Reproduction S. G. p. 1
|Define Asexual reproduction, and describe 3 major forms.||Asexual reproduction occurs when offspring are produced from a single parent, without the fusion of genetic material from two parents. |
1) Budding: seen in cnidarians; occurs when a portion of the parent organism pinches off to form a complete new individual.
2) Regeneration: seen in sponges, worms, and echinoderms; when rep ruction occurs by the regeneration of a couple organism from small fragments of their body
3) Parthenogenesis: seen in several species of fish and reptiles; development of offspring from an unfertilized egg.
|Define Sexual Reproduction, and explain why sexual reproduction is considered evolutionarily more adaptive than asexual reproduction.||Sexual reproduction is the production of a new individual by the joining of two haploid reproductive cells called gametes, one from each parent.|
Sexual reproduction is considered evolutionarily more adaptive because it allows for greater genetic variation due to genetic recombination; only certain alleles from each parent are passed on, and children aren't exactly like either of the parent. This allows for the evolution of species by means of natural selection.
|What are sequential & synchronous (simultaneous) hermaphroditism?|| Sequential is when an individual starts off as one gender, and then turns into the other gender later in life.|
Synchronous is when an individual has male and female parts at the same time.
|What is gametogenesis?||The formation of gametes. Begins when germ cell multiply by mitosis, resulting in diploid cells.|
|When does meiosis & mitosis occur in gametogenesis?|| Mitosis occurs when germ cells replicate/multiply|
Meiosis occurs when the primary gametophyte splits into secondary gametophytes, and when secondary gametophytes split into gametes.
|What are the 3 major differences between oogenesis & spermatogenesis (other than gender)?|| 1) oogenesis is a discontinuous process (pauses), and spermatogenesis is a continuous process.|
2) Oogenesis produces 1 viable gamete, and spermatogenesis produces 4 viable gametes.
3) In oogenesis, cytokinesis is unequal, and in spermatogenesis, cytokinesis is equal.
|What are the functions of polar bodies?||Polar bodies function to discard the extra haploid sets of chromosomes left over from meiosis.|