State and explain any three factors affecting allele frequency in populations.
(i) Gene migration or gene flow: When migration of a section of population to another place and population occurs, gene frequencies change in the original as well as in the new population. New genes/alleles are added to the new population and these are lost from the old population. There would be a gene flow if this gene migrationhappens multiple times.
(ii) Genetic drift: If the same change occurs by chance, it is called genetic drift. Sometimes the change in allele frequency is so different in the new sample of population that they become a different species. The original drifted population becomes founders and the effect is called founder effect.
(iii) Mutation: Microbial experiments show that pre-existing advantageous mutations when selected will result in observation of new phenotypes. Over few generations, this would result in speciation. Natural selection is a process in which heritable variations enabling better survival are enabled to reproduce and leave greater number of progeny.
Name the law that states that the sum of allelic frequencies in a population remains constant. What are the five factors that influence these values?
Give an example for convergent evolution and identify the features towards which they are converging.
Among the five factors that are known to affect Hardy-Weinberg equilibrium, ‘ three factors are gene flow, genetic drift and genetic recombination. What are the other two factors?
When we say "survival of the fittest", does it mean that
a. those which are fit only survive, or
b. those that survive are called fit? Comment.
Find out from newspapers and popular science articles any new fossil discoveries or controversies about evolution.
While creation and presence of variation is direction less, natural selection is directional as it is in the context of adaptation. Comment.
Using various resources such as your school library or the internet and discussions with your teacher, trace the evolutionary stages of any one animal say horse.
The evolutionary story of moths in England during industrialisation reveals, that evolution is apparently reversible'. Clarify this statement.
Gene flow occurs through generations. Gene flow can occur across language barriers in humans. If we have a technique of measuring specific allele frequencies in different population of the world, can we not predict human migratory patterns in pre-history and history? Do you agree or disagree? Provide explanation to your answer.
In a certain population, the frequency of three genotypes is as follows:
Genotypes: BB, Bbbb
Frequency: 22%, 62%, 16%
What is the likely frequency of B and b alleles?
When we talk of functional macro-molecules (e.g., proteins as enzymes, hormones, receptors, antibodies etc.), towards what are they evolving?
You have studied the story of Pepper moths in England. Had the industries been removed, what impact could it have on the moth population? Discuss.
Louis Pasteur's experiments, if you recall, proved that life can arise from only pre-existing life. Can we correct this as life evolves from pre-existent life or otherwise we will never answer the question as to how the first forms of life arose? Comment.
List 10 modern-day animals and using the” internet resources link it to a corresponding ancient fossil. Name both.
Two organisms occupying a particular geographical area (say desert) show similar adaptive strategies. Taking examples, describe the phenomenon.
Find out through internet and popular science articles whether animals other than man has self-consciousness.
The scientists believe that evolution is gradual. But extinction, part of evolutionary story, are sudden' and abrupt' and also group-specific. Comment whether a natural disaster can be the cause for extinction of species.
Try to trace the various components of human evolution (hint: brain size and function, skeletal structure, dietary preference, etc.)
Had Darwin been aware of Mendel's work, would he been able to explain the origin of variations. Discuss.
Explain antibiotic, resistance observed in bacteria in light of Darwinian selection theory.
We are told that evolution is a continuing phenomenon for all living things. Are humans also evolving? Justify your answer.
Comment on the statement that "evolution and natural selection are end result or consequence of some other processes but themselves are not processes".