Which Example Represents a Disadvantage of Asexual Reproduction

Which Example Represents a Disadvantage of Asexual Reproduction.

Chapter 24. Animal Reproduction and Development

24.1. Reproduction Methods

Learning Objectives

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

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


Animals produce offspring through asexual and/or sexual reproduction. Both methods take advantages and disadvantages.
Asexual reproduction
produces offspring that are genetically identical to the parent considering the offspring are all clones of the original parent. A single private can produce offspring asexually and large numbers of offspring can be produced quickly. In a stable or predictable environment, asexual reproduction is an effective means of reproduction because all the offspring will be adapted to that surroundings. In an unstable or unpredictable environment asexually-reproducing species may be at a disadvantage because all the offspring are genetically identical and may non accept the genetic variation to survive in new or unlike weather. On the other paw, the rapid rates of asexual reproduction may let for a speedy response to environmental changes if individuals accept mutations. An additional reward 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 material of two individuals is combined to produce genetically diverse offspring that differ from their parents. The genetic diverseness of sexually produced offspring is thought to give species a better gamble of surviving in an unpredictable or changing environment. Species that reproduce sexually must maintain two dissimilar types of individuals, males and females, which can limit the ability to colonize new habitats as both sexes must be nowadays.


Asexual Reproduction


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


Fission





Fission, also called binary fission, occurs in prokaryotic microorganisms and in some invertebrate, multi-celled organisms. After a flow of growth, an organism splits into ii split organisms. Some unicellular eukaryotic organisms undergo binary fission by mitosis. In other organisms, part of the private separates and forms a second individual. This process occurs, for example, in many asteroid echinoderms through splitting of the primal disk. Some sea anemones and some coral polyps (Figure 24.two) as well reproduce through fission.

Figure_43_01_01
Figure 24.2.  Coral polyps reproduce asexually past fission. (credit: M. P. Schmahl, NOAA FGBNMS Manager)


Budding





Budding
is a class of asexual reproduction that results from the outgrowth of a office of a cell or body region leading to a separation from the original organism into 2 individuals. Budding occurs normally in some invertebrate animals such equally corals and hydras. In hydras, a bud forms that develops into an adult and breaks away from the main trunk, every bit illustrated in Figure 24.3, whereas in coral budding, the bud does not detach and multiplies equally office of a new colony.

Figure_43_01_02
Figure 24.three.  Hydra reproduce asexually through budding.


Spotter a video of a hydra budding.


Fragmentation





Fragmentation
is the breaking of the body into two parts with subsequent regeneration. If the animal is capable of fragmentation, and the role is big enough, a split up individual will regrow.


For example, in many ocean stars, asexual reproduction is achieved by fragmentation. Figure 24.4 illustrates a body of water star for which an arm of the private is cleaved off and regenerates a new sea star. Fisheries workers have been known to try to kill the sea stars eating their mollusk or oyster beds by cut them in half and throwing them back into the bounding main. Unfortunately for the workers, the ii parts can each regenerate a new half, resulting in twice as many body of water stars to casualty upon the oysters and clams. Fragmentation also occurs in annelid worms, turbellarians, and poriferans.

Basic CMYK
Figure 24.four.  Sea stars can reproduce through fragmentation. The large arm, a fragment from another bounding main star, is developing into a new individual.


Note that in fragmentation, at that place is by and large 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 beingness fertilized. The resulting offspring can be either haploid or diploid, depending on the process and the species. Parthenogenesis occurs in invertebrates such equally h2o flees, rotifers, aphids, stick insects, some ants, wasps, and bees. Bees use parthenogenesis to produce haploid males (drones) and diploid females (workers). If an egg is fertilized, a queen is produced. The queen bee controls the reproduction of the hive bees to regulate the blazon of bee produced.


Some vertebrate animals—such every bit certain reptiles, amphibians, and fish—likewise reproduce through parthenogenesis. Although more than mutual in plants, parthenogenesis has been observed in animal species that were segregated by sexual practice 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 (usually haploid) reproductive cells from 2 individuals to form a 3rd (unremarkably 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 separate sexes—male and female—determined at conception. However, in the fauna kingdom, at that place are many variations on this theme.


Hermaphroditism





Hermaphroditism
occurs in animals where one individual has both male person and female reproductive parts. Invertebrates such every bit earthworms, slugs, tapeworms and snails, shown in Figure 24.5, are ofttimes hermaphroditic. Hermaphrodites may self-fertilize or may mate with another of their species, fertilizing each other and both producing offspring. Self fertilization is mutual in animals that accept limited mobility or are not motile, such as barnacles and clams.

DCF 1.0
Figure 24.5.  Many snails are hermaphrodites. When two individuals mate, they tin can produce up to i hundred eggs each. (credit: Assaf Shtilman)


Sex Determination


Mammalian sex decision is determined genetically past the presence of X and Y chromosomes. Individuals homozygous for X (XX) are female 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 system is also found in some insects and plants.


Avian sex determination is dependent on the presence of Z and Westward chromosomes. Homozygous for Z (ZZ) results in a male person and heterozygous (ZW) results in a female. The W appears to be essential in determining the sex activity of the private, like to the Y chromosome in mammals. Some fish, crustaceans, insects (such as butterflies and moths), and reptiles use this system.


The sex of some species is not determined by genetics but by some aspect of the environment. Sex determination in some crocodiles and turtles, for instance, is often dependent on the temperature during critical periods of egg evolution. This is referred to as ecology sex decision, or more than specifically as temperature-dependent sex activity determination. In many turtles, libation 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 activity is both genetic- and temperature-dependent.


Individuals of some species change their sex during their lives, alternate between male and female. If the individual is female commencement, it is termed protogyny or “kickoff female,” if it is male outset, its termed protandry or “outset male.” Oysters, for case, are built-in male, grow, and become female and lay eggs; some oyster species change sex activity multiple times.

Summary

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

Exercises

  1. Which form of reproduction is thought to be best in a stable environment?
    1. asexual
    2. sexual
    3. budding
    4. parthenogenesis

  2. Which form of reproduction tin can upshot from damage to the original brute?

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

  3. Which form of reproduction is useful to an animal with petty mobility that reproduces sexually?

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

  4. Genetically unique individuals are produced through ________.

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

  5. Why is sexual reproduction useful if only half the animals can produce offspring and ii separate cells must be combined to form a tertiary?

  6. What determines which sex activity will event in offspring of birds and mammals?

Answers

  1. A
  2. B
  3. D
  4. A
  5. Sexual reproduction produces a new combination of genes in the offspring that may better enable them to survive changes in the environment and assist in the survival of the species.
  6. The presence of the W chromosome in birds determines femaleness and the presence of the Y chromosome in mammals determines maleness. The absence of those chromosomes and the homogeneity of the offspring (ZZ or XX) leads to the development of the other sex activity.

Glossary

asexual reproduction
form of reproduction that produces offspring that are genetically identical to the parent
budding
course of asexual reproduction that results from the outgrowth of a office of a prison cell leading to a separation from the original animal into two individuals
fission
(also, binary fission) method by which multicellular organisms increment in size or asexual reproduction in which a unicellular organism splits into ii carve up organisms by mitosis
fragmentation
cutting or fragmenting of the original animal into parts and the growth of a separate animal from each part
hermaphroditism
state of having both male person and female reproductive parts within the same individual
parthenogenesis
form of asexual reproduction where an egg develops into a complete individual without beingness fertilized
sexual reproduction
mixing of genetic material from ii individuals to produce genetically unique offspring

Which Example Represents a Disadvantage of Asexual Reproduction

Source: https://opentextbc.ca/biology/chapter/24-1-reproduction-methods/