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Worksheets12 ATAR HB - Gene Pools
Total questions: 37
Worksheet time: 51mins
Define evolution in genetic terms.
any change in the frequency of alleles in populations of organisms from generation to generation.
any change in the frequency of alleles in an individual organism over it's lifespan.
any change in the frequency of alleles in communities of organisms from generation to generation.
any change in the frequency of alleles in an ecoystem of organisms from generation to generation.
The physical appearance, physiological functions, and behavioral characteristics (instinctual) of an organism based on traits
Genotype
Phenotype
Meiosis
Genetics
Why do we say that natural selection never acts directly on genes?
Because natural selection is in dire need of acting classes.
Because natural selection “selects” an entire organism—not a single gene or group of genes—to either survive and reproduce or die without reproducing.
Because specific forms of a gene, called alleles, may vary from individual to individual. Natural selections "selects" form these groups of genes.
Because members of a population interbreed with one another, they share a common group of genes called a gene pool.
the total genetic information available in a population
population genetics
microevolution
gene pool
allele frequency
determined by dividing the number of a certain allele by the total number of alleles of all types in the population
population genetics
microevolution
gene pool
allele frequency
equal to the number of individuals with a particular phenotype divided by the total number of individuals in the population
phenotype frequency
hardy-weinberg genetic equilibrium
gene pool
allele frequency
Retinitis pigmentosa (RP) is an autosomal recessive trait that results in progressive blindness in humans.
On the island of Tristan da Cunha in the Atlantic Ocean, the frequency of the allele causing RP is four times greater in its population of a few hundred individuals than in the original British population from which it was colonised in the early 1800s. No natural disasters have occurred on the island since it was colonised.
The process that is most likely responsible for this observation related to allele frequency is
Founder effect
Genetic bottleneck
Genetic drift
Natural selection
Lucilia cuprina, the sheep blowfly, lays its eggs in wounds and the wet fleece of sheep. The larvae hatch and burrow into the sheep's skin, causing distress, reduced wool production and sometimes death. Particular chemicals were used in the past to control the L. cuprina but these became less effective as sheep blowfly developed a resistance to the chemicals.
The cause of the increased resistance to the chemicals was most likely due to
farmers successively reducing the levels of insecticide applied to sheep.
the insecticide producing a change in a gene which enhanced the survival of the blowfly.
a chance mutation in a blowfly gene conferring a survival advantage in the chemical environment
the insecticide producing a change in phenotype which enhanced reproduction of the blowfly.
Lactase is an enzyme in humans which breaks down lactose, one of the sugars in milk. Milk is a safe and nutritious food which is readily available year-round. Although most adults around the world lose the ability to produce lactase as they mature, more than 90% of Europeans have a lactase-producing allele which remains active into adulthood.
Scientists analysed DNA in bone samples from a number of Neolithic Europeans (dated between 5840 BC and 5000 BC) and found that none of them had the adult lactase allele.
The most likely explanation for this data is that
the adult lactase-producing allele which remains active into adulthood arose millions of years ago in ancestors of modern humans
possession of the adult lactase-producing allele which remains active into adulthood confers a significant evolutionary advantage
the adult lactase-producing allele which remains active into adulthood did not arise in Europe
modern Europeans are not descended from the Neolithic Europeans tested.
The founder effect and bottleneck are examples of
gene flow
speciation
genetic drift.
selection pressures.
Early in 2012, biologists announced the discovery of a new lizard species.
To claim that the lizards belong to a new species, the biologists must show that the lizards
look different from one another
.look different from known species
have similar genetic sequences to known species
do not produce fertile offspring with members of known species.
Australian Eucalyptus trees characteristically have two types of leaves, a juvenile (young) form and an adult form. The juvenile leaves are held horizontally and are relatively large and broad, while the adult leaves hang vertically and are long and narrow. Typical juvenile and adult leaves are shown.
A selection pressure which is likely to have had the greatest influence on the evolution of the juvenile leaf shape and position would be
competition for light
unpredictable rainfall
browsing by herbivores
.high ambient temperatures.
A scientist took a small population of 10 flowering plants and conducted an experiment to examine the change in allele frequencies over three generations. The plants were grown in identical conditions, in a controlled environment.
Within the flowering plants the presence of the R allele allows red flowers to be produced, while white flowers can only be produced when the rr genotype is present.
Genotype numbers
Generation 1 Generation 2 Generation 3
RR 6 3 0
Rr 2 3 4
rr 2 4 6
Total alleles 20 20 20
The most likely reason for the population of flowering plants having more rr genotypes and white-flowered phenotypes after only three generations is
genetic drift
.natural selection
divergent evolution
.convergent evolution.
Since the introduction of the poisonous cane toad to Australia in 1935, there has been an increase in the ratio of body length to head size in two species of snakes, the Red-bellied Black Snake and the Green Tree Snake.
A smaller headed snake cannot consume a large prey item, and so cannot swallow a large cane toad that has sufficient toxin to kill the snake.
The rapid evolution of body dimensions in the Red-bellied Black Snake and the Green Tree Snake most likely came about because
cane toad toxin reduced the head size of the snakes
even small cane toads contain enough toxin to kill a long-bodied snake
smaller headed snakes are better at catching cane toads than large headed snakes
larger headed snakes were killed by the levels of toxin ingested when they ate a large cane toad.
Consider the diagram below that models changes in allele frequencies for one trait in a population over two generations. The original population is shown on the left.
If the diagram above models the founder effect, then event X is
migration
natural disaster
random mating
random assortment of alleles
In populations
genetic drift will have less effect in a large population compared to a small population
bottlenecks enable a population to become better equipped for future changes in the environment
some organisms develop mutations in order to better suit them to their environment compared to other members of the population
allele frequencies remain constant if the number of individuals leaving the population equals the number of individuals entering it.
The type of genetic drift that follows the colonization of a new habitat by a small group of individuals is called
Natural Selection
the founder effect
directional selection
the bottleneck effect
Which of the following is an example of natural selection?
Bald Eagles are hunted until near extinction, population recovers.
Small group of iguanas floats to an island, starts a new population.
Red fox pups are more likely to survive in a snowy environment if they are born white.
Farmer chooses seeds from largest apples to plant next year. This results in larger apples from year to year.
Bats are common in Texas, especially in rocky regions. Bats with longer hang claws have demonstrated higher fitness because of their ability to cling to rock while resting. This adaptation is becoming more frequent in the population. What mechanism of evolution is this?
Natural Selection
Non-random mating
Gene Flow
Genetic Drift
When individuals choose traits possessed by the opposite sex it is called…
Mutation
Gene Flow
Genetic Drift
Sexual Selection
Which of the following is an example of the bottleneck effect?
Cheetah populations reach their lowest levels with reduced diversity and as they rebound are so genetically similar they appear to be inbred.
Affected individuals with blue skin can trace their ancestry back to one of the first settlers in the region.
The environment of a fox population changes and over time foxes who are white survive and pass on their genes to their offspring.
Humans choose two dogs they like the characteristics of and breed them together.
Which of the following is an example of the founder effect?
Humans choose two dogs they like the characteristics of and breed them together.
Affected individuals with blue skin can trace their ancestry back to one of the first settlers in the region.
The environment of a fox population changes and over time foxes who are white survive and pass on their genes to their offspring.
Cheetah populations reach their lowest levels with reduced diversity and as they rebound are so genetically similar they appear to be inbred.
