Reproduction Of Animals
Reproduction is one of the most characteristic features of living organisms. Life would not exist on Earth if plants and animals did not reproduce to make their offspring. By reproducing, a living organism can be sure that there is another individual of its kind to take its place when it dies. In this way a species of organism guarantees its survival.
All animals produce offspring so their species can continue. Some animals reproduce sexually, by mating with a partner; other reproduce asexually, without mating. Animals grow up in different ways, including by metamorphosis. Care of offspring varies -- some young fend for themselves.
A sea anemone divides to form two individuals. Some insects, such as aphids, can also reproduce asexually, when their unfertilized eggs develop into young.
Animals can be grouped into those which give birth to living offspring and those which lay eggs that eventually hatch into offspring. Those animals which give birth to live offspring are called live-bearing or viviparous. Those animals which lay eggs are called egg-laying or oviparous. The difference is in the place where the offspring develops before it is born.
Some baby animals are miniature copies of their adult relatives, but some look nothing like their parents. They go through an amazing transformation, known as a metamorphosis, before they reach adulthood.
Complete metamorphosis is the change in one step from larva to adult. Moths and butterflies undergo complete metamorphosis. Their caterpillars feed and grow, then enter a resing stage as pupae. Inside the pupal case, the caterpillar transforms into a winged adult. The way tadpoles become frogs is also complete metamorphosis.
How do animals attract mates?
During the breeding season, animals advertise their readiness to mate by using special calls, scents, and other signals. Some animals use elaborate displays or courtship rituals to woo a wary mate. A few creatures, such as earthworms, are hermaphrodite (both male and female), which makes it easier to find a mate.
Why do some animals give birth rather than lay eggs?
Animals born live are more likely to survive than those that hatch out of eggs. While developing inside their mother, babies are at less risk of being eaten than eggs.
Why look after young?
Animals care for offspring to improve their chances of survival. More of these babies survive to adulthood than those whose parents leave them to fend for themselves.
Circle of Life
Life Cycle of butterfly
Life Cycle of Bee
Life Cycle of Ants
Labels: Sexual And Asexual Reproduction