1. The evolution of horse started with Eohippus during Eocene period. It involved the following evolutionary stages. (i) Gradual increase in body size (ii) Elongation of head and neck region (iii) Increase in the length of limbs and feet (iv) Gradual reduction of lateral digits (v) Enlargement of thirdRead more

    The evolution of horse started with Eohippus during Eocene period. It involved the following evolutionary stages.
    (i) Gradual increase in body size
    (ii) Elongation of head and neck region
    (iii) Increase in the length of limbs and feet
    (iv) Gradual reduction of lateral digits
    (v) Enlargement of third functional toe
    (vi) Strengthening of the back
    (vii) Development of brain and sensory organs
    (viii) Increase in the complexity of teeth for feeding on grass
    The evolution of horse is represented as
    (i) Eohippus
    It had a short head and neck. It had four functional toes and a splint of 1 and 5 on each hind limb and a splint of 1 and 3 in each forelimb. The molars were short crowned that were adapted for grinding the plant diet.
    (ii) Mesohippus
    It was slightly taller than Eohippus. It had three toes in each foot.
    (iii) Merychippus
    It had the size of approximately 100 cm. Although it still had three toes in each foot, but it could run on one toe. The side toe did not touch the ground. The molars were adapted for chewing the grass.
    (iv) Pliohippus
    It resembled the modern horse and was around 108 cm tall. It had a single functional toe with splint of 2nd and 4th in each limb.
    (v) Equus
    Pliohippus gave rise to Equus or the modern horse with one toe in each foot. They have incisors for cutting grass and molars for grinding food.

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  2. No, human evolution cannot be called adaptive radiation. This is because adaptive radiation is an evolutionary process that produces new species from a single, rapidly diversifying lineage, which is not the case with human evolution. Human evolution is a gradual process that took place slowly in timRead more

    No, human evolution cannot be called adaptive radiation. This is because adaptive radiation is an evolutionary process that produces new species from a single, rapidly diversifying lineage, which is not the case with human evolution. Human evolution is a gradual process that took place slowly in time. It represents an example of anagenesis.

     

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  3. Adaptive radiation is an evolutionary process that produces new species from a single, rapidly diversifying lineage. This process occurs due to natural selection. An example of adaptive radiation is Darwin finches, found in Galapagos Island. A large variety of finches is present in Galapagos IslandRead more

    Adaptive radiation is an evolutionary process that produces new species from a single, rapidly diversifying lineage. This process occurs due to natural selection. An example of adaptive radiation is Darwin finches, found in Galapagos Island. A large variety of finches is present in Galapagos Island that arose from a single species, which reached this land accidentally. As a result, many new species have evolved, diverged, and adapted to occupy new habitats. These finches have developed different eating habits and different types of beaks to suit their feeding habits. The insectivorous, blood sucking, and other species of finches with varied dietary habits have evolved from a single seed eating finch ancestor.

     

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  4. There are many animals other than humans, which have self-consciousness. An example of an animal being self-conscious is dolphins. They are highly intelligent. They have a sense of self and they also recognize others among themselves and others. They communicate with each other by whistles, tail-slaRead more

    There are many animals other than humans, which have self-consciousness. An example of an animal being self-conscious is dolphins. They are highly intelligent. They have a sense of self and they also recognize others among themselves and others. They communicate with each other by whistles, tail-slapping, and other body movements. Not only dolphins, there are certain other animals such as crow, parrot, chimpanzee, gorilla, orangutan, etc., which exhibit self-consciousness.

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  5. Species can be defined as a group of organisms, which have the capability to interbreed in order to produce fertile offspring.   For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-12/biology/chapter-7/

    Species can be defined as a group of organisms, which have the capability to interbreed in order to produce fertile offspring.

     

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