Adaptation

Proximate

questions that address the immediate

ultimate

questions that demand deeper, historical interpretations

Adaptations

traits that evolved to improve rates of survival and reproduction

Adapt

to adapt is to evolve adaptive traits

Natural Selection

1. there is variation in the trait

2. the trait is heritable through the transmission of genes

3. the trait enhances reproductive success and rates of survival

maladaptive

things that reduce fitness

Stephen Jay Gould

wrote The Panda’s Thumb (1980) and introduced the term exaptation

exaptation

the process where a trait, feature, or tool originally evolved or designed for one purpose is repurposed to serve a completely new function. proposed to replace pre-adaptation

pre-adaptation

describes a trait that happens to be adapted for a new environment that it was not originally evolved for

Adaptationist Programme

using the observation, experimental, and comparative methods to study evolution by natural selection

observation method

study the trait in nature and by comparing naturally present variants

experimental method

hypothesis → prediction → experiment

aposematic coloration

bright color warns away potential predators

cryptic coloration

on natural background, the pattern is hard for predators to see

Batesian mimicry

a survival strategy where a harmless, edible organism evolves to look like a dangerous, toxic, or stinging species to trick predators

Müllerian co-mimicry

an evolutionary phenomenon where two or more unpalatable, toxic, or dangerous species evolve to share similar warning signals

Krogh’s Principle

“for many problems there is an animal on which (a physiological problem) can be most conveniently studied”

Selection experiments

comparison of selected with control populations can elucidate phenotypic, genetic, and epigenetic mechanisms

Comparative method

compare the population with the trait to other populations

• do not do a 2-species comparison! Only 3+ species!

Independent contrasts

a technique to take relatedness into account during analysis. reduces the data into independent evolutionary events, making the comparison a fair one

phylogenetic pseudo-replication

occurs when a statistical analysis treats different species as independent data points, ignoring the fact that they share an evolutionary history