New Caledonian crows have the capacity for
abstract thought (use one tool to access anohter tool that will help them reach food)
behavior (evolves)
internally generated response to external stimuli
- can evolve via natural selection due to effect on fitness
- vary from individual to individual
- variation at least partly genetic
Fox experiment
docility in foxes can be a learned behavior through specific breeding [genes influence behavio]
- Response to artificial selection extremely rapid
- QTL analysis shows heritable behavior with fox pop. (aggressive behavior correlated with neural crest cells)
Genetic influence on behavior
- Moment-to-moment
- Development
- Selection
Basically, behavior can be artificially selected for in animals
Tinbergen
laid foundation for study of behavior from evolutionary perspective, four questions:
- How does it work?
- How does it develop?
- What is its adaptive value?
- How did it evolve?
juvenile stickleback sfrom freshwater lakes were
less social, more aggressive towards conspecifics, and less likely to school
under gentic ontrol, oldfield mice produce
distinctive burrow
Behavioral ecology
science that explores the relationship between behavior, ecology, and evolution -> highlights significance of animal actions
Proximate Causations
explains biological functions via immediate physiological/environmental factors (how behavior is elicited)
Ultimate Causations
explains traits via evolutionary forces acting on them
Identify behavior in organisms without brains (why particular behaviors evolved)
Cellular slime mold (Dictyostelium discoides)
organism without brains can behave in complex ways
Cope with starvation -> cells join to form a “slug” -> produce spores, but die in formation process
Plants (brainless organism)
- Venus fly traps: leaves shut to capture insects
- Australian sundews: catapult mechanism to trap insects on sticky “tentacles”
With Brains
use neurons to control behavior
Voltage spikes travel down neuron, triggers release of neurotransmitters at synapse -> triggers activity in neighboring neurons
Early nervous system
Alalcomenaeus (520 mya, very similar nervous system to modern relative)
Nervous system evolved via gene co-option
Agreement
genes for cell-to-cell communication co-opted
Uncertain
if earliest multicell animals had nervous system or if it can from more derived animals
Sponges lack nervous systems, however
make homologs of proteins found in neurons
Two hypotheses via origins of nervous system
ctenophores w/ pivotal role
- Nervous system evolved in common ancestor, but lost in sponges
- Nervous system evolved in ctenophores (sponge ancestor?) independently (more evidence supports this one)
Innate behavior
behavior that is genetically hardwired in organism, can be performed in response to cue without prior experience
Synaptic plasticity
ability to strengthen and weaken over time via increase/decrease in activity
[ex. Dendritic spins grow from learning behaviors]
Benefits of living in a group
- Increased vigilance
- Dilution effect (safety in numbers)
- Enhanced defense capability
- Cooperative foraging/hunting
- Improved defense of critical resources
Costs of living in a group
- Increased visibility to predators
- Increased competition for food
- Increased competition for mates
- Decreased certainty of paternity/maternity (polygamy/cheating more often)
- Increased transmission of disease/parasites
Tidbit
wild dogs, unlike orcas, do NOT have group size limit, success usually stays the same/increases as group size increases
Inclusive fitness
direct fitness + indirect fitness (WILL BE FINAL QUESTION RELATED TO THIS)
Direct fitness
organism’s own success in transferring alleles to future generations
Indirect fitness
reproductive success of other individuals carrying same allele
also explains altruism via potential to pass on same alleles to offspring
dilution effect
safety innumbers that arises through swamping the foraging capacity of local predators
Kin selection
selection from indirect benefits of helping relatives
Inclusive selection leads to kin selection via accounting for both your own fitness and the fitness of those related to you, coefficient of relatedness w/ greater chance of success of carrying down similar alleles
HAMILTON’S RULE
describes when altruism is favored
rB>C
Female ground squirrels (kin selection)
do not venture far from birthplace (unlike males), more likely to give warning calls
If hawk seen, net benefit of alarm (warns relatives), but danger to squirrel who made call
White-fronted bee-eaters
during drought, offspring stay with parents and help raise siblings
Giant water bugs
males keep eggs on back, aerate via coming to water surface (very risky)
Certainty of paternity via only accepting eggs after mating with same female several times
Male side-blotched lizards
3 different behaviors, varying frequency from year to year based on mating success (types oscillate in frequency over time) ornage, blue, yellow
Bred flies
quickly learned to identify quinine laced bread -> fast-learning flies produced fast-learning offspring -> cost: fast-learning flies died sooner than normal flies
capacity to learn can evolve, but may come at a cost
earliest fossil evidence of brain
vertebrate development was the evolution of the brain, 530 bya Haikouichthys
vertebrate organization is
relatively conserved
Bilaterian (organisms with right and left sides) development
trend towards cephalization (concentrating scent organs into “head”)
Somatosensory cortex
senses, if function occurring inside and outside (pictures shows enlarged areas where somatosensory cortex effect is strongest) -> disgusting
Cerebellum
maintaining balance
Broca’s area
speech
Prefrontal cortex/neocortex
attention, thought, perception and episodic memory
Hypothalamus
homeostasis
Amygdala
emotional responses
As you get older your amygdala degrades, meaning that you have a less of a social filter
parts of brain vary in size depending
on vertebrate species
Complex (sometimes not understandable) animal behaviors
- Octopus “randomly” hits passing fish, no reason found, did it have a bad day?
- Chimps communicate via gestures, can identify group based on these gestures
- Dolphins wear sponges to protect rostrum (nose) during feeding