Heredity and Evolution

Because of the following factors, sexual reproduction leads to numerous viable variations: (a) A mistake in DNA copying (though it was rare) At the moment sex cells develop, paternal and maternal chromosomes are randomly segregated. (c) When gametes are formed, homologous chromosomes exchange genetic material. (d) Variations accumulated as a result of reproduction over many …

Explain how sexual reproduction gives rise to more viable variations than asexual reproduction. How does this affect the evolution of those organisms that reproduce sexually? Read More »

The experiment carried out in 1953 by Stanley L. Miller and Harold C. Urey proved that life originated from inanimate elements. They made an artificial atmosphere that resembled that of the early planet; it contained ammonia, hydrogen, and other gases believed to have existed during the prehistoric era of the world. The temperature of this …

What evidence do we have for the origin of life from inanimate matter? Read More »

Fossils give evidence about: (a) The organism and their paleobiology (b) Even an organism’s behaviour can be inferred to some extent. For instance, palaeontologists have discovered a site with more than 10,000 Hadrosaurus dinosaur skeletons. This suggests that the dinosaurs were a herd animal. (c) Fossils shed light on how animals and plants have developed …

Explain the importance of fossils in deciding evolutionary relationships. Read More »

Dogs’ coat colour is determined by a specific set of genes. The colour of a dog is governed by at least eleven recognised sequence series (A, B, C, D, E, F, G, M, P, S, and T). Every parent of a dog imparts one copy to the offspring. As an illustration, a dog in the …

Outline a project which aims to find the dominant coat colour in dogs Read More »

Homologous organs are those that share the same basic structural design and place of origin but have unique uses. Anatomically defined, human forelimbs and bat wings are similar. Analogous organs are those organs that have a different structural design as well as origin; however, they have similar functions. Example, the wings of birds and insects.

Biology’s classification and evolution fields are connected. The relationship between two species is determined by categorization, which has to do with how organisms evolve. For example, Australopithecus afarensis is one of our oldest ancestors, according to evolution and fossil evidence. And according to categorization, Australopithecus afarensis is a member of the Homo genus, the same …

How are the areas of study – evolution and classification – interlinked? Read More »

Answer – (a) Since they both belong to the same family and order (Primates), humans and chimpanzees are linked (Hominidae). However, a student is still a Homo sapien regardless of race.

Answer – (d) Homologous organs have the same origin as each of the above organs but different functions. The term “homologous organs” refers to organs from different species that have a similar basic structure but perform diverse tasks. For example, a whale’s flippers, a frog’s forelimbs, and a man’s have the same basic structures but …

An example of homologous organs is
(a) Our arm and a dog’s foreleg (b) Our teeth and an elephant’s tusks
(c) Potato and runners of grass
(d) All of the above Read More »

Correct answer – (c) TtWW might be the tall parent’s genetic makeup. The parent plant must also have a collection of short genes because half of the progeny are short. Additionally, all of the progeny produced violet blooms, further indicating that violet colour predominates over white.

Environmental demands and pressure have an effect on how organs are designed. As a result, we cannot draw the conclusion that one organism has a better body than another. For example, because it is best adapted for an aquatic environment, fish have evolved a streamlined shape. A spider or chimpanzee, on the other hand, might …

In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better’ body design? Why or why not? Read More »