Lecture 18: Evolution and conservation Flashcards
human activities change the environment;
- habitat loss (forced move,adapt or die out)
- climate change (or rainfall impact will affect the suitability of habitat for different species)
- pollution (degrade habitats and reduce their suitability)
Consequences of change:
- reduced population sizes
- extinction of populations
- extinction of species
- loss of ecosystem
dodo extinction date
1681
great auk extinction
hunted, eggs were removed and consumed as food, became rare museums and collectors were keen to have one
chinese river dolphin extinction :
extinct in 2006, due to overfishing and pollution
looking at historical extinction and current extinction what can you tell
introduced species use to be most devastating, then habitat loss then human exploitation.
NOW; habitat loss, intro species, human exploitation
all species are the outcome of
evolution
correlates of extinction questions to consider
- Are some species more likely to become extinct than others?
- Are species at threat randomly distributed?
- Does this depend on their ecology?
- Does this depend on where they live?
Phylogenetic niche conservatism
- species inherit their niches from their ancestors.
- so new species are v similar to parent species - DO THEY SHARE SIMILAR CHANCES OF EXTINCTION?
- share similar life histories
niche:
the way in which an organism fits into an ecological community or ecosystem
e.g. of phylogenetic niche conservatism:
- Old world leaf warblers
- Very similar in appearance
- Also similar in ecology
- Insectivorous
- Feed on trees
- Short-lived
- Many co-occur
Consequences of phylogenetic niche conservatism
- Closely related species share similar levels of threat, because they are ecologically similar
- Low rates of adaptability: conservatism is a consequence of this
- Low rates of evolution: also conservatism results from this
IUCN threat;
measure of how likely populations are to become extinct in coming years
(extinct, endangered etc.)
-Life history & ecological variables
-Chosen carefully
-Used statistical analysis to compare threats and these variables
phylogenetic conservatism is measured by
looking to see whether evolutionary distance correlates with differences in traits
evolution is faster
outside of the tropics
evolution is slower in
small, wide-ranging & generalised groups
Niche conservatism greater in the
in the tropics
Niche conservatism is quicker in
small, wide-ranging & generalised groups
phylodiversity - prioritising
- Some areas and groups are more or less adaptable in the face of threats
- Some areas contain more unique species than others
- Phylogenies contain unequal distributions of species
- Based on phylogenetic information can prioritise
Phylogenetic diversity:
is defined as the total amount of history shared by a group of species
Phylogenetic diversity: further back they’re connected back in their phylogeny the
higher their Phylogenetic diversity
what should be an important consideration in deciding which species to conserve?
PHLOYGENY
conservation should aim to
conserve as wide a range of phylogenetic diversity as possible
what should be focussed on conserving;
- Focus away from species rich groups in which individual species are threatened
- Focus on evolutionarily distinct species
- This is because phylogenetic diversity correlates with genetic and functional diversity
speciation is high on
islands
past rates of speciation ____ to estimate
difficult
current areas with high richness known as
hotspots
hotspots;
- -These are areas of currently unusually high diversity
- Prioritising these will maximise conservation of phylogenetic diversity
- Also serve as pools of species in the future -> future speciation
