modes of repro Flashcards
(15 cards)
what is reproduction
reproduction is a biological process by which an organism reproduces an offspring biologically similar to organisms
- it enables and ensures the continuity of species generation after generation and is the main feature of life on earth
what is asexual reproduction
the process resulting in production of genetically identical offspring from one parent
differences in asexual reproduction and sexual reproduction?
- one parent (asexual) two parents (sexual)
- no fusion of gametes (asexual) fusion of gametes (sexual)
- genetically identical (asexual) genetcially disimilar (sexual)
- mitosis (asexual) meiosis (sexual)
advantages of asexual reproduction
- only one parent needed
- fusion of gametes not required
- all beneficial qualities are passed to offspring
faster method of producing offspring
disadvantages of asexual reproduction
- no genetic variation in off spring hence species are not well adapted
what is mitosis
a type of cell division (nuclear division) giving rise to genetically identical cells in which chromosome number must be maintained
what is the importance of mitosis
- for growth
- repair
- asexual repro
what is meiosis
a nuclear division that produces daughter nuclei containing half the number of chromosomes (haploid) as the parent nucleus due to the separation of homologous chromosomes
what is sexual reproduction
the fusion of nuclei of male and female gametes to form a zygote and production of genetically dissimilar offspring
what are the advantages of sexual reproduction
offspring can inherit beneficial qualities from both parents
genetic variation in offspring leads to better adaptation to changes in environment
disadvantages of sexual reproduction
- 2 parents required
- fusion of gametes required
- lower production of offspring
where does meiosis take place in
- gonads (e.g ovaries and testes) to form gametes (e,g sperm cell and ovum)
why is reduction division (formation of gametes) necessary prior to fertilization
meiosis produces haploid gametes which fuses during fertilization, so diploid number of chromosomes in zygote is restored
what are homologous chromosomes
pairs of chromosomes, one maternal and one paternal in origin
same shape same length contain similar genes
importance of meiosis
produces haploid gametes (reduction divison
- ensures no of chromosome in an organism is maintained through successive generations to prevent the doubling of chromosomes for each successive generation
creates genetic variation
- due to the crossing over between non-sister chromatids of homologous chromosomes and independent assortment of chromosomes
variations increases chances of survival of species during change in environment
- since fertilization is random such variations in gametes produce variations in offspring
- variation in spices allow for better resistance to changes in environment = better survival
