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Genetically unique individuals are produced through _.Which form of reproduction is useful to an animal with little mobility that reproduces sexually?.

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

Which form of reproduction is thought to be best in a stable environment?.

An individual may be one sex, or both it may start out as one sex and switch during its life, or it may stay male or female. Sexual reproduction may mean the joining of sperm and eggs within animals’ bodies or it may mean the release of sperm and eggs into the environment. Asexual reproduction occurs through fission, budding, and fragmentation. 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. If the individual is female first, it is termed protogyny or “first female,” if it is male first, its termed protandry or “first male.” Oysters, for example, are born male, grow, and become female and lay eggs some oyster species change sex multiple times. Individuals of some species change their sex during their lives, alternating between male and female. In some species, sex is both genetic- and temperature-dependent. In some crocodiles, moderate temperatures produce males and both warm and cool temperatures produce females. In many turtles, cooler temperatures during egg incubation produce males and warm temperatures produce females. This is referred to as environmental sex determination, or more specifically as temperature-dependent sex determination. Sex determination in some crocodiles and turtles, for example, is often dependent on the temperature during critical periods of egg development.

The sex of some species is not determined by genetics but by some aspect of the environment. Some fish, crustaceans, insects (such as butterflies and moths), and reptiles use this system. The W appears to be essential in determining the sex of the individual, similar to the Y chromosome in mammals. Homozygous for Z (ZZ) results in a male and heterozygous (ZW) results in a female. The XY system is also found in some insects and plants.Īvian sex determination is dependent on the presence of Z and W chromosomes. The presence of a Y chromosome causes the development of male characteristics and its absence results in female characteristics. Individuals homozygous for X (XX) are female and heterozygous individuals (XY) are male.

Mammalian sex determination is determined genetically by the presence of X and Y chromosomes. Species that reproduce sexually must maintain two different types of individuals, males and females, which can limit the ability to colonize new habitats as both sexes must be present. The genetic diversity of sexually produced offspring is thought to give species a better chance of surviving in an unpredictable or changing environment. An additional 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.ĭuring sexual reproduction the genetic material of two individuals is combined to produce genetically diverse offspring that differ from their parents. On the other hand, the rapid rates of asexual reproduction may allow for a speedy response to environmental changes if individuals have mutations.

In an unstable or unpredictable environment asexually-reproducing species may be at a disadvantage because all the offspring are genetically identical and may not have the genetic variation to survive in new or different conditions. In a stable or predictable environment, asexual reproduction is an effective means of reproduction because all the offspring will be adapted to that environment. A single individual can produce offspring asexually and large numbers of offspring can be produced quickly. Asexual reproduction produces offspring that are genetically identical to the parent because the offspring are all clones of the original parent. Both methods have advantages and disadvantages.

Describe advantages and disadvantages of asexual and sexual reproductionĪnimals produce offspring through asexual and/or sexual reproduction.