Fertilization
This forms the extraembryonic hypomere (splanchopleure) that expands to enclose yolk
a. Amnion
b. Yolk sac
c. Chorion
B. Yolk sac
It is the development of an egg in the absence of sperm
Parthenogenesis
In parthenogenesis, doubling of chromosomes is accomplished in the following ways, except:
a. Suppression of 2nd meiotic division
b. Refusion with second polar body
c. Formation of a haploid gamete without chromosome duplication
d. Suppression of 1st meiotic division
C. Formation of a haploid gamete without chromosome duplication
Explanation: This is wrong because it does not restore diploidy—it keeps the cell haploid, so no chromosome doubling happens.
Differentiate oviparous from viviparous reproduction and give examples of organisms in which each occurs.
Oviparous: Egg-laying; occurs in most fishes, amphibians, reptiles, all birds, and monotremes
Viviparous: Live-bearing; occurs in all vertebrates (mostly mammals; eg. humans, dogs, cats)
Give at least three (3) obstacles that must be overcome for successful fertilization:
Sperm and egg must come into proximity
Cell to cell contact must occur
Sperm must penetrate egg cell
Prevention of polyspermy
Metabolic activation of the egg
Completion of meiosis by the egg
Formation and fusion of male and female prouclei leading to the first cleavage division