Akamia
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I'm studying for a test on the natural sciences – a step toward an end goal of a degree in computer science – and the textbook I'm studying from had two statements that appear to conflict with each other.
In the former statement, it appears to be saying that different species can successfully interbreed – with the caveat that the species are related – but the wording of the latter does not appear to allow for that.
Is it an oversight on the textbook editor's part, or am I missing something huge?
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REA CLEP Natural Sciences p. 19 said:Genetic drift occurs within finite separated populations, allowing that population to develop its own distinct gene pool. However, occasionally an individual from an adjacent population of the same species may immigrate and breed with a member of the previously locally isolated group. The introduction of new genes from the immigrant results in a change of the gene pool, known as gene migration . Gene migration is also occasionally successful between members of different, but related species. The resultant hybrids succeed in adding increased variability to the gene pool.
REA CLEP Natural Sciences p. 20 said:In order for a new species to develop, substantial genetic changes must occur between populations, which prohibit them from interbreeding. These genetic changes may result from genetic drift or from mutation that take place separately in the two populations. Allopatric speciation occurs when two populations are geographically isolated from each other. For instance, a population of squirrels may be geographically separated by a catastrophic event such as a volcanic eruption. Two populations (separated by the volcanic flow) continue to reproduce and experience genetic drift and/or mutation over time. This limits each population’s gene pool and produces changes in expressed traits. Later, the geographical separation may be eliminated as the volcanic flow subsides; even so, the two populations have now experienced too much change to allow them to successfully interbreed again. The result is the production of two separate species.
In the former statement, it appears to be saying that different species can successfully interbreed – with the caveat that the species are related – but the wording of the latter does not appear to allow for that.
Is it an oversight on the textbook editor's part, or am I missing something huge?
Sent from my iPad using Tapatalk Pro