Class Notes (837,696)
Canada (510,399)
Psychology (5,220)
PSYCH 1XX3 (1,109)
Joe Kim (1,028)

Psych- Evolution.pdf

7 Pages
Unlock Document

Joe Kim

Critical Period Research - Differences in brain structure were observed in rats raised in either enriched or deprived environments Implications Of Critical Periods - Likely to affect parental decisions o Can lead parents to over-stimulate their children before they are even born - Could affect decisions to adopt o Can lead people to not adopt older children - Affects public policy on child intervention Experience-expectant Brain Growth:Brain has evolved to expect a certain amount of environmental input and with this input it can develop normally. Experience-dependent Brain Growth:Brain develops according to personal experiences. Sensitive Periods - Replaced the term critical period - Brain maintains some residual capacity for change and growth in adulthood - Flexibility in the timing and type of stimulation required for normal development Evolution I Adaptation: Biological traits (characteristics) that help an individual survive and reproduce in its habitat. - Perform a specific function that makes an organism better suited to its environment - Ex. Human eyes, raccoons’ paws, bat’s echolocation systems Adaptationists - Biological adaptions include perceptual processes and behaviours - Look for relevant adaptations Higher Mental Processes - Selective attention - Memory encoding - Memory retrieval - Word recognition Evolution By Natural Selection - Natural Selection: Differential survival and reproduction of organisms as a result of heritable differences between them. o Discovered by Charles Darwin and Alfred Wallace - [1] Individual Differences - Within any population there’s variation among individuals for any given characteristic - [2] Differential Reproduction - Caused by differences affecting individual’s chance of survival and reproduction - Some individuals will have offspring than others - [3] Heritability - Heritable traits are passed to offspring - Offspring of successful reproducers will resemble their parents Selective Transmission - From above: [1] + [2] + [3] Î Î Selective Transmission - Ex. A school of red and blue fish - [1] Red fish are red, blue fish are blue - [2] Blue fish camouflage in the ocean and are less visible to predators - Red fish are more visible to predators and get eaten more often - On average, blue fish survive and reproduce better than red fish - [3] Blue fish produces blue-coloured offspring - Over many generations, there’ll be selective transmission of heritable parental traits and the population will be mostly blue - The specific traits that are best adapted for survival/reproduction are going to be reproduced at higher rates Stabilization Selection - Selection against any sort of departure from the species-typical adaptive design - However, sometimes significant environmental change causes selection to favour traits that aren’t typical - Ex. Darwin’s finches - Finches normally eat small seeds - Drought Æ Food became scarce Æ Small seeds quickly eaten Æ Large, tough seeds remained - Birds with large beaks continued to survive - Birds with small beaks died from starvation - 1976 – 1978: Average beak depth increased from 9.4mm – 10.2mm - Beak size is inheritable Æ Offspring inherited large beaks Survival Of The Fittest - Fitness refers to reproductive success (in evolutionary biology) - Natural selection favours those who are best at producing offspring - Darwinian Fitness: Average reproductive success of a genotype relative to alternative genotypes. - Fitness is used to describe how good a particular genotype is at leaving copies of its genes in the next generation relative to other genotypes - Evolution:Changes in allele frequencies over time. Sexual Selection:The component of natural selection that acts on traits that influences an organism’s ability to obtain a mate. - [1] Being chosen by the opposite sex - Ex. Peacock’s tail (a sexually selected trait; only in males) - Trait: Display feature - Effect on survival: Negative - Effect on fitness: Positive - Selective Force: Female choice - Useless with respect to physical survival o Energetically expensive to produce o Increases risk of dying (conspicuous to predators and heavy to carry) - Useful with respect to mating o Tail is attractive to females - [2] Defeating same-sex rivals in mating competition - Ex. Elk’s antlers (a sexually selected trait; only in males) - Trait: Weapon - Effect on survival: Negative - Effect on fitness: Positive - Selective Force: Success incombat - Useless with respect to physical survival o Decreases speed and stamina, thus vulnerable to predators o More likely to get stuck indeep snow - Useful with respect to mating o Used in combat with other elks when competing for mate - In general, if anatomical trait differs between sexes Æ hints a sexually selected trait Mechanisms Of Evolution - Natural Selection - Mutation - Genetic Drift - Sexual Selection - Migration (Genetic Flow) Species-Typical Behaviour - Behaviours are evolved, species specific adaptations - Includes topography (physical form), habitat preference, and group size - Behaviour genetics experiments can be performed to test if behavi
More Less

Related notes for PSYCH 1XX3

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.