Evolution and Behavior Flashcards
Why are we smarter than other vertebrates with larger brains than us?
our body mass to brain mass ratio is much higher than other animals. we also have more neural folding and a larger neuronal density compared to other animals.
T/F: our brainstem and midbrain has been conserved through a variety of species
true. Our cortexes differ in size but they are structurally similar to other vertebrates, and our brain stem adn midbrains has been conserved.
why do land dwellers typically have larger brains than water animals? what is an exception to this?
in order to survive on land, a larger brain was needed to have more refined survival processes. Brain structures relating to skills needed for terrestrial survival began to evolve.
ex/ structures in thalamus and brainstem needed to alter in order to coordinate how to brreathe without water
exception: whales have large brains but live in the ocean.
- they evolved into land animals ( got larger brains) and then evolved back into water dwellers
- vestigial proof of theory
encephalization quotient
comparison between brain size to body mass. Humans have the largest encephalization quotient: we have the largest brain compared to body mass
Innate vs learned behavior
innate behavior: behavior that comes naturally due to an inherent physical trait that allows them to express the action (ex/ a sharp beak allows certain birds to ear pinecones)
learned behavior: a behavior that is taught to an animal through experience or from their parents, usually there is no physical mechanism that allows for a learned behavior
ex/ a baby rat must learn how to crack open a pinecone from its mom, it does not have a sharp beak trait to do it naturally.
how do conditions favor innate vs learned behavior?
learned behavior facilitates innovation and can occur in a more social condition. Larger brains also facilitate learned behavior over innate behavior.
having a larger brain makes you capable of EXPERIENTIAL LEARNING and MIRROR LEARNING.
larger brains= increase plasticity and behavioral flexibility and trial and error learning.
Charles Darwin proposed evolution through ___ ___
natural selection.
Charles Lyell published a paper called ____ which suggested that:
published principles of geology: suggested that features of the earth are PLASTIC and every changing. Also noted that fossils of older layers of earth are structurally different than newer fossils, suggesting that species may change over time.
layers of rock and fossils can show a timeline; the earth may be older than what the church says it is.
___ ___ introduced competition theories, whihch states that all organisms are able to over-produce, which leads to competition and a population decrease because the earth and its resources can only sustain a fixed number of organisms.
Thomas Malthus –>”Our environment has a fixed capacity for the number of organisms that it can sustain”
success
term given to an animal that lived long enough to reproduce in a competitive environment.
3 Main evolutionary principles
1) competition
2) variation: sexual reproduction and mutation ensure offspring are non-identical, which causes differential success for each individuals and shifts genotypes/phenotypes towards favored traits.
3) adaptation: individuals whose characteristics are best fitted to the environment will survive to produce more offspring.
Behavioral Functionalism
the idea that behavior is subject to evolutionary pressure and that every behavior of an animal must serve a purpose to enable an aspect of survival or reproductive success.
if the behavior served no purpose, the trait would’ve been lost.
there is a reciprocity between brain mechanism and behavior
Describe to reciprocity between brain mechanism and behavior.
each species has a unique and functional behavioral repetoire which is intertwined with physical characteristics. A brain mechanism allows for a certain behavior, and certain behaviors allow for trait propagation. If you do not exhibit a certain behavior, it is likely because there is no mechanism in place for that behavior, but at the same time, if you have a physical characteristic that is not utilized (behaviorally), the physical characteristic will also decline in the population.
what is “potential” in terms of functionalism
sometimes the lack of physical attributes characterize a change in BRAINcapacity and behavior to allow the organism to survive without the physical characteristic.
so being physically weak = mentally stronger
ex/ Birds are dumb because they can fly
describe a scenario in which selection plays a role in cognitive abilities
ex/ using articificial selection: “dumb” rats who made lots of mistakes trying to get out of a maze were bred together, and “smart” rates who got out of the maze were bred together. Over a few generations, the “dumb” rat lineage made even more errors than their parents, and “smart” rat pups got out of the maze faster than their parents. There was a compopunding of cognitive abiliteies.
convergent evolution
process by which genetically non-identical species (unrelated species) independently evolve similar traits as a result of having to adapt to similar environments
divergent evolution
accumulation of differences between groups which can lead to speciation, or genetic distinction. Groups are no longer closely related.
causes of speciation and divergent evolution
reproductive isolation or geographic isolation
sexual selection
preference for certain traits within the opposte sex of the same species; causes propagation of the desired trait.
describe how sexual and natural selection may work against each other
sexual selection may impede other adaptations and get in the way of survival, but it facilitates reproduction
ex/ a peacocks plume attracts predators (decreased survival) but it also attracts females
which sex drives sexual selection
females drive sexual selection and drive the formation of ENHANCED secondary sexual characteristics by choosing males with desired traits.
Intersexual competition
organisms of one trait choose characteristics of the opposite sex
intrasexual selection
animals compete with members of the same sex for access to members of the opposite sex (ex/ male deer fighting)
mimicry as an adaptation
appearing as a predator or appearing as a different species in order to avoid predation. Selection for specific traits to prevent predation; adoption of features that resemble an organisms predator
How does mimicry come to be?
PREDATORS drive mimicry adaptions as their prey evolve to adopt specific patterns.
Warning colors as an adaptation
prevents predation by signalling toxicity; warning colors can also be mimicked by animals that are not inherently toxic (ex/ viceroy moth mimicking the colors of a toxic monarch butterfly.
Maladaptive traits
mutations that reduce the fitness of an animal. ex/ albinism
homological structures
structures within RELATED species that RESEMBLE one another but are functionally different (ex/ human forearm bones and bat wing bones)
Analogical strucutres
structures that serve the same function, but do not arise from evolutionarily related structures Ex/ wings on bats and wings on insects)
natural selection operates at the ____ level, and the ____ is passed onto the next generation
natural selection operates at the PHENOTYPIC level (selection for physical or behavioral characteristics), and the GENOTYPE is passed onto the next generation.
genotypic frequencies change over generations as a function of reproductive success of a phenotype
desribe how genes, the brain, and the environment all tie together to facilitate evolution
1) evolution influences the genes that are available to members
2) genes code for neural structures
3) the nervous system is physically created by genes, but its development and cultivation depends on the environmental pressures.
4) the cultivated nervous system and environment create the current individual, and their thoughts and feelings.
5) the state of the current individual as well as the current situation plays a role in how they behave
6) current behavior as a result of the current organism ini the current environment influences the likelihood that the behavioral genes (aka the genes that coded for the particular mechanisms that allowed the overt behavior to happen) will be passed onto the next generation.
- therefore, the overt behavior determines survival and reproduction and thus drives evolution by the propagation of the genes and mechanisms that allowed for that behavior.
Human evolution address
Domain: Eukarya Kingdom: animalia Phylum: chordates Class: mammals Order: Primates Family: hominidae Genus: Human Species: Modern Human (sapiens)
Which one of charles’ darwins work was the most controversial?
the descent of man; contended on man evolution.
two theories about human migration
Out of Africa: theory that modern humans evolved in the rift valley of africa, and then later migrated to Europe and east Asia before moving to North America
Multiregional Migration: ancient humans evolved in out of africa, migrated to all parts of the world, and then evolved into modern humans.
most results point to the out of africa theory of migration.
How did diet play a role in human evolution?
studies show that primates wiht larger brains eat more fruit. larger brains needed to scout out ripe fruit? or eating fruit rather than bark provided essential nurients for brain development and metabolism maintenance?
Forces of evolution
1) mutation
2) gene flow (migration)
3) genetic drift (bottle neck or founder effects)
4) natural selections
selective advantage
characteristic of an organism that permits it to produce more than the average number of offspring
evolution
gradual change in the structure and physiology of plant and animal species, generally producing more complex organisms as a result of natural selection.
5 notable factors in human evolution
1) climate change; adaptation to climate/ ex/ in hotter regions, people are more tall and slender for heat dissapation, in colder regions, people are more short and robust for heat conservation.
climate change also may have resulted in diet change and humans evolved to have a more diverse diet than their related species.
2) bipedalism
3) grasping hands: oppositional thumb increases manual dexterity
4) langauge: theory of mind, social skills, learning and teaching.
5) neoteny
How has bipedalism facilitated human evolution?
bipedalism allowed for further migration because it was energetically efficient rather than crawling, allowed humans to cover larger distances and occupy larger land masses.
bipedalism could have also led to increased brain size by freeing up forelimbs and leading to the expansion and reorganization of the sensory and motor brain areas the process sensation and control movement. Bipedalism may also have pushed towards a reorganization of the prefrontal cortex and expansion of the visual cortex now that a person’s visual field grew larger due to standing on hind legs.
bipedalism also posed an obstetric dilemma; the switch to walking on two limbs reconfigured the birth canal and narrowed the pelvis of humans; as bipedalism was happening, brain expansion also was happening, and it was disadvantageous to have a smaller pelvis. (but a skull formation adaptation dealt with that)
How did humans evolve to overcome the dilemma of having a narrower pelvis but larger head?
babies are born with FONTANELLES that enable the head to compress during birth in order to pass through the birth canals. these fontanelles remain open for the first couple years of life allowing for a MASSIVE INCREASE IN BRAIN SIZE. these adaptation was also seen in previous species before humans, such as from Australopithecines, who also followed a similar pattern to the anatomical growth of humans.
This is partially known as neoteny: and evolutionary factor that helped with human progression which encompasses sustained brain growth due to slow maturation.
How has neoteny helped with human evolution?
neoteny: a slowing of the maturation process, allowing for more time for growth, including brain growth. Althouh human babies are born essentially helpless because they are born early, neoteny is a better trade off because they develop larger brains in the long run.
Slow maturation allows for the retaination of brain plasticity and juvenile characteristics, allowing for the more learning and experience to take place.
- increases the amount of creativity and innovation.
- prey species do not exhibit neoteny because it is TOO EVOLUTIONARILY DISADVANTAGEOUS to have slow-developing young. They must be able to develop fast to prevent being killed before they can reproduce. they are precocial species.
Precocial species
species that are born essentially fully developed and mobile at birth. They are often prey species that need to be able to keep up with the herd hours after being born.
humans are ____ species where as deer and prey animals are ____ species.
humans are altricial species where as deer and prey animals are PRECOCIAL species.
what do social biologists do?
they study the social behavior in non humans animals and make comparisons across species aka edward o wilson.
Heuristic Approach to a study
a working model of a study
in the “expression of the emotions in man and animals” by Darwin, he suggested that:
we can automatically process other peoples emotions. It is evolutionarily advantageous to process others emotions because EMOTIONALITY CONVEYS INTENTION (conveys danger)
Principle of Antithesis:
opposite of emotions generate opposite behaviors: ex/ tail up= happy but tail down= sad
do humans follow the principle of antithesis?
no. animals convey emotions directly into associated behaviors, but humans can act differently than their emotions.
How does our role in society affect or behaviors? (compare to emotional effects on behavior)
humans are not always emotional. We pursue goal directed behavior rather than emotional behavior. Our ROLE in society elicits a given behavior regardless of our emotional state (to an extent).
ex/ 2 people could have the same role as a student, and thus they both go to class (behave the same due to the same role), but they may have different emotions at a given time.
rules may be unsaid or _____
scripted
what is a scripted rule? What must humans have in order to follow a scripted rule?
set of prescribed behaviors on how to react and behave in certain situations.
requires ability to read people and to have relative memory; we need a THEORY OF MIND in order to account for other people’s situation: rules on how to talk to individuals depending on scenario.
most mirror neurons are located in the _______ and the _____
located in the VENTRAL PREMOTOR CORTEX and INFERIOR PARIETAL LOBE that responds when an individual watches someone else perform a movement.
mirror neurons allow for 3 main things:
1) imitation
2) empathy
3) theory of mind
how does a mirror neuron allow for empathy? How does our brain prevent mirror neurons from getting out of control?
mirror neurons fire when we watch someone else experience something or perform a certain action. It alerts us that we ourselves are being touched when in fact someone else is being touched.
Our SENSORY neurons repress MOTOR neurons and prevents us from actually sensing someone else being touched, or else that would be super overwhelming. Without our motor neurons being repressed by our sensory neurons, we would feel touch when someone else is touched due to our mirror neurons.
How do mirror neurons give us a heightened theory of mind?
mirror neurons provide a basis for a heightened theory of mind because it allows for the VICARIOUS EXPERIENCE of other people’s experiences. Theory of mind is a STEP HIGHER THAN MERE IMITATION, and it is a prerequisite for communication.
what happens to the mirror neurons of EMTs and individuals who deal with trauma regularly?
repeated trauma= less mirror neuron response to certain situations, allowing EMTS to remain a bit more detached in an emergency situation.
