Topic 7: Evolution and You: Global Change Flashcards
When faced with change, as species can (3 things)
Show phenotypic plasticity - change their phenotype to one that better deals with the selection pressure
Evolve or adapt
Go extinct
Phenotypic plasticity
Some organisms can alter their phenotype and express different traits (or behaviors) depending on the environmental conditions
This does not require genetic change
But if there is a genetic bias for phenotypic plasticity, we might see the evolution of plasticity
Temperature and climate effects on breeding
Animals have evolved to use cues like daylight and temp to choose when to breed
They want to maximize the number of offspring and minimize costs (like finding food)
Timing breeding is a challenge
Picked the window when there would usually be the most food to support them
Shaped by natural selection and so hard to build flexibility into this system
Trade offs for breeding
Early is good if it means you can have more kids but bad if a cold snap kills them all
How well different breeding phenotypes do depends on
How stable and predictable an environment is
How quickly individuals can recover from a failed breeding attempt
Trophic mismatch
Timing of migration and breeding need to coordinate with food timing
Changed in this food timing will influence the populations that depend on it
If they cannot adapt, they die
Speciation due to climate change
Blackcaps
Usually got to Spain for winter
Now some go to the UK cos its warm enough for them now
They do assertive mating and UK migrants mate with uk migrants and Spanish with Spanish
Over time This could lead to gene change and speciation
Habitat fragmentation
If a creature has a wide habitat it does not mean it can access all of it. Not all will be suitable (particular niches etc) and there may be farms or roads or cities occupying part of it.
This can lead to islands or fragments of habitat not connected to each other
Food pyramid
Lots of producers at the base support a smaller number of consumers etc etc up to apex predator
primary producers
secondary, tertiary and quaternary consumers (apex predator)
Trophic cascades
Jaguars eat herbivores which eat plants.
So plants increase.
Habitat disruption: noise
Humans are noisy
Noise pollution affects birds in noisy environments
Can be thought of as
phenotypic plasticity
social evolution as birds learn songs from other birds
genetic evolution
Lombard effect
Humans raise their loudness and pitch when ambient noise increases. So do birds.
Male birds must sing to attract a mate. But must now sing higher and louder. But doing so may alter other aspects of their song.
