Evolution and Behavior MCQ Quiz in मल्याळम - Objective Question with Answer for Evolution and Behavior - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is stabilizing.

Explanation:

Stabilizing selection favors individuals with intermediate values of a trait, reducing variation around the mean. It does not increase variation.

• An example of this is human birth weight — babies of low weight lose heat more rapidly and get ill from infectious diseases more easily, while babies of large weight are more difficult to deliver. Babies of medium weight survive most often.
• Directional selection tends to favor one extreme phenotype, thus changing the average value of a trait.
• Stabilizing selection favors intermediate variants and acts against extreme phenotypes, reducing variation in a trait over time.
• Disruptive selection favors the extreme phenotypes over intermediates, thereby increasing variation in a trait. Disruptive selection favors individuals at both extremes of a trait, leading to an increase in variation. It promotes the divergence of traits within a population.
• Balancing selection maintains variation in a trait, as multiple alleles are actively maintained in the gene pool.

The correct answer is Option 1 i.e.A ‐ IV, B ‐ III, C ‐ I, D ‐ II

Concept:  

• A cell or an organism's behavioural response to outside stimuli is called taxis.
• It is different from kinesis which is a behavioural reaction that results in the movement of organisms in response to an external stimulus.  
• In the case of kinesis, the movement is random or not directionally oriented, whereas in the case of taxis the movement is directionally oriented.
• The movement could be favourable or unfavourable.
• When an organism or cell is travelling toward the source of stimulus, this is referred to as a positive taxis (attraction).
• When a cell or an organism is travelling away from the source of stimulation, this is referred to as a negative taxis (repulsion).
• Taxis also differ from tropism, an automatic, either positive or negative, orienting response to a stimulus source.
• Different types of taxis movement are involved. 

Important Points

• Menotaxis -
  • It is a movement where the organism is maintaining a constant angle to a stimulus.
  • Silk moth flies moving in the direction perpendicular to the wind (stimuli) in order to locate the scent trial is an example of Menotaxis. 
• Magnetotaxis - 
  • ​It is the passive orientation and active movement of organisms in the response to the magnetic field.
  • The movement of bacteria in the response to the magnetic field and burrowing is an example of magnetotaxis.
• Mnemotaxis -
  • It is also known as 'memory response', that is navigation with the use of landmarks.
  • The girl using landmarks to travel to her school is an example of Mnemotaxis. 
• Klinotaxis -
  • It is the wavering side-by-side motion of a part of the body(head) or all of the body, as the organism is moving in the direction of the stimulus.
  • The movement of planaria towards the higher concentration of food by comparing the stimuli is an example of klinotaxis.

Hence, the correct answer is Option 1.

The correct answer is Option 2 i.e. D-C-B-A

Concept:

• The geological time scale is a chronological sequence of evolutionary and geological events spanning the physical formation and development of the Earth.
• In essence, the geological time scale is the Earth's history that is been recorded and represented in the rock strata of the Earth.
• The geological time scale is divided into descending order of duration- eon, era, period, epoch and age.
• The name of division is mainly based on the fossil evidences and principle of carbon dating and most of the boundaries correspond with the origination of extinction of particular kinds of fossils.

Explanation:

• Cambrian period extended from 541 million to 485.4 million years ago.
• Jurassic period extended from 199.6 million to 145.5 million years ago.
• Cretaceous period extended from 145.5 million years to 66 million years ago.
• Quaternary period extended from 2.58 million years to today.

So, the correct order from earlier to recent is Cambrian - Jurassic - Cretaceous - Quaternary. 

Hence, the correct answer is D - C - B - A.​​

The correct answer is Option 4 i.e.Living fossils are organisms that have remained unchanged for millions of years. 

Concept:

• An organism that has stayed largely the same over millions of years with no or few close surviving relatives is considered as a living fossil.
•  The phrase "living fossil" was first used by English biologist Charles Darwin in 1859 to describe a species or group of animals that have altered very little over time as to offer insight into older, now-extinct forms of life.
• Charles Darwin was of the opinion that these organisms are still evolving and these species have adapted to their environmental controls, thereby reaching a peak of competence in environments which leads to the constant strengthening of certain physical characteristics.
• Thus these physical characteristics are still prevalent even after millions of years. 
• Example of living fossils :
  • Unicellular - Cyanobacteria, Amoeba and Protozoa
  • Multicellular - Coelacanth,  Goblin shark, Opossum, Lamprey and Platypus

Explanation:

• Option 1: Living fossils are impressions of extant organisms in old rocks.
  • ​Impression is the 2-D imprint of an organism and it does not contain any organic material.
  • It is a clue left as to the activity performed by the organism. 
  • Some examples of impressions are the footprints, remains of tunnels fossilized excreta of organisms, etc.
  • Hence, this is an incorrect option.
• Option 2: Living fossils show high morphological divergence from fossil records.
  • ​Living fossils closely resemble their fossilized relatives, so they do not show any morphological divergence.
  • This is an incorrect option.
• Option 3: Living fossils are always an evolutionary link between two classes of organisms.
  • ​Connecting link is the organism are the evolutionary link between two organisms as they share characteristics from both classes.
  • Hence, this is an incorrect option.
• Option 4: Living fossils are organisms that have remained unchanged for millions of years. 
  • Living fossils are organisms that have existed for millions of years and they have still remained mostly unchanged.
  • For example, Horseshoe crab is a living fossil as it has remained unchanged for 445 million years. 
  • Even today horseshoe crabs are living and we also find fossils of some species of horseshoe crab some 445 million years ago. 
  • Hence, this is the correct option.

Hence, the correct answer is Option 4.

The correct answer is 12.5

Explanation:

• Random genetic drift is the change in the frequency of an existing gene variant (allele) in a population due to random sampling of organisms.
• Genetic drift acts more strongly in small populations and can lead to the fixation or loss of alleles over time.
• In a population of 12 individuals, with 2 Bb genotype and 10 BB genotypes.
• Each individual has 2 alleles, so there are (12 x 2 = 24) alleles in total per population. 
• The initial frequency of the "b" allele is 2/24 = 1/12
• Over a large number of generations, genetic drift can lead to either the loss or fixation of the "b" allele in each population.
• The probability of the "b" allele getting fixed in a population is equal to its initial frequency.
• In this case, the initial frequency of the "b" allele is 1/12.

Therefore, out of 150 independent populations, the expected number of populations in which the "b" allele becomes fixed is 1/12 x 150 = 12.5.

The correct answer is Gene duplication.

Explanation:

In phylogenetic analysis, different molecular mechanisms can explain the evolutionary relationships observed between species. Let's break down the given options:

1. Gene duplication:

   • Gene duplication is a common evolutionary mechanism where genes are copied in an organism's genome. These duplicated genes can evolve new functions or maintain the same function.
   • Gene duplication can lead to the creation of gene families, and the resulting phylogenetic tree may show patterns similar to those observed in the question.

2. Horizontal gene transfer:

   • Horizontal gene transfer (HGT) involves the transfer of genes between different species, not from parent to offspring. This phenomenon is more common in prokaryotes (bacteria) and can sometimes create unusual phylogenetic patterns.
   • While HGT can be significant in shaping genomes, it is less likely to explain the relationships shown in the tree for these species.

3. Hybridization:

   • Hybridization occurs when two species interbreed, resulting in offspring that may have mixed genetic information from both parents.
   • Although hybridization can influence phylogenetic relationships, the structure of the tree in this case is more indicative of gene duplication events rather than hybridization.

4. Genome rearrangement:

   • Genome rearrangement refers to large-scale changes in the structure of chromosomes, such as inversions, translocations, and duplications.
   • While this can influence species evolution, it does not necessarily explain the specific branching pattern in the phylogenetic tree shown.

Key Points

• Gene duplication can lead to multiple gene copies evolving separately, which explains the branching pattern in the tree.
• Horizontal gene transfer typically occurs between unrelated species, and is less likely to explain this particular tree.
• Hybridization can influence phylogenetic relationships but does not fully account for this gene family-like tree structure.
• Genome rearrangement can alter evolutionary trajectories but does not directly lead to the pattern observed in the tree.

Conclusion:

The correct answer is Option 1, as gene duplication is the most plausible mechanism responsible for the phylogenetic relationships shown between species W, X, Y, and Z.

The correct answer is Option 3

Explanation:

Artiodactyls are a group of even-toed ungulates, which include animals like pigs, hippos, camels, and cows. Molecular and genetic studies have shown that whales (cetaceans) are most closely related to a subgroup of artiodactyls, particularly hippos.

• Tree 1: Shows whales sharing a recent ancestor with camels and horses. This is incorrect because whales are not most closely related to camels or horses.
• Tree 2: Shows whales sharing a common ancestor with pigs and horses, while hippos are distantly related. This is also incorrect because molecular data place whales closer to hippos than to pigs or horses.
• Tree 3: Shows whales sharing a most recent common ancestor with hippos, with both whales and hippos branching off from a common ancestor they share with pigs. This is the correct representation, as it aligns with the molecular evidence.
• Tree 4: Shows whales branching off from a common ancestor shared with pigs, hippos, and camels. While this includes relevant species, it does not accurately reflect the specific close relationship between whales and hippos.

The correct answer is Genotype frequencies: 0.64 WW 0.32 Ww and 0.04 Ww Allele Frequencies W-0.8 and w-0.2

Explanation:
The total population size is given as 500 individuals.

Given genotypes:

• WW: 320 individuals
• Ww: 160 individuals
• ww: 20 individuals

Genotype frequency is calculated as the number of individuals with the genotype divided by the total population size.

• Frequency of WW (p²): Frequency of WW = no of WW individuals / Total no of indiviuals = 320/500= 0.64
• Frequency of Ww (2pq): No. of Ww individuals / Total no of individuals = 160/500= 0.32
• Frequency of ww (q²): No of ww individuals / Total no of individuals= 20/500= 0.04

Calculate the total number of each allele in the population. Each individual contributes two alleles.

Number of W alleles:

• From WW individuals: ( 320 X 2 = 640 )
• From Ww individuals: ( 160 X 1 = 160 )
• Total W = 640 + 160=800

Number of w alleles:

• From ww individuals: ( 20 X 2 = 40 )
• From Ww individuals: ( 160 X 1 = 160 )
• Total w = 40+160= 200

Next, calculate the total number of alleles in the population:

Total alleles in the population = 2 x (Number of individuals} = 2 x 500 = 1000 

Now, determine the allele frequencies:

• Frequency of W (p): 800/1000= 0.8
• Frequency of w (q): 200/1000 = 0.2

Summary
Genotype Frequencies:

• WW: 0.64
• Ww: 0.32
• ww: 0.04

Allele Frequencies:

• W: 0.8
• w: 0.2

The correct answer is:Several species are involved in coevolutionary interactions.

Concept:

Guild coevolution, also known as diffuse coevolution, refers to coevolutionary interactions that involve multiple species rather than just two. In this type of coevolution, several species interact and exert selective pressures on each other in a more generalized way, rather than in a tightly coupled, pairwise interaction. These species belong to the same guild—a group of species that exploit the same kinds of resources or face similar ecological pressures.

• For example, a group of plants may evolve defenses like toxins or thorns to protect against a guild of herbivores (e.g., insects, mammals), and in response, the herbivores may evolve mechanisms to overcome those defenses. These coevolutionary dynamics occur not between just one plant and one herbivore but across multiple species.

Explanation:

• "One species uses the other as a resource": This describes a trophic interaction like predation or parasitism, not coevolution, which involves reciprocal evolutionary changes.
• "Two species coevolve reciprocally, but only to each other": This describes pairwise coevolution, where two species (such as a specific predator and prey or plant and pollinator) directly influence each other’s evolution. Diffuse coevolution, on the other hand, involves multiple species.
• "A species escapes association from a predator and diversifies. Later, a different predator adapts to the host and diversifies.": While this describes an evolutionary process, it suggests a sequence of events involving specific species, not the broader network of interactions typical of guild coevolution.

Thus, the statement "Several species are involved in coevolutionary interactions" best describes guild coevolution.

The correct answer is Devonian

Explanation:

• The Devonian period, which lasted about 45 million years starting from approximately 325 million years ago, saw the first known forests and gymnosperms.
• This period is characterized by the diversification of plant life, including the emergence of the first known liverworts, horsetails, and ferns, as well as significant diversification in fish and the evolution of amphibians.
• This era is sometimes referred to as the "Age of Fishes" due to the diversity and abundance of fish species that existed.