Origin and Evolution of life

The living matter shows attributes or characters like responsiveness, growth, metabolism, energy transformations and reproduction

What is genetic variations? Explain the different factors responsible for genetic variations.

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Genetic variation refers to the diversity in DNA sequences among individuals within a population, occurring in both germ cells (sperm and egg) and somatic cells (all other cells). Genetic variations are caused by following factors: I. Mutation: • Definition: Sudden, permanent heritable changes. • Types: Gene mutation (point mutation), chromosome structure mutation, chromosome number mutation. • Effect: Alters … Read more

What is isolation? Describe different type of reproductive isolation.

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Isolation refers to the division of a species’ population into smaller units, where organisms in these subunits are hindered from interbreeding by barriers known as isolating mechanisms. Different type of reproductive isolation are as follows: I. Geographical Isolation: • Physical barriers like rivers, oceans, mountains, or glaciers divide the original population. • Organisms can’t cross these … Read more

Describe the Urey and Millers experiment.

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Stanley L. Miller and Harold C. Urey’s Experimental Support for Oparin’s Chemical Evolution Theory: Apparatus and Procedure: Miller and Urey devised a spark-discharge apparatus, a glass chamber, to experimentally validate Oparin’s chemical evolution theory. The apparatus was sterilized, evacuated, and filled with methane, ammonia, and hydrogen gases in a 1:2:2 ratio. A tube introduced water … Read more

By talking industrial melanism as one example. Explain the concept of natural selection.

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1. Industrial melanism, a prime example of natural selection studied by Kettlewell, involved two UK peppered moth varieties: Biston betularia and Biston carbonaria. 2. In pre-industrial Britain, Biston betularia outnumbered Biston carbonaria. B. Betularia was greyish-white, while B. carbonaria had a melanic form. 3. Nocturnal moths rested on tree trunks during the day. White-winged moths … Read more

What is adaptive radiation? Explain with suitable example.

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1. Adaptive radiation, a pivotal process in evolution, entails the transformation of an original species into a diverse array of varieties. 2. A notable illustration of adaptive radiation is found in Darwin’s Finches. During Charles Darwin’s exploration of the Galapagos Islands, he observed a variety of small birds known as finches. 3. Darwin’s observations suggested … Read more

Would you consider wings of butterfly and bat as homologous or analogous and why?

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The wings of a butterfly and a bat are analogous, meaning they share similar functions but do not have a common evolutionary origin. Examples of analogous structures include: 1. Butterfly wings and bird wings may appear similar, but they are not anatomically alike, despite serving similar functions. 2. The eyes of an octopus and mammals … Read more

What is disrruptive selection? Give example.

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Disruptive selection, also referred to as diversifying selection, occurs when genetic changes in a population favor extreme trait values rather than intermediate ones. This leads to an increase in the variation of the trait, causing the population to split into two distinct groups. Examples of disruptive selection include the beak size variation among Galapagos finches … Read more

Write the objections to Mutation theory of Hugo de vries.

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1. Hugo de Vries found significant variations, with major changes linked to chromosomal issues and smaller changes to gene mutations. 2. Mutations happen slower than what’s needed for evolution to bring about significant transformations. 3. Chromosomal problems are unstable and often lead to sterile organisms, limiting their impact on evolution due to challenges in reproduction.

Give the significance of fossils.

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1. Fossils are the remains of ancient plants and animals found in different layers of the Earth. 2. The study of fossils gives us strong and direct proof of how evolution works. 3. Fossil studies show that life forms were not the same millions of years ago. 4. The geological timescale, which helps us understand … Read more