Question

Which of the following organisms can produce female offspring through parthenogenesis? a. cnidarians b. flukes c. choanocytes e. annelids d. rotifers

Short answer

The organism that can produce female offspring through parthenogenesis among the given options is rotifers.

Step-by-step solution

Define Parthenogenesis

Parthenogenesis is a type of asexual reproduction where the growth and development of embryos occur without fertilization. In this process, females produce offspring without the need for males.

Know the Organisms

It is essential to know what these organisms are. Cnidarians are a group of aquatic, mostly marine, species. Flukes are parasitic flatworms. Choanocytes are cells that line the interior of the chambers of a sponge. Annelids are a large phylum of segmented worms, while Rotifers are tiny aquatic animals.

Identify the Organism

Among the given choices, Rotifers are known for using parthenogenesis as a form of reproduction, especially in environments where males are scarce or absent.

Key concepts

Asexual Reproduction

Asexual reproduction is a fascinating process where a single organism can reproduce without the need for genetic material from another individual. This method of reproduction is widespread in the animal kingdom and stands in contrast to sexual reproduction, where two parents contribute genetic material to produce offspring. Asexual reproduction occurs through various mechanisms, such as binary fission, budding, and parthenogenesis.

Parthenogenesis, in particular, is a unique form of asexual reproduction where an embryo is developed from an unfertilized egg cell. An intriguing aspect of parthenogenesis is that it enables female organisms to produce offspring on their own, essentially generating a clone of themselves. This phenomenon occurs in several species, including plants, insects, and some vertebrates. The advantages of asexual reproduction include the ability to reproduce rapidly and efficiently in stable environments where adapting to changing conditions is not necessary.

Embryo Development

Embryo development is a critical phase in the life cycle of an organism, where a single cell, the zygote, goes through a series of transformations to become a fully formed individual. However, in the context of parthenogenesis, the process diverges somewhat from the usual sexual reproduction. Since there is no fertilization, the embryo develops from an egg that has not undergone the typical fusion of genetic material from two parent cells.

In parthenogenesis, an egg cell can be stimulated to develop into an embryo through various triggers, which may be environmental or internal. The resultant embryo then grows and differentiates through cell division and specialization, following similar stages as those seen in sexually reproduced embryos. The developmental process is ultimately guided by the organism's genetic code, allowing for a fully functional animal to emerge, complete with all necessary structures and systems for survival.

Rotifers

Rotifers are microscopically small, multicellular organisms that play a crucial role in freshwater ecosystems. Despite their tiny size, rotifers have astonishingly complex anatomy, including a complete digestive tract and a unique corona of cilia at their head, which they use for locomotion and feeding.

Rorifers are particularly notable for their reproductive strategies, which vary between species. Many rotifers can reproduce through parthenogenesis, especially when environmental conditions are stable and favorable. In some cases, males are absent from the population altogether. The ability of rotifers to reproduce asexually allows for rapid population growth and colonization of new habitats. When conditions are harsh or uncertain, some rotifers can produce males, or engage in sexual reproduction, leading to the creation of durable, desiccation-resistant eggs. These strategies enable rotifers to adapt and survive in changing environments.