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7.5 Reading #1:
 Reproduction Methods 
Animals can reproduce sexually or asexually to produce offspring. Both approaches have 
benefits and drawbacks. 
Asexual reproduction
creates clones of the original parent, which results in 
offspring that are genetically identical to the parent. Asexual reproduction allows for the rapid 
production of large numbers of offspring by a single individual. Asexual reproduction is a successful 
method of reproduction in a stable or predictable environment because all the offspring will be 
adapted to that environment. 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. On the other hand, if individuals have 
mutations, the quick rates of asexual reproduction might allow for a quick response to environmental 
changes. Another benefit of asexual reproduction is that it may make it simpler to colonize new 
habitats because an individual does not need to find a mate in order to reproduce. 
During 
sexual reproduction
the genetic material of two individuals is combined to produce 
genetically diverse offspring that differ from their parents. It is believed that the genetic diversity of 
sexually reproduced offspring increases a species' likelihood of enduring in an unstable or changing 
environment. The requirement for maintaining two distinct types of individuals, males and females, 
in sexually reproducing species can restrict their capacity to colonize new habitats. 

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Asexual Reproduction 
Prokaryotic microorganisms (bacteria) and some eukaryotic single- and multi-celled 
organisms are capable of asexual reproduction. Animals can reproduce in a variety of asexual ways. 
Fission
Prokaryotic microorganisms and some invertebrate, multicellular organisms experience 
fission, also known as binary fission. An organism divides into two distinct organisms following a 
period of growth. Some eukaryotic unicellular organisms divide in binary by going through mitosis. 
Other organisms have the ability to split into two separate individuals. The central disk is split during 
this process in many asteroid echinoderms, for instance. Some sea anemones and some coral polyps 
(Figure 153) also reproduce through fission.