Homologous organs - The study of homologous organs suggests that the organs having same structure, but performing different functions, have evolved from a common ancestor. Example: Forelimbs of a frog, lizard, bird and man are homologous organs. Analogous organs - They show adoption of organs for coRead more
Homologous organs – The study of homologous organs suggests that the organs having same structure, but performing different functions, have evolved from a common ancestor.
Example: Forelimbs of a frog, lizard, bird and man are homologous organs.
Analogous organs – They show adoption of organs for common use.
Example: Wings of butterfly and wings of bat are analogous organs.
Fossils – They provide the missing links between two species.
Example: Archeopteryx/fossils of some dinosaurs with feathers. Archeopteryx provides a connecting link between reptiles and birds (Avian).
Significance of reproductive health in the society: (i) Prevention of STDs, (ii) Advantage of small family, (lii) Less mortality among newborns, (iv) Reduces the cases of maternal mortality. Related areas which have improved over the last 50 years: - Family Planning - Decrease in STD cases
Significance of reproductive health in the society:
(i) Prevention of STDs,
(ii) Advantage of small family,
(lii) Less mortality among newborns,
(iv) Reduces the cases of maternal mortality.
Related areas which have improved over the last 50 years:
– Family Planning
– Decrease in STD cases
Chromosomes: These are thread-like structures made up of DNA found in the nucleus. The original number of chromosomes becomes half during gamete formation. Hence, when the gametes combine, the original number of chromosomes gets restored in the progeny.
Chromosomes: These are thread-like structures made up of DNA found in the nucleus. The original number of chromosomes becomes half during gamete formation. Hence, when the gametes combine, the original number of chromosomes gets restored in the progeny.
Specific characteristics of sexual reproduction: (l) Two partners are involved. (ii) Two dissimilar gametes are formed, gamete formation involves meiosis. (lii) Variations are produced. (iv) It occurs in all the higher and some of the lower organisms. (v) Fertilization/fusion of gametes leads to zygRead more
Specific characteristics of sexual reproduction:
(l) Two partners are involved.
(ii) Two dissimilar gametes are formed, gamete formation involves meiosis.
(lii) Variations are produced.
(iv) It occurs in all the higher and some of the lower organisms.
(v) Fertilization/fusion of gametes leads to zygote formation.
(vi) It is comparatively a slow process.
(vii) Each partner produces gamete – sperms (male) .
(viii) Ova or egg (Female).
Electronic configuration of element with atomic number 16 is 2, 8, 6. Since it has 3 shells, the period number will be 3. Since the number of valence electrons is 6, the group number will be 10 + 6 = 16. Valency of the element will be 8 - valence electrons, i.e. 8 - 6 = 2.
Electronic configuration of element with atomic number 16 is 2, 8, 6.
Since it has 3 shells, the period number will be 3.
Since the number of valence electrons is 6, the group number will be 10 + 6 = 16.
Valency of the element will be 8 – valence electrons, i.e. 8 – 6 = 2.
Explain with an example for each, how the following provides evidences in favour of evolution in organisms: (a) Homologous organs (b) analogous organs (c) Fossils.
Homologous organs - The study of homologous organs suggests that the organs having same structure, but performing different functions, have evolved from a common ancestor. Example: Forelimbs of a frog, lizard, bird and man are homologous organs. Analogous organs - They show adoption of organs for coRead more
Homologous organs – The study of homologous organs suggests that the organs having same structure, but performing different functions, have evolved from a common ancestor.
See lessExample: Forelimbs of a frog, lizard, bird and man are homologous organs.
Analogous organs – They show adoption of organs for common use.
Example: Wings of butterfly and wings of bat are analogous organs.
Fossils – They provide the missing links between two species.
Example: Archeopteryx/fossils of some dinosaurs with feathers. Archeopteryx provides a connecting link between reptiles and birds (Avian).
List four points of significance of reproductive health in a society. Name any two areas related to reproductive health which have improved over the past 50 years in our country.
Significance of reproductive health in the society: (i) Prevention of STDs, (ii) Advantage of small family, (lii) Less mortality among newborns, (iv) Reduces the cases of maternal mortality. Related areas which have improved over the last 50 years: - Family Planning - Decrease in STD cases
Significance of reproductive health in the society:
See less(i) Prevention of STDs,
(ii) Advantage of small family,
(lii) Less mortality among newborns,
(iv) Reduces the cases of maternal mortality.
Related areas which have improved over the last 50 years:
– Family Planning
– Decrease in STD cases
What are chromosomes? Explain how in sexually reproducing organisms the number of chromosomes in the progeny is maintained.
Chromosomes: These are thread-like structures made up of DNA found in the nucleus. The original number of chromosomes becomes half during gamete formation. Hence, when the gametes combine, the original number of chromosomes gets restored in the progeny.
Chromosomes: These are thread-like structures made up of DNA found in the nucleus. The original number of chromosomes becomes half during gamete formation. Hence, when the gametes combine, the original number of chromosomes gets restored in the progeny.
See lessList six specific characteristics of sexual reproduction.
Specific characteristics of sexual reproduction: (l) Two partners are involved. (ii) Two dissimilar gametes are formed, gamete formation involves meiosis. (lii) Variations are produced. (iv) It occurs in all the higher and some of the lower organisms. (v) Fertilization/fusion of gametes leads to zygRead more
Specific characteristics of sexual reproduction:
See less(l) Two partners are involved.
(ii) Two dissimilar gametes are formed, gamete formation involves meiosis.
(lii) Variations are produced.
(iv) It occurs in all the higher and some of the lower organisms.
(v) Fertilization/fusion of gametes leads to zygote formation.
(vi) It is comparatively a slow process.
(vii) Each partner produces gamete – sperms (male) .
(viii) Ova or egg (Female).
Taking the example of an element of atomic number 16, explain how the electronic configuration of the atom of an element relates to its position in the modern periodic table and how valency of an element is calculated on the basis of its atomic numb
Electronic configuration of element with atomic number 16 is 2, 8, 6. Since it has 3 shells, the period number will be 3. Since the number of valence electrons is 6, the group number will be 10 + 6 = 16. Valency of the element will be 8 - valence electrons, i.e. 8 - 6 = 2.
Electronic configuration of element with atomic number 16 is 2, 8, 6.
See lessSince it has 3 shells, the period number will be 3.
Since the number of valence electrons is 6, the group number will be 10 + 6 = 16.
Valency of the element will be 8 – valence electrons, i.e. 8 – 6 = 2.