BIOL3044 Lecture Notes - Lecture 1: Stabilizing Selection, Genetic Correlation, Genetic Variation

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indigobat594

13 Nov 2021

School

Dalhousie University

Department

Biology

Course

BIOL3044

Professor

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Document Summary

Phenotypic plasticity: the idea is related to the idea of organisms being able to maintain moderately high fitness in a range of different environments because some aspects of the phenotype can respond to changes in the environment. Definition: the condition wherein a genotype produces different phenotypes in different (macro-) environments: there will be some variation that is not attributable to genotype. Phenotypic plasticity is systematic: ex. an organism consistently produces a longer tail in colder environment and shorter tail in warmer environments. If these were developed during the developmental period of the organisms" life, it might remain constant throughout adulthood. It is an aquatic species that grows in freshwater ponds, streambanks. It"s a typical look of aquatic plants: as it grows and summer approaches, the leaves emerge from the top of the water. Later on, in the season when predators are fairly rare again, the daphnia revert back to their shorter, rounded helmet form.

Related Questions

1. If an individual has a genotype of Bb, what types of gametes (sperm/egg) could they produce?
A) B
B) b
C) B or b
D) Bb, BB, bb
E) Bb

2. Which of the following statements is true about phenotypic plasticity, i.e., phenotype variation that is the result of genotype by environment interactions?
A. Phenotypic plasticity is only favored when the parental environment is a good predictor of the offspring environment
B. Since the trait expression of a genotype varies across environments, it cannot respond to selection
C. A variable environment is required for phenotypic plasticity to be selected for
D. A single trait can only ever be plastic or non-plastic within a species
E. Phenotypic plasticity can only occur within a single generation, never across generations

3. With large numbers of genes contributing to variation for a phenotypic trait (e.g. height in humans), the population approaches what kind of distribution for that trait?
A. Mendelian
B. Exponential
C. Binomial
D. Normal
E. Continuous

4. A classic example of phenotypic plasticity is caste determination in social insects. Whether a female ant becomes a worker, soldier, or queen is determined by the food she is fed. Would you say this this an example of G, E, or GxE?

5. In an infinite population, the frequency of the A allele is 0.3 and the frequency of the a allele is 0.7. What is the frequency of heterozygotes?
A. .10
B. .21
C. .30
D. .42
E. .70

6. Blue eyes are a recessive trait caused by an autosomal allele. If there are 180 people with blue eyes in a population of 500 people, what is the frequency of the brown-eye allele? (Assume HWE)
A. .36
B. .40
C. .50
D. .60
E. .64

7. Imagine flower color in diploid roses is determined by a single gene with two alleles, white and red, which are co-dominant so that heterozygotes are pink. Frank is colorblind and can only discriminate between white and colored roses, and knows that his population has 18 white roses and 182 non-white roses. How many of Frankâs roses are pink? (Assume HWE.)
A. 18
B. 21
C. 42
D. 84
âE. 100

8. Imagine flower color in diploid roses is determined by a single gene with two alleles, white and red, which are co-dominant. If Eva's population has 250 white roses, 500 pink roses, and 250 red roses, what is true about this population?

A. It is not in Hardy-Weinberg equilibrium
B. It is under balancing selection
C. It is connected to another population by migration
D. It is in Hardy-Weinberg equilibrium
ââE. White is a recessive lethal

9. 9% of a population is unable to taste the compound PTC, which is a recessive trait. Assuming HWE, if two carriers of the non-tasting allele had a baby what is the probability that it would be unable to taste PTC?
A. 0.09
B. 0.25
C. 0.30
D. 0.50
E. 0.70

10. (Adapted from: Christensen, A. C. (2000). Cats as an aid to teaching genetics. Genetics, 155(3), 999-1004.) ss cats have no white fur, Ss cats generally have <50% white fur, and SS cats generally have >50% white fur (cats who are 100% white are scored as dominant white and can't be scored for piebald spotting). The S allele is incompletely dominant, but variably expressed, so there is a more-or-less continuous gradient of white pigmentation in populations. You and your friends score all non-white cats up for adoption: http://www.adoptapet.com/cat-adoption/search/50/miles/48824 and find there are 160 with >50% white fur, 350 with <50% white fur, and 490 with no white fur. Which of the following statements is definitely true:

A. The population is in Hardy-Weinberg equilibrium
B. The population is not in Hardy-Weinberg equilibrium
C. There is selection acting on the population
D. It is impossible to know if the population is in Hardy-Weinberg equilibrium
E. Fur color is not a heritable trait and therefore cannot evolve

tanbadger837

(a) Discuss ways in which phenotypic variation occurs withinpopulations. (b) Explain how phenotypic variation aids in thesurvival of the fit.

Write your response below.

a) phenotypes can be caused by

genetic variation
environmental factors
Both.

Genetic variation cause phenotypic change. when two geneticallydifferent parents mate then there are chances to get phenotypicvariations. Like a mule is crossbreed between a horse and a donkey.while environmental factors are things in an organism'ssurroundings that can influence it in various ways. For example,body weight in humans may be influenced by genes but is alsoinfluenced by diet. In this case, diet is an example of anenvironmental factor.

I NEED B ANSWERED!!!

Is A correct? I might be wrong I'm terrible at thisclass please help