Life Cycles, Insect, Frog
Vocabulary
Life Cycles, Insect, Frog
Insects – Metamorphosis- invertebrate - Metamorphosis refers to the way that insects develop, grow, and change form. Metamorphosis actually means "change". There are two types of metamorphosis--incomplete and complete.
Incomplete Metamorphosis: About 12% of all insects go through incomplete metamorphosis. Incomplete metamorphosis has 3 stages.
Egg - A female insect lays eggs. These eggs are often covered by an egg case which protects the eggs and holds them together.
Nymph - The eggs hatch into nymphs. Nymphs’ looks like small adults, but usually don't have wings. Insect nymphs eat the same food that the adult insect eats. Nymphs shed or molt their exoskeletons (outer casings made up of a hard substance called chitin) and replace them with larger ones several times as they grow. Most nymphs molt 4-8 times.
Adult - The insects stop molting when they reach their adult size. By this time, they have also grown wings.
Complete Metamorphosis: About 88% of all insects go through complete metamorphosis. Complete metamorphosis has 4 stages:
Egg - A female insects lays eggs.
Larva - Larvae hatch from the eggs. They do not look like adult insects. They usually have a worm-like shape. - Caterpillars, maggots, and grubs are all just the larval stages of insects. Larvae molt their skin several times and they grow slightly larger.
Pupa - Larvae make cocoons around themselves. Larvae don't eat while they're inside their cocoons. Their bodies develop into an adult shape with wings, legs, internal organs, etc. This change takes anywhere from 4 days to many months.
Adult - Inside the cocoon, the larvae change into adults. After a period of time, the adult breaks out of the cocoon.
Frog Metamorphosis- Vertebrate
The Egg - Frogs lay their eggs in water or wet places. A floating clump of eggs is called frog spawn.
Description of change:
The large and slippery mass of eggs is too big to be eaten. This is nature's way of protecting them.
Smaller clumps of eggs will be eaten by the creatures living near or in the pond.
- Egg Development:
The egg begins as a single cell.
Several thousandare sometimes laid at once. It becomes surrounded by a jellylike covering, which protects the egg.
The egg slowly develops. But, only a few develop into adults. Ducks, fish, insects, and other water creatures eat the eggs.
The Cell Splits
- The single cell in the egg eventually splits into two. These two split making four cells, and so on. Eventually, there are many cells in the egg.
2.The Embryo
The mass of cells in the egg come to form an embryo.
Organs and gills begin to form, and in the meantime, the embryo lives off of its internal yolk. This supplies it with nutrients for 21 days.
3.The Tadpole
- After its 21 day development period, the embryo leaves its jelly shell, and attaches itself to a weed in the water.
- This quickly becomes a tadpole, a baby frog. The tadpoles grow until they are big enough to break free into the water. This can take from 3 days to 3 weeks, depending on what kind of frog they will become.
- They eat very small plants that stick to larger plants in the water. These tiny plants are called algae. The tadpole has a long tail, and lives in the water.
- The tadpole has a long tail, and lives in the water.
4.Changes in tadpoles - tadpolebeginsto Change
- After about five weeks, the tadpole begins to change. It starts to grow hind legs, which are soon followed with forelegs.
- Behind their heads bulges appear where their front legs are growing. Their tails become smaller.
- Lungs begin to develop, preparing the frog for its life on land. Now and then, they wiggle to the surface to breathe in air.
- The tail becomes larger and makes it now possible for the tadpole to swim around and catch food.
- They eat plants and decaying animal matter. Some tadpoles eat frogs’ eggs and other tadpoles.
- Over time, the tadpole becomes even more froglike. They have shed their skin and lip. The tail becomes much smaller, and the legs grow. The lungs are almost functioning at this point.Now a frog.