What Type Of Reproduction Occurs When Animals Produce Cloned Offspring?

Animal Reproduction and Development

Reproduction Methods

OpenStaxCollege

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Learning Objectives

By the end of this section, you will be able to:

• Describe advantages and disadvantages of asexual and sexual reproduction
• Discuss asexual reproduction methods
• Talk over sexual reproduction methods

Animals produce offspring through asexual and/or sexual reproduction. Both methods have advantages and disadvantages. Asexual reproduction produces offspring that are genetically identical to the parent because the offspring are all clones of the original parent. A unmarried individual can produce offspring asexually and big numbers of offspring can be produced rapidly. In a stable or predictable surroundings, asexual reproduction is an effective ways of reproduction considering all the offspring will be adapted to that environment. In an unstable or unpredictable surroundings asexually-reproducing species may be at a disadvantage considering all the offspring are genetically identical and may not have the genetic variation to survive in new or different weather. On the other manus, the rapid rates of asexual reproduction may allow for a speedy response to environmental changes if individuals have mutations. An boosted advantage of asexual reproduction is that colonization of new habitats may be easier when an individual does not need to find a mate to reproduce.

During sexual reproduction the genetic textile of two individuals is combined to produce genetically various offspring that differ from their parents. The genetic diversity of sexually produced offspring is idea to requite species a amend chance of surviving in an unpredictable or changing environment. Species that reproduce sexually must maintain two dissimilar types of individuals, males and females, which tin limit the ability to colonize new habitats equally both sexes must be present.

Asexual Reproduction

Asexual reproduction occurs in prokaryotic microorganisms (leaner) and in some eukaryotic single-celled and multi-celled organisms. There are a number of means that animals reproduce asexually.

Fission

Fission, besides called binary fission, occurs in prokaryotic microorganisms and in some invertebrate, multi-celled organisms. Later on a period of growth, an organism splits into two divide organisms. Some unicellular eukaryotic organisms undergo binary fission by mitosis. In other organisms, function of the individual separates and forms a second individual. This procedure occurs, for example, in many asteroid echinoderms through splitting of the central disk. Some body of water anemones and some coral polyps ([link]) too reproduce through fission.

Coral polyps reproduce asexually by fission. (credit: G. P. Schmahl, NOAA FGBNMS Manager)

Budding

Budding is a form of asexual reproduction that results from the outgrowth of a part of a cell or body region leading to a separation from the original organism into two individuals. Budding occurs usually in some invertebrate animals such as corals and hydras. In hydras, a bud forms that develops into an adult and breaks away from the main body, as illustrated in [link], whereas in coral budding, the bud does not detach and multiplies as function of a new colony.

Hydra reproduce asexually through budding.

Link to Learning

Watch a video of a hydra budding.

Fragmentation

Fragmentation is the breaking of the body into two parts with subsequent regeneration. If the creature is capable of fragmentation, and the part is big enough, a separate individual will regrow.

For example, in many sea stars, asexual reproduction is accomplished past fragmentation. [link] illustrates a sea star for which an arm of the individual is broken off and regenerates a new ocean star. Fisheries workers have been known to try to kill the ocean stars eating their mollusk or oyster beds by cut them in half and throwing them back into the ocean. Unfortunately for the workers, the two parts tin can each regenerate a new half, resulting in twice as many sea stars to prey upon the oysters and clams. Fragmentation also occurs in annelid worms, turbellarians, and poriferans.

Body of water stars can reproduce through fragmentation. The big arm, a fragment from another ocean star, is developing into a new individual.

Note that in fragmentation, in that location is generally a noticeable difference in the size of the individuals, whereas in fission, two individuals of approximate size are formed.

Parthenogenesis

Parthenogenesis is a grade of asexual reproduction where an egg develops into a complete individual without existence fertilized. The resulting offspring can be either haploid or diploid, depending on the process and the species. Parthenogenesis occurs in invertebrates such as water flees, rotifers, aphids, stick insects, some ants, wasps, and bees. Bees use parthenogenesis to produce haploid males (drones). If eggs are fertilized, diploid females develop, and if the fertilized eggs are fed special diet (so called imperial jelly), a queen is produced.

Some vertebrate animals—such every bit sure reptiles, amphibians, and fish—as well reproduce through parthenogenesis. Although more common in plants, parthenogenesis has been observed in animal species that were segregated by sex in terrestrial or marine zoos. Two female Komodo dragons, a hammerhead shark, and a blacktop shark have produced parthenogenic young when the females have been isolated from males.

Sexual Reproduction

Sexual reproduction is the combination of (unremarkably haploid) reproductive cells from two individuals to form a third (usually diploid) unique offspring. Sexual reproduction produces offspring with novel combinations of genes. This tin can be an adaptive advantage in unstable or unpredictable environments. As humans, we are used to thinking of animals as having two carve up sexes—male and female—adamant at conception. However, in the beast kingdom, there are many variations on this theme.

Hermaphroditism

Hermaphroditism occurs in animals where one private has both male person and female person reproductive parts. Invertebrates such as earthworms, slugs, tapeworms and snails, shown in [link], are often hermaphroditic. Hermaphrodites may cocky-fertilize or may mate with another of their species, fertilizing each other and both producing offspring. Self fertilization is common in animals that have express mobility or are non motile, such as barnacles and clams.

Many snails are hermaphrodites. When two individuals mate, they can produce upward to i hundred eggs each. (credit: Assaf Shtilman)

Sex activity Determination

Mammalian sexual activity determination is determined genetically by the presence of X and Y chromosomes. Individuals homozygous for Ten (20) are female person and heterozygous individuals (XY) are male. The presence of a Y chromosome causes the development of male characteristics and its absence results in female characteristics. The XY organisation is also found in some insects and plants.

Avian sex conclusion is dependent on the presence of Z and Due west chromosomes. Homozygous for Z (ZZ) results in a male and heterozygous (ZW) results in a female. The W appears to be essential in determining the sex of the individual, similar to the Y chromosome in mammals. Some fish, crustaceans, insects (such every bit butterflies and moths), and reptiles use this organization.

The sex activity of some species is non determined by genetics just by some aspect of the environment. Sexual activity determination in some crocodiles and turtles, for instance, is often dependent on the temperature during critical periods of egg development. This is referred to as environmental sex activity determination, or more specifically equally temperature-dependent sex determination. In many turtles, cooler temperatures during egg incubation produce males and warm temperatures produce females. In some crocodiles, moderate temperatures produce males and both warm and cool temperatures produce females. In some species, sex is both genetic- and temperature-dependent.

Individuals of some species change their sexual practice during their lives, alternating betwixt male and female. If the individual is female commencement, it is termed protogyny or "beginning female person," if it is male start, its termed protandry or "first male." Oysters, for case, are born male, abound, and become female and lay eggs; some oyster species change sex multiple times.

Section Summary

Reproduction may be asexual when one individual produces genetically identical offspring, or sexual when the genetic material from two individuals is combined to produce genetically diverse offspring. Asexual reproduction occurs through fission, budding, and fragmentation. Sexual reproduction may mean the joining of sperm and eggs within animals' bodies or information technology may mean the release of sperm and eggs into the environment. An individual may exist one sex, or both; it may start out as one sex and switch during its life, or it may stay male person or female.

Review Questions

Which form of reproduction is thought to be all-time in a stable environment?

1. asexual
2. sexual
3. budding
4. parthenogenesis

A

Which form of reproduction can result from damage to the original animal?

1. asexual
2. fragmentation
3. budding
4. parthenogenesis

B

Which course of reproduction is useful to an animal with little mobility that reproduces sexually?

1. fission
2. budding
3. parthenogenesis
4. hermaphroditism

D

Genetically unique individuals are produced through ________.

1. sexual reproduction
2. parthenogenesis
3. budding
4. fragmentation

A

Free Response

Why is sexual reproduction useful if only half the animals tin produce offspring and 2 separate cells must exist combined to grade a third?

Sexual reproduction produces a new combination of genes in the offspring that may better enable them to survive changes in the surround and assist in the survival of the species.

What determines which sexual activity will result in offspring of birds and mammals?

The presence of the W chromosome in birds determines femaleness and the presence of the Y chromosome in mammals determines maleness. The absenteeism of those chromosomes and the homogeneity of the offspring (ZZ or Twenty) leads to the evolution of the other sex.

Glossary

asexual reproduction

form of reproduction that produces offspring that are genetically identical to the parent

budding

form of asexual reproduction that results from the outgrowth of a role of a cell leading to a separation from the original beast into two individuals

fission

(also, binary fission) method by which multicellular organisms increase in size or asexual reproduction in which a unicellular organism splits into ii separate organisms by mitosis

fragmentation

cutting or fragmenting of the original animal into parts and the growth of a divide beast from each part

hermaphroditism

state of having both male and female reproductive parts inside the same individual

parthenogenesis

course of asexual reproduction where an egg develops into a complete individual without being fertilized

sexual reproduction

mixing of genetic material from two individuals to produce genetically unique offspring

Source: http://pressbooks-dev.oer.hawaii.edu/biology/chapter/reproduction-methods/

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