Origin and Diversification of Species Flashcards
What is the biological definition of a species?
one or more populations whose members can potentially interbreed and produce fertile offspring - reproductive isolation between species
Which species definition is the least useful for classifying prokaryotes and why?
biological (cause they don’t interbreed)
How are species classified morphologically?
differ in appearance (shape, structures)
How are species classified ecologically?
have different ecological niches
When might morphological classification of species be useful and why?
classifying species - can’t observe their behaviour
When might ecological classification of species be useful?
studies at the ecosystem or large community scale
How are species classified phylogenticly?
genetic similarities
What species concept is useful for classifying organisms that reproduce by cloning?
phylogenetic
What are some reproductive barriers?
habitat isolation, temporal isolation, behavioural isolation, mechanical isolation, gametic isolation, reduced viability,, reduced fertility, hybrid breakdown
If there are no reproductive barriers between two species, what happens?
they produce viable, fertile offspring - hybrids just as fit as the original species
What reproductive barriers prevent a mating attempt?
habitat isolation, temporal isolation, behavioural isolation
What reproductive bariers allow a mating attempt but prevent fertilization?
mechanical isolation and gametic isolation
What reproductive barriers allow fertilization but prevent the production of viable, fertile offspring?
reduced viability, reduced fertility, and hybrid berakdown
What is habitat isolation and how does it prevent reproduction?
two species occupy different areas - even though they’re not isolated by obvious physical barriers, they may rarely encounter each other
What keeps species distinct?
reproductive barriers
What is temporal isolation and how does it prevent reproduction?
live in same habitat, but breed during different times (of day, season, or year) - can’t mix their gametes
If two species live in the same habitat, what is the next reproductive barrier to stop them from reproducing?
temporal isolation
What is behavioural isolation and how does it prevent reproduction?
species-specific courtship behaviours attracting mates may be different between two species - meant to identify potential mates of same species
What is mechanical isolation and how does it prevent reproduction?
mating can be attempted, but morphological differences prevent its successful completion (i.e. sex organs don’t fit together)
What is gametic isolation and how does it prevent reproduction?
sperm of one species may not be able to fertilize eggs of another (due to no survival or other biochemical mechanisms preventing penetration of egg membrane) - no fertilization, no baby
What are the prezygotic barriers?
habitat, temporal, behavioural, mechanical, and gametic isolation
What do prezygotic barriers do?
impede mating or hinder fertilizaiton if mating does occur
What are the postzygotic barriers?
reduced hybrid viability, reduced hybrid fertility, hybrid breakdown
What do postzygotic barriers do?
prevent a hybrid zygote from developing into a viable, fertile cell
