Tag: selection and evolution

Questions Related to selection and evolution

An example of polygenic inheritance

biology selection and evolution phylogeny cladistics speciation

  1. Epistasis

  2. Dominance

  3. Segregation

  4. Pleiotropy

  5. Independent assortment

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Correct Option: A
Explanation:
Polygenic inheritance occurs when one characteristic is controlled by two or more genes e.g., height, skin color, eye color and weight.
Epistasis is a 'modifier genes', occurs when two or more different gene loci contribute to the same phenotype. In epistasis, one gene locus masks or modifies the phenotype of a second gene locus. Thus, the correct answer is option A.

The correct explanation for the descent of all organisms through evolution from a common ancestor is given by the fact that

biology selection and evolution phylogeny cladistics speciation

  1. There is much evidence for the occurrence of convergent evolution

  2. It is widely accepted that natural selection leads to evolution

  3. Despite the diversity of organisms on Earth, all share the same genetic code

  4. All populations experience mutation and natural selection

  5. Selection acts on individuals, but only populations evolve

Show answer
Correct Option: C
Explanation:
Option 'C' is correct.
The genetic code is universal. This means that the same amino acid is present in all organisms. There are about 20 amino acids and 64 codons.

Which of the following is associated with the theory of evolution based on the study of the genetic makeup of species at the DNA level?

biology selection and evolution phylogeny cladistics speciation

  1. Biogeography

  2. Natural selection

  3. Comparative anatomy

  4. Comparative embryology

  5. Molecular biology

Show answer
Correct Option: E
Explanation:

Describing the process of evolution in terms of past and present geographic distribution of species is termed as biogeography. Evolutionary theories based on comparative study of the structural details of features found in different but related organisms reveals the process of evolution in terms of basic similarities and differences among them. These are termed as comparative anatomy. Comparative embryology defines the process of evolution in terms of basic similarities and differences in embryological development.  Natural selection is the evolutionary force that favors the mutation conferring “fitness” to organisms thereby leading to the evolution of fittest species. Evolutionary theories based on similarities and differences in DNA sequences of different but related species defines their evolution in terms of molecular biology. Thus, the correct answer is option E.

Different species of organisms share a common ancestry based on

biology selection and evolution phylogeny cladistics speciation

  1. The amino acid sequence of their cytochrome C

  2. Their ability to synthesize hemoglobin

  3. The percentage of their body weight that is fat

  4. The percentage of their body surface that is used in gas exchange

  5. The mechanism of their mode of locomotion

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Correct Option: A

One goal of phylogenetic systematics is to make classification of organisms more objective and consistent with evolutionary history. Select the incorrect statement regarding this important area of study.

biology selection and evolution phylogeny cladistics speciation

  1. The two main analytical approaches to the study of phylogenetic systematics are phenetics and cladistics

  2. Phenetic analysis compares as many characters as possible without distinguishing between homologous and analogous characters

  3. Cladistic analysis classifies organisms according to the order in time that branches arose along a dichotomous phylogenetic tree

  4. Cladistic analysis relies on analogous characters among organisms while ignoring novel homologies unique to the various organisms on a branch

  5. The most accurate phylogenetic trees are those in which molecular data agree with other forms of evidence for phylogenetic relationships (such as morphology, fossil records, and biochemical analysis)

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Correct Option: D

The more recently two species shared a common ancestor

biology selection and evolution phylogeny cladistics speciation

  1. The greater their morphological differences will be.

  2. The less their DNA sequences will match.

  3. The more their DNA sequences will match.

  4. The more variation there will be in their amino acid sequences.

Show answer
Correct Option: C
Explanation:

If two species have evolved from a recent ancestor, there will be a greater DNA match between the two newly formed species and also the ancestor.

So, the correct answer is 'The more their DNA sequences will match'

In order to compare the evolutionary relationships among species, the scientists used cytochrome-c protein. A study on cytochrome-c protein revealed one difference between humans and rhesus monkeys and ten differences between humans and kangaroos. What can be concluded from this study?

biology selection and evolution phylogeny cladistics speciation

  1. Humans and kangaroos have the same proteins coded in their genes.

  2. Humans and kangaroos share a more recent ancestor than humans and rhesus monkeys.

  3. Humans are not closely related to either kangaroos or rhesus monkeys.

  4. Humans and rhesus monkeys share a more recent ancestor than human and kangaroos.

  5. Rhesus monkeys and kangaroos share a more recent ancestor than humans and rhesus monkeys.

Show answer
Correct Option: D
Explanation:

Organisms that share more amino acid sequence homology for commonly occurring proteins are supposed to be diverged from each other recently and share more recent ancestors. Since cytochrome c protein of human and rhesus monkey exhibit single difference while those of human and kangaroos exhibit ten differences, human and rhesus monkey are supposed to share more recent ancestors than human and kangaroos. Thus, the correct answer is D.

Which of the of the following would be least useful in constructing a phylogeny or cladogram?

speciation cladistics phylogeny selection and evolution biology

  1. DNA comparisons

  2. Environment comparisons

  3. Morphology comparisons

  4. Protein comparisons

Show answer
Correct Option: B
Explanation:
Phylogeny is related to how an organism has originated, this could be done using comparison of DNA, morphology and proteins as proteins are formed from the DNA. However environment does not influence a phylogenetic tree or cladogram
So, the correct answer is 'Environment comparisons'

 Which one cannot determine phylogenetic relationships?

biology selection and evolution phylogeny cladistics speciation

  1. Physiology

  2. Biogeography

  3. Morphology

  4. Embryology

Show answer
Correct Option: A
Explanation:

Different organism show similarities in physiology and biochemistry thus proved that all animals have evolved from same common ancestor determining phylogenetic relationships.

So, the correct option is 'Physiological'.

The red viscacha rat has almost twice as many chromosomes as one of its closest relatives, the mountain viscacha rat.

What mechanism most likely resulted in the evolution of the red viscacha rat?

biology selection and evolution phylogeny cladistics speciation

  1. Errors in replication

  2. Errors in meiosis

  3. Environmental adaptations

  4. Unequal crossover

Show answer
Correct Option: B
Explanation:

The doubling of its chromosome number was presumably by errors in mitosis or meiosis within the animal's reproductive organs.A comparison of the chromosomes of the red viscacha rat and the mountain viscacha rat suggested that the chromosomes of the red viscacha rat increased relatively rapidly (in evolutionary terms) due to a diverse set of highly repetitive elements. So, the correct answer is " Errors in meiosis".