How do different animals reproduce?

Answer 1

This depends on the animal. By 'animal' I am excluding simple organisms that reproduce by dividing.

Slugs, snails and some other invertebrates are hermaphrodites, meaning they have both male and female sex organs. When they mate, they exchange sperm. Each fertilises the other.

More complex organisms are either male or female. The male sex cell, or sperm, must mix with the female sex cell, or ovum, to form an embryo. Corals rely on water to do this for them. They release their eggs and sperm into the water and enough eggs get fertilised to continue the population.

Frogs, some fish and some other organisms practise external fertilisation. The female lays her eggs and the male sprays them with sperm, fertilising most of them.

Most complex animals including some fish, most reptiles, birds and mammals, use internal fertilisation. The male places his sperm inside the female's reproductive tract where they fertilise her egg or eggs. The most common way of doing this is copulation. Basically, the male has a penis or similar organ which he places inside the female to deliver his sperm directly into her reproductive tract.

Answer 2

Animals and humans reproduce by combining haploid cells from each of the two genders, male and female. The female produces an egg cell, and the male a sperm cell. After fertilization, the diploid cells (zygotes) develop either internally (most mammals) or externally in eggs (monotreme mammals, birds, reptiles, fish, and invertebrates).

Answer 3

It happens by sexual reproduction
Animals reproduce in different ways. Some single-celled animals reproduce asexually. They reproduce by simply splitting into two. Animals can also reproduce sexually. Each species has its own reproductive behavior.

Asexual Reproduction

Asexual reproduction involves one parent. As a result, the offspring tend to have the same genotype and phenotype; they lack variation.

It is advantageous in a constant environment because a large number of offspring can be produced in a short time.

Examples:

Flatworms can divide into 2 halves; each half grows into a separate organism.

Cnidarians undergo budding where a new individual grows from and then breaks off of the parent individual.

Echinoderms can be cut to form new individuals.

Insects- parthenogenesis (unfertilized egg develops)

Sexual Reproduction

Sexual reproduction involves the fusion of two gametes.

Sperm and eggs are sometimes produced by the same individual and sometimes produced by different individuals.

The sexes of vertebrates are separate but some vertebrates can change sex and others are both male and female.

Variation

Sexual reproduction promotes variation because offspring inherit genes from two different parents.

In addition, when an individual produces gametes, crossing-over and independent assortment mix genes from that individuals parents. Gametes are haploid; they contain some genes from the individuals mother and some from the father.

Variation is advantageous to species in fluctuating environments.

Reproductive cycles

Reproductive cycles in many vertebrates and invertebrates are related to changes in day length.

Day length is a reliable indicator of season for timing circannual events such as reproductive behavior and migration.

In many species, the pineal gland secretes melatonin in the dark. Increasing day length (decreased melatonin levels) triggers reproductive behavior.

Fertilization

External fertilization

During external fertilization, many gametes are released into the water by each sex at the same time and place.

This type of fertilization requires water because animal sperm must swim to the eggs. Water also protects the gametes from drying out.

Species which have external fertilization are either aquatic or return to water for reproduction.

Internal fertilization

Internal fertilization is practiced by species that lay shelled eggs or have a period of internal embryonic development.

This type of fertilization enables animals to reproduce in a terrestrial environment because it enables sperm to swim to the egg and it prevents gametes from drying out.

The male often has a copulatory organ (a penis) for transferring sperm.

Penis

The penis evolved independently in insects. It is found in all mammals.

Males of some aquatic animals (ex: sharks, skates, rays) have specialized pelvic fins which allow the sperm to be passed to the female.

Some reptiles and birds have a penis but most have a single opening for the reproductive, excretory, and digestive systems called a cloaca.

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Answer 4

Animals either sexually reproduce or asexually reproduce. Animals who sexually reproduce have sex the same way that humans do. Animals that asexually reproduce have sex with themselves. This kind of sex happens inside the body. To learn more, visit Wikipedia.

Answer 5

Different animals reproduce in different ways. The two main forms of reproduction are sexual and asexual with sexual reproduction being common in mammals through conjugation.

Answer 6

Depents on the species, mammals mostly do by extanging body-fluids, but other animals have different breedingrituals.

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Answer 7

Members of the animal kingdom (Animalia) reproduce sexually, meaning the two animals must mate in order to produce offspring.

Answer 8

Animals reproduce by breeding.