(a) (i) Define asexual reproduction. (ii) Name two types of asexual reproduction which occur in...
(a) (i) Define asexual reproduction.
(ii) Name two types of asexual reproduction which occur in animals giving one example in each case.
(b) In a tabular form outline four differences between sexual and asexual reproduction.
(c) Make a large, labelled diagram 8 - 10cm long of the human spermatozoon to show its structure.
(d) State one function each of any three organelles found in the spermatozoon.
Explanation
(a)(i) Definition of asexual reproduction: Asexual reproduction is the production of a new individual from a parent / organism / order individual, without fertilization / gametes / change in chromosome number/genetic constitution; it involves, a single parent.
(ii) Types of asexual reproduction in animals Types Example;
| Types | Example |
(1) Binary fission (2) Budding (3) Sporulation (4) Parthenogenesis (5) Schizogony (6) Fragmentation | Amoeba, Paramecium Hydra/Obelia Amoeba Aphids, Honey bee Plasmodium / Merozoides Planaria / Sponges / Hydroid Coelenterate |
(b) Differences between asexual and sexual reproduction Asexual reproduction
| Asexual reproduction | Sexual reproduction |
(1) One parent involved (2) No gametes formed (3) Meiosis not involved (4) No fertilization / fusion of gametes/ sex cell / no zygote formed (5) Offspring identical I. No genetic variation (6) Rapid / faster mode of reproduction (7) More individuals are produced | Two parents involved Gametes / sex cells formed meiosis involved Fertilization / fusion of gametes / sex cells occur zygote formed Offspring vary genetically Slower mode of reproduction Fewer individual are produced |
(d) Function of organelles;
- Acrosome- contains enzymes / lytic agents that help to digest the cell membrane of the female ovum during fertilization.
- Nucleus; contains haploid number of chromosomes / genetic materials / DNA
- Mitochondria;contain respiratory enzymes / for respiration that provide energy / site for production of energy for locomotion/ movement.