Vocabulary
external fertilization
a type of sexual reproduction in which the sperm and egg unite outside the parents’ bodies
What happens in fertilization?
A sperm (from the male organism) unites with a gamete called the egg (from the female organism).
internal fertilization
a type of sexual reproduction in which the sperm and egg unite inside the female’s body
Why can external fertilization happen in the water?
External fertilization happens in the water because the sperm must be able to swim to the eggs.
Nymph
An immature form of an insect that does not change greatly
Why do many animals that practice external fertilization lay hundreds (or even thousands) of eggs?
Because the eggs are vulnerable and unable to defend themselves, animals that practice external fertilization often produce hundreds or thousands of eggs in order to guarantee survival for at least some.
Complete metamorphosis
A change in anatomical form through a series of life stages. Complete metamorphosis has four stages - egg, larva, pupa, and adult.
Why must certain invertebrates (like grasshoppers) shed their exoskeletons?
Because their exoskeleton isn't living (and doesn't grow with the insect), certain invertebrates (like grasshoppers) must get rid of their exoskeleton to continue growing.
Incomplete metamorphosis
A change in anatomical and physiological form through a series of life stage, but with only three stages. The three stages are egg, nymph, and adult.
Give one similarity and one difference between complete and incomplete metamorphosis.
Similarity
1. Both start with the "egg" stage.
2. Both involve physical changes until they have reached the adult stage.
3. Many kinds of insects use incomplete or complete metamorphosis.
Differences
1. Complete metamorphosis has four stages while incomplete has three.
2. Complete metamorphosis has the larva and pupa stage, while incomplete metamorphosis have the nymph stage.
3. Complete metamorphosis has more intense changes while incomplete metamorphosis involves more gradual changes.