
- Traits that are left behind or are shadows of their former
- of monkeys to coccyx (tailbone) of humans.
- similarities between species that are the result
- of common ancestry, either relatively recently or in the distant past
- Chicken human and cat embryos are very similar
- in appearance in early stages, they contain gill pouches and tails
- similar bone structure in the limbs of several
- animals, humans, horse, bird, bat
- change in allele frequencies in a population
- over time.
- a heritable trait that increases fitness of an
- individual in a particular environment over individuals lacking the trait.
- French naturalist who documented fossil animals,
- concluding that some species had gone extinct.
- British geologist. The earth is complex, and it has
- taken vast amounts time to form mountains ect, RESULT- people began thinking that the earth was
- much older than they previously had
- Proposed species change over time through the
- inheritance of traits acquired from use or disuse.
What is meant by the expression “internal consistency”
with regard to evolution?
- All observations are consistent with the idea that
- one species evolved from another, and observations may even support one another
What are Darwin’s four postulates?
- 1)Individuals in a population vary in traits
- 2)Some trait differences are heritable
- 3)More offspring produced over generation than can
- 4)Individuals with heritable traits that enhance
- survival tend to produce more offspring, also bearing those traits.
natural vs. artificial selection
- In artificial, we are the agents of change, in
- natural, the environment is the agent of change
How many generations of random mating are required to
reach H-W equilibrium?
What happens to allelic and genotypic frequencies once
a population is in H-W equilibrium?
They stay the same
- A change in allele frequencies in a population due to
- chance (unlike natural selection, it is undirected and random)
What is genetic drift? What is its role with
regard to fitness?
- Random loss and/or fixation of alleles.
- In the case of allele X and Y, if allele X is lost, Y
- becomes fit by default
- Small populations are prone to drift
Genetic bottleneck (type of genetic drift)
- high mortality strikes individuals at random,
Founder Effect (type of genetic drift)
Small subset leaves a population. When small group settles, their allelic frequencies differ from the original population
What is sexual selection? Who first recognized/proposed it?
Selection favoring traits that increase an individuals’s ability to obtain or preferentially choose mates. Charles Darwin
List the fundamental asymmetries of sex.
- Females- Invest substantially in egg production
- • Produce fewer gametes over
- lifetime than males
- • Can invest substantially in rearing young
- • Produce fewer offspring over lifetime than male
- Invest very little in sperm production
- • Produce far more gametes over lifetime than females
- • Less likely to invest time and energy in rearing young
- • Potentially produce many more offspring than females
intra- vs. inter sexual selection
- Intra-Competition (often male male) for mates
- Inter-Individuals choose their mates (often female choice)
Why are males often brightly colored?
So females will be more likely to choose them, as more colorful males may indicate healthier
Is there empirical evidence for the good genes hypothesis?
Yes, The long call of frogs experiment in which the eggs of the female were combined with the sperm of the males. The long called frogs offspring were superior in all ways to the other
What is male-male competition? Does it
represent intra- or intersexual selection?
Males competing for females. Intrasexual
What are the consequences of sexual selection?
What is the connection between sexual
selection and sexual dimorphism?
Dimorphism-antlers on a deer, red male cardinals and plain females. Different male and female appearences. These are developed through sexual selection
In what ways does mutation differ from other forces
responsible for evolution?
It is the source of new variation
What is the typical outcome of gene flow between
In other words how are the source and recipient
Causes allele frequencies in the two population to become more similar with lots gene flow & no NS, allele frequencies can become identical