Heredity and evolution Worksheet-13
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What is a gene?
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Write the scientific term used for 'science of heredity and variation.'
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Define inheritance.
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Name the scientist who proposed the theory of natural selection.
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What are analogous organs?
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Name the naturalist who put forward the theory of natural selection along with Darwin.
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Give two examples of analogous organs from animals.
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What are homologous organs? Give one example.
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What term did Mendel use for what we now call the genes?
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List the main concepts in Darwin's theory of Natural Selection.
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What is heredity?
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Name the plant on which Mendel performed his experiments.
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Define Variation.
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What is micro-evolution?
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Write the expanded form of DNA.
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What do you understand by evolution?
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Who is called "Father of Genetics"?
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What are the carriers of factors or genes?
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Give an example of homologous organ from the plant kingdom.
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Why can the wings of a bird and the wings of a bat not to be considered analogous?
Answer:
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Gene is the unit of inheritance. It is therefore, a unit of specific biological function. Gene is the part of a chromosome which controls the appearance of a set of hereditary characteristics.
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Genetics.
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Inheritance is the transmission of particular characteristics from generation to generation by means of the genetic code, which is transferred to offspring in the gametes.
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Charles Darwin.
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Analogous organs are those organs which have different basic structure and development origin
but have similar appearance and perform similar functions.
e.g., wings of an insect (butterfly) and a bird.
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Alfred Wallace.
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(i) Wings of insects and those of birds. (ii) Wings of insects and those of bats.
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Homologous organs are those organs which have the same basic structural design and
developmental origin but have different functions and appearance.
Example: The forelimb of a frog, a lizard, a bird and a man seem to be built from the same basic design of bones, but they perform different functions.
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Factors.
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Darwin explained evolution with the help of his theory of natural selection.
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Heredity refers to the transmission of characters or traits from the parents to their offspring.
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Garden Pea (Pisum sativum).
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Variation refers to the differences in the characters or traits among the individuals of a species.
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Micro-evolution is the evolution on a relatively small scale, involving the emergence of new species or of new groups below the species level, such as races and sub-species which are significant. They also change the common characteristics of a particular species.
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DNA - Deoxyribonucleic Acid.
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Evolution is the sequence of gradual changes which takes place in the primitive organisms over million of years in which new species are produced.
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Gregor Johann Mendel.
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Chromosomes.
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Thorns and tendrils.
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Wings of bird and a bat are modified forelimbs and hence show structural similarity. Hence they cannot be considered as analogous structures.