lec 30- coevolution 2 Flashcards
(28 cards)
coevolution between two species is mediated by what?
reciprocal selection
what is reciprocal selection?
when traits are selected for or against due to their interaction with another species
what is an example of reciprocal selection?
orchid have evolved colours, patterns, and odours that mimic wasps and bees that attempt mating, and transfer pollen masses
how did red crossbills coevolve with pinecones?
the Red crossbills evolved unique beaks used to open pinecones to get to the seeds
how is the red crossbills an example of diversifying coevolution?
pinecones can have different sizes and thicknesses of cone scales, as such the beaks of red crossbills vary heavily
when is it easiest to open pinecones?
when dry because when they are wet, they are closed
what can diversifying coevolution accelerate?
divergence between populations
is more beak depth needed for thicker seed cone scales?
yes
what happened to pinecones when squirrels that can open any cone size or thickness arrived?
they select for more seeds rather than thicker scales in pines
how have flowering plants and ants coevolved?
flowering plants have developed special proteins and oil rich bodies (elaisosomes) on their seeds that are dispersed by ants, they are carried back to the nest and the elaisosomes are eaten while the seeds are not, resulting in their protection and eventual growth
can hosts and parasites undergo cospeciation?
yes
e.g. ancestral gopher and ancestral lice evolve separately into 4 species together
can extinction of one mutualistic species have a negative effect on the other coevolved species?
yes, extinction of NZ tui birds cause low fruiting success in coevolved plant
has the extinction of the Moa in NZ resulted in vegetation structure and dispersal of seed changes?
yes
what is endosymbiosis?
when a mutualistic organism lives inside another, it is necessary for survival
how are humans an example of endosymbiosis?
the gut contains many bacteria needed for humans to survive, they bacteria in the gut is needed to make vitamins
is the evolution of mitochondria and chloroplasts in eukaryotes an example of endosymbiosis?
yes
give an example of rapid endosymbiosis:
coral incorporate living algae in tissues as symbionts
how did the solar powered sea slug end up the way it did?
it took in chloroplast from its food source
what did Dr. Lynn Margulis propose?
that the mitochondria, the photosynthetic plastids, and the (9+2) basal bodies of flagella were once free living prokaryotic cells
what is mitochondria derived from?
former free living aerobic marine bacteria
what is SAR 11?
a very abundant clade of marine bacteria, all aerobic and some early species became endosymbiotic after phagocytosis by a eukaryote cell
what is the origin of the Mitochondria’s double membrane?
phagocytosis brought vesicle with marine bacteria in, vesicle membrane is outer mitochondrial membrane while bacteria membrane is inner membrane
are all plant plastids (double membrane organelles) derived from endosymbiosis?
yes
were chloroplasts also phagocytosed and ended up being in an endosymbiotic relationship with plant cells?
yes
