Science #18
Most fish, amphibians, and reptiles lay eggs that mature outside the body. Birds and a few mammals also lay eggs that mature outside the body. Most mammals produce eggs and embryos that mature inside the mother. The eggs of fish and amphibians have a jelly-like outer layer. The eggs of birds and reptiles have a harder, protective outer layer.
How are the eggs of animals alike? How are they different?
The shell keeps the embryo from drying out. The yolk provides food for the developing embryo.
How does a bird's egg protect the embryo developing inside?
Amphibians go through metamorphosis, but other vertebrates do not.
How does an amphibian's life cycle differ from that of other vertebrates?
By a jelly-like layer that surrounds the egg.
How is a fish or amphibian egg protected?
egg, larva, pupa, adult
In complete metamorphosis, the animal goes through four distinct phases: ______
egg, nymph, adult.
In incomplete metamorphosis the animal goes through three stages gradually: _____
larva
In the life cycle of a butterfly, what stage is the caterpillar?
It is easier to tell whether a frog is an adult because a frog has distinct stages of life. If it still has a tail or does not have legs, it is not an adult yet. A crow has the same physical features as it grows, so it is difficult to tell when the crow is an adult.
Is it easier to tell whether a frog is an adult or whether a crow is an adult? Explain.
herbivores or plant eaters
Most tadpoles are ____ eaters
butterflies, moths, flies, and beetles
Name some animals that go through complete metamorphosis:
grasshoppers, termites, and bedbugs
Some insect species, including ______ go through incomplete metamorphosis.
gills and tails emerge from eggs completely aquatic
Tadpoles with _______ . They are _____ for the first parts of their lives.
adults and move onto land. There they breathe air and have a carnivorous, or meat eating diet.
The froglets eventually become ______
egg, tadpole, froglet, adult the adults reproduce, and new eggs are laid. This starts the cycle over.
The life cycle of a frog is ____. It is a cycle, because _____
Although it seems quiet, the organism inside the cocoon is very active. The entire body is changing. For example, in the pupa stage, a caterpillar is changing into a butterfly with the appearance of wings, different mouth parts, new muscles, and new legs. When the cocoon opens, an adult butterfly with a completely restructured body emerges.
The pupa is often thought to be a resting stage. Why is this incorrect?
larva
an immature stage in complete metamorphosis where the organism does not resemble the adult
nymph
A __ is similar to an adult form, but it is smaller and lacks wings and reproductive structures.
their structures and the environments in which they live.
Animals have different eggs depending on ____
lose their tails and start to develop legs and lungs, becoming a froglet.
As tadpoles grow, they gradually _______
In incomplete metamorphosis, the nymph stage is the same as the larva stage in complete metamorphosis, and the pupa stage is skipped.
What metamorphosis stage is skipped in incomplete metamorphosis? Explain.
Grasshoppers have an exoskeleton. This does not increase in size as they grow. They must shed their hard, outer skeletons to make room for a larger body size. Grasshoppers go through five separate shedding stages before they reach adulthood.
Why can't grasshoppers grow gradually like mammals, reptiles, and birds do?
Monotremes live young.
____ are the only mammals that lay eggs. All other mammals give birth to _____
pupa
a nonfeeding stage in complete metamorphosis in which a hard, caselike cocoon surrounds the organism
Metamorphosis
a series of distinct growth stages in an animal's life cycle that are different from one another
Complete Metamorphosis
a series of four distinct growth stages in an animal's life cycle
nymph
a stage of metamorphosis where the organism is similar to an adult form but is smaller
nymph
grasshoppers take on the _____ body form after hatching from eggs.
incomplete metamorphosis
in an animal's life cycle, a series of three growth stages that occur gradually
