acclimation and adaptations
c. evolution example
cactus vs. euphorb. not same ancestors. both developed adaptations to living in desert ENVR such as waxy cuticle, chlorophyll in stem.
Whether or not trait is adaptive..
depends on the environment the organism finds himself at.
c. evolution example 2
Platypus: electro-receptors on bill to detect prey, paddle shapes snout. Both are phlogenetically distant
Example of acclimation
arctic fox. Thick fur, lives in arctic, responds to seasonal transition in drastic ways. Accumulates fat which helps with energy and provides insulation. Fur changes color (white coat), cache (hides) food. Curls up into tight ball when sleeping (conserves heat).
Trade offs
gave a good trait but reduced in other trait. i.e. giraffes have to drink...so they spread their legs which makes them vulnerable to predation and they can slip and break legs.
two themes for class
limited resources and trade-offs
adaptation (trait under selection can be)
morphological, physiological, behavioral. All connected. Once you have one, the doors open for enhancement (i.e. morphological leads to mutations which lead to physiological and behavioral changes. SHAPED BY NATURAL SELECTION
boundary layer
traps air close to organism that minimizes wind effects. or a region of unstirred air or water that surrounds the surface of an object.
so why...giraffes
Male giraffes fight for dominance via dominance. Mal that wins gets access to females. Males with longest neck wins and have more offpsring and that trait (long neck) is expressed. Genetic corollary so females have long nexks too. Still adaptation.
wooly lousewort
Thick layer of hair which produces boundary layer and keeps the plant 34oF warmer so that it can carry out cell division etc. when it's cold. (earlier than other plants-competitive advantage)
GIraffe
Why long necks? to reach top of trees of course. However observed: during dry season they instead of eating tall trees eat small bushes. Wet season when there is less competition for food, they actually eat tall branches. Also both sexes feed faster and most often with bent neck
evolutionary ladaptation
Will survive and reproduce. Environment drives selection (IMPORTANT). Results from natural selection. must be heritable or else they wouldn't be able to evolve. Increase fitness
Fox
acclimation because over lifetime it changes its phenotype in response to environment. THIS ABILITY IS AN ADAPTATION.
acclimation
an environmentall induced change to an organism's physiology. Also known as phenotypic plasticity.
common garden experiment
see if its acclimation or adaptation. use clones so little genetic variation. keep everything the same except vary temperature.
convergent ecolution
similar environments often select for similar traits. organisms converge on traits due to similar environmental pressures
are all traits adaptations
some say yes! Some generate hypothesis: does this trait contribute to survival/reproduction. So we don't really know unless we test them