Animal Behavior Exam 1

evolution

a change in gene frequency over time

• can occur without natural selection

• population composition changes from one generation to the next

3 necessary components of evolution by natural selection

variation, inheritance, differential reproductive success

variation

individuals differ from one another in a population

inheritance

differences are passed from parent to offspring

differential reproductive succes

some individuals are more successful at survival or reproduction than others because of their traits

fitness

an individual’s ability to survive and reproduce

adaptation

a trait that increases an organism’s fitness relative to the individuals lacking it

proximate cause

the mechanistic underpinnings of a behavior

ultimate cause

the evolutionary reasons of a behavior

fitness cost

the reduction in the number of surviving offspring produced because of a certain behavior

fitness benefit

the increase in the number of surviving offspring produced because of a certain behavior

energetic cost

energy the animal expends performing the behavior

opportunity cost

benefit the animal forgoes by not performing other behaviors during the same time

risk cost

increased chance of being injured or killed

observational approach

watching what an animal does and correlate this with elements of the social or ecological environment (takes advantage of natural variations)

experimental approach

mainpulate features of the animal or environment and observe the behavior and how it changes with manipulation

comparative approach

look across species on the phylogeny to find the patterns of behavioral evolution

phenotype

manifestation of traits on the individual (physical)

genotype

genetic component of the individual

environment

non-genetic influence, can be ecological or social

individual level

development of the phenotype requires both genes and environmental input

population level

variation of phenotypes can be determined mostly by genetics, environment, or by interaction of both

gene expression

influenced by a variety of internal and external cues (age, cell, social and ecological environment)

epigenetics

chemical modifications on the DNA or histones can influence transcription level without changing the DNA sequence itself

miRNA

a small, non-coding RNA molecule that regulates gene expression in cells

forward genetics (observational)

identify genes that are associated with a given phenotype

reverse genetics (experimental)

identify what phenotype arise as a consequence of an allele/certain allelic combination

behavioral development

is caused by changes in gene expression

genetic variation

base skin color determined by genes from parents (heritable)

environmental variation

skin gets tanner as exposure to sun increases (not heritable)

genotype by environment and interaction

light skin burns more readily in the sun whereas dark skin tans more readily in the same amount of sun

common garden

both genotypes are placed in the same environment

• if partly genetic, there will be differences in phenotype

• if entirely environmental, there won’t be any differences

reciprocal transplant

placing each of the genotypes in 2 different environments

• if based on genetics, will fully depend on the genotype of the tree

• if based on environment, both will have the same type of variation

phenotypic plasticity

the ability for the same genotype to develop different phenotypes in response to different environments

behavioral polyphenism

a type of phenotypic plasticity in which discrete phenotypes arise from a single genotype (environmental)

behavioral polymorphism

discrete behavioral phenotype due to genetic differences (genetic)

innate behavior

genetically hardwired or stereotypical and can perform without prior learning, resistant to environmental variation

learned behavior

influenced by the environment; required learning from prior experiences in interacting with the environment

sign stimulus (releaser)

the cue required for innate behavior

fixed action pattern (FAP)

the stereotypical behavioral response

innate releasing mechanism

the neural network responsible for the activation of the instinct

ethology

the study of animal behavior

neuroethology

the study of the neural basis of natural behavior in animals

sensory systems

captured environmental stimuli

central nervous system/neural network

filter and process information

action potential

the all or nothing change in membrane electrical charge

• always fire at the same amplitude but the strength of a signal is determined by the frequency of the firing

sensory modality

the different “channels” through which animals percieve information

• visual, acoustic, tactile, chemical

stimulus filtering

the ability for neurons and neural circuits to ignore irrelevant stimuli and focus on the relevant stimuli

sensory peripheral level

changes in sensory organ morphology, number of sensory cells, sensitivity of the sensory neuron

central nervous system level

differences in the sensory cortex that is dedicated to processing the information

humans

have 3 types of cones

• each are most sensitive to long, median, and short wavelengths

• CNS interprets the information based on the relative signal strength from the three types of cones

• animals differ in not only whether they can sense a certain wavelength, but also the degree to which they can tell 2 colors apart

private channel

• conspicuous sexual ornaments such as color can attract mates, but attract predators

• animals can take advantage of the differences in sensory system to communicate within a private channel that other species can’t detect

• ex. damselfish

swordtail

use UV as a private channel to attract mates, without becoming more conspicuous to their predators