Evolution In Real Time Flashcards
What do we know about the rate of evolution?
Evolution is gradual
Proceeds by accumulation of small changes
Big jumps are unlikely
Rate of evolution varies through time
Macro is slow but micro can be fast
What is an example of rapid micro-evolution?
Moths (pollution causes darker phenotype)
Very fast response to change
Why might a species go extinct if there is competition?
Two species with very similar requirements cannot coexist
One must go extinct or evolve different requirements
Ecological process of extinction faster than evolution so this more likely
How can human impacts lead to rapid evolution?
Selective hunting
Bighorn sheep:
- Large rams are a target
- Causes reductions in animal size, horn length, and fluctuations in pop size
Cod fishing:
- Nets target larger fish
- The larger, later maturing fish are fished out before they can reproduce
How can climate change affect phenology of flowering plants?
- Won’t grow as fast or survive as well as not adapted to new conditions
- Optimal to flower earlier so as not to waste time and resources
- Produces fewer seeds or may be dead so don’t reproduce
What happened to rabbits in Australia?
European rabbits introduced in 1859
- Large capacity for reproduction
- Reached pest status
- Used biological control of myxoma virus
What was the mortality of the Australian rabbits?
1st epidemic - 99% - spread very quickly
2nd - 90% - pop recovers
3rd - 40-60% - biological control becomes ineffective
What do selection pressures of parasites select for?
Lower virulence, as this leads to more secondary cases
- Less severe symptoms but host lives longer and spreads disease
Higher exposure -> resistance
High virulence would lead to short periods of spread
Why do parasites evolve rapidly?
Large number of generations in a short time
Intense selection pressure on hosts
So rapid evolution
What is phylodynamic data?
Data taken from pathogens using modern evolutionary methods and put together with immunological data
What is the measles phylogeny vs the influenza phylogeny?
Measles - very branched with multiple different lineages
- No selection on the virus, spread randomly
Influenza - Mostly follows a singular lineage
- Reveals imprint of selection
What can phylogeny tell us?
About the evolutionary history of a group
Which lineages have gone extinct and when
Can map other data and look at phylodynamics
What causes the peaks in the measles and influenza cases?
Measles - consequence of the school calendar
Influenza - Consequence of selection, mutation and evolution
What are other applications of fast evolution?
Evolution of pesticide resistance
Cancer treatments and drug resistance
Superbugs
