23- speciation Flashcards
what are the four species concepts?
Morphological
Biological
Ecological
Genetic
what is measured in morphological species concept
size, colour, patterns, leg length, etc
what is measured in biological species concept?
Mating calls, rituals, morphology of reproductive organs, colour of dewlap (lizzards)
what is measured in ecological species concept?
the niche or geographical area that individuals occupy
what is measured in genetic species concept?
comparing DNA sequences
strengths of morphological species concepts
-easy to use
-can be used for fossils
can be used for both sexual and asexual species
what are weaknesses for morphological species concepts
-individuals from two different species may look very similar
-individuals from two different populations may look quite different
strengths of biological species concepts
-often reliable
-can be tested buy studying mating calls, colours, pollination
weaknesses of biological species concepts
-cannot be used for fossils or asexual species
-many population ranges do not overlap so we cannot say if they can breed or not
-some species form hybrids
strengths of ecological species concepts
-easy to use, i.e. record the niche or area
weaknesses of ecological species concepts
-many different species live in the same areas (relate or not)
-some species possess large phenotypic plasticity and can grow under a variety of conditions, habitats and geographic areas
strengths of genetic species concepts
-can be used for a wide variety of organisms, i.e. sexual and asexual, fossils, etc.
-genetic differences can be analyzed by comparing DNA sequences
weaknesses of genetic species concepts
-DNA analysis cannot always be performed, cannot be performed in the field
-it may be difficult to determine how similar DNA sequences would have to be for two individuals to belong to one species
which species concept is most useful in the field?
Morphological
is it more likely that many species on an island resulted from many species from the mainland or just a few?
just a few species from mainland result in many species on the island
will a geographical barrier or change in habitat (eg. road, river, forest fire) reproductively isolate populations?
it depends on the species and how long the barrier existed for ex. may stop beetles but not birds. over time, speciation happens if populations don’t cross often.
what is allopatric speciation?
speciation due to geographical barriers such as mountains, rivers, roads
what is separation of populations by physical stuctures called?
vicariance
what does dispersal lead to?
allopatric speciation, new species would likely arise from those that dispersed from the mainland
