Biosci 210 Exam Questions With Correct Answers!!

Biological species concepy - Answer-Biological species concept (BSC) defines a species as a reproductive community and is thus based on interbreeding as a criterion. "Groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups. The BSC has dominated biology since 1940s. Problems with the BSC - Answer-Plants are problematic because of interspecific hybridization between clearly different species; doesnt apply to asexual orgnaisms and those land plants that self polinate. Inapplicable in practice. Breeding experiments are impractical in many cases because of the number of populations involved or difficulties with captive breeding. Breeding experiments can often be inconclusive - cant always duplicate natural conditions of breeding. So failure to breed doesnt mean the organisms cant or dont interbreed in the wild (pandas) Genetic cluster or phenotypic cohesion - Answer-Genetic cluster or phenotypic cohesion: this group of concepts includes reconviction species concept and is based on the notion that species form units that are discrete or cohesive in terms of reproduction or gene flow. Ecological and evolutionary species concepts: - Answer-Ecological and evolutionary species concepts: these concepts are based on eco and evo distinctiveness respectively. The former is based on the concept of ecological niche while the latter is defined as a lineage that maintains its identity and has its own distinctive evolutionary history. Phylogenetic species concepts - Answer-Phylogenetic species concepts: these are all based on the principle of shared evolutionary history but differ in the details of how this is defined. Some are based on the criterion of monophyly while others are defined on the basis of shared, derived characters (synapomorphies). The differential species concept. DFSC - Answer-This concept defines species as "groups of individuals that are reciprocally characterized by features that would have negative fitness effects on other groups and that cannot be regularly exchanged between groups upon contact. This concept differs from the BSC by considering that transmission of species-species characters between populations is not only restricted by reproductive isolation but also by divergent natural selection. The DFSC is thus concerned with adaptation; features may be adaptive for one population but manadaptive for another population. Thus this concept does not require complete reproductive isolation for populations to be considered species, but allows for the exchange of features including neutral geneswith other populations except for those that are causing the differentiation. The DFSC is considered to be highly relevant to conservation, as it recognises populations that differ in terms of local adaptation but nonetheless can exchange genes with other populations.