• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Organisms Sexual and Asexual

Extracts from this document...

Introduction

10 organisms for Asexual reproduction Jelly Fish After fertilization and initial growth, a larval form, called the planula, develops from the egg. The planula larva is small and covered with cilia. It settles onto a firm surface and develops into a polyp. The polyp is cup-shaped with tentacles surrounding a single orifice, perhaps resembling a tiny sea anemone. Once the polyp begins reproducing asexually by budding, it's called a segmenting polyp, or a scyphistoma. New scyphistomae may be produced by budding or new, immature jellies called ephyra may be formed. Many jellyfish can bud off new medusae directly from the medusan stage. Aphids Male and female aphids mate in autumn. Sexual females, but also asexual ones, have two sex chromosomes while sexual males only have one. The aphids may go on reproducing gamogenetically (asexually) ...read more.

Middle

Sea Sponge Asexual reproduction of sponges is through budding or fragmentation, when a small piece of sponge falls off of the main sponge and grows into a new one. Many freshwater sponges form small structures known as gemmules, which function as overwintering devices. Fungus The Ascomycota, commonly known as sac fungi or ascomycetes, form meiotic spores called ascospores, which are enclosed in a special sac-like structure called an ascus. This division includes morels, some mushrooms and truffles, as well as single-celled yeasts and many species that have only been observed undergoing asexual reproduction. Because the products of meiosis are retained within the sac-like ascus, several ascomyctes have been used for elucidating principles of genetics and heredity (e.g. Neurospora crassa). Ascomycota The reproduction of the Ascomycota is very varied and can be either asexual or sexual. ...read more.

Conclusion

Lumbriculus and Aulophorus, for example, are known to reproduce by the body breaking into such fragments. Many other taxa (such as most earthworms) cannot reproduce this way, though they have varying abilities to regrow amputated segments. Sexual reproduction Sexual reproduction allows a species to better adapt to its environment. Some annelida species are hermaphroditic, while others have distinct sexes. Most polychaete worms have separate males and females and external fertilization. The earliest larval stage, which is lost in some groups, is a ciliated trochophore, similar to those found in other phyla. The animal then begins to develop its segments, one after another, until it reaches its adult size. Cnidaria Asexual reproduction via budding is common among cnidaria, particularly among the Hydrozoa class. Asexual larvae bud laterally from the adult polyps, which develop into polyps themselves. The budding is often incomplete, so that colonies of genetically identical polyps physically connected with each other can form. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Variation and Inheritance section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Variation and Inheritance essays

  1. Peer reviewed

    Why is sexual reproduction so common in nature?

    5 star(s)

    Sexual reproduction must enjoy some evolutionary advantage, which means that the advantage is not caused by the process itself, but by the changes it causes in progeny genotypes (as a result of recombination), which should drive the evolution of sex.

  2. Peer reviewed

    Cellular Reproduction

    4 star(s)

    Spores are usually produced by the division of cells within a structure called a sporophagnum. (Harold, 42). Regeneration is a specialized form of reproduction. By regeneration some organisms have the ability to replace an injured or lost appendage. Many plants can grow another entire individual from a small part of

  1. What is population genetics and how is it put to practical use?

    However analysis of allozyme variation is the backbone of modern population genetics, as it provided real data to perform analysis on for genetic variation. The allele frequencies p and q are a very simple description of the amount of genetic variation in a population, and they get less informative and cumbersome as the number of alleles increases.

  2. Analysis of Charles Darwin's Origin of the Species

    A parent does not pass its genetic information and its beneficial variance to only one of its progeny; it passes it to all of them. There fore if it is beneficial to the community of ants to pass along the variation of producing sterile creatures than there is no reason that it should not be.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work