Life Science 15: midterm (UCLA)

What is scientific thinking used for?

to create a better understanding of the world. there are 5 steps

How does scientific thinking work?

1. making observations

2. formulate a hypothesis

3. making a prediction

4. conduct an experiment

5. conclusion

example of scientific thinking....

I have observed that when people take steroids they become bigger. therefore I would apply all five steps to this hypothesis to receive an outcome.

How does a hypothesis differ from a theory?

A hypothesis is a provisional or working explanation, assumed true only to guide experimentation or for the sake of argument. A prediction is an assumption made from anecdotal observations.

what does it mean to control an experiment?

a group of subjects who are treated identically to an exprimental group with one exception. EX: one group recieves steriods while the other group does not. We are controlling how much they eat,sleep, and train to identify the specific different outcome of the people taking steroids and not.

Pseudoscience

set of claims that seems scientific but isn't EX: Autism and Vaccine correlation

compare and contrast pseudoscience to superstitions and anecdotal science

EX: pushing an elevator button to make the elevator come faster. Or the rats pushing the lever with delayed time creating a "superstition" to be preformed in order to retrieve the treat.

more and more observations that support a hypothesis to be true, does this make it true?

no, because scientist can only become more and more confident within a "theory" or "hypothesis." these

What is evolution?

change in allele frequencies in a population over time

When can evolution occur?

evolution can occur when there is 4 different ways

1. Mutation

2. Migration/ genetic flow

3.Genetic Drift

4. Natural Selection

Mutation

a drift aleration of DNA/ ones alleles is changed to another. This is essential to the population. EX: radiation can change allele/DNA

What is natural selection?

1. Variability of trait

2. heritable

3. differential reproductive success

gentic drift

Random change in allele frequencies

migration or gene flow

the movement of some individuals of a species from one population to another

Ideas and observations that influenced Darwin?

During his research he was told that all species are the same and extinction doesn't exist. on his travels around the word for came across two species that looked very similar, yet were not the same. (Finch). these species were on two different places and he realized that "evolution" had occured

1. mutation

2. genetic drift

3. Migration/ gene flow

4. Natural Selection

why does artificial selection always work?

This theory always works becasue it creates a population that has some change. within this natural selection occurs therefore it makes this theory successful.

how is genetic drift related to Mendel's 1st law?

they are connect becasue genetic drift is a random change in allele frequency and mendels law is mandated from the segregation of gametes in a maternal and paternal figure. therefore both of these activities happen randomly.

who is Mendel? what was his first law?

His first law was segregation, making genetic drift relatable because over time a population is able to change due to the change is allele frequency. when natural selection occurs this creates the ability to inherit different alleles creating a small genetic drift to the offspring from the paternal and maternal figures.

What is sexual selection?

Natural selection and differential reproductive success.

why does sexual selection lead to trade offs?

for example, peacocks have a large feathered tail which increases the reproductive success "fitness" due to the female being more attracted to the biggest feathered tail, however, it decreases the survival. (frigiet bird- big red chest)(deer - big antlers)

what are norm of reactions? How does the slope describe relationship to environment?

the set of all phenotype expression that are possible for the given genotype if raised under all possible different environment.

Phenotype

An organism's physical appearance, or visible traits.

Genotype

genetic makeup of an organism

use an example to explain what evolutionary miss match is?

what the environment changes too fast or an individual is taken out of adapted area. EX: humans --- food. in the hunter gather word food was extermely scares and now in todays society was have grocery stores and there is much more food therefore humans are constantly over eating because we are still biological program to believe we will run out of food. this is an outcome of the environment changing too fast and evolution hasnt gotten the chance to catch up.

dominant allele

An allele whose trait always shows up in the organism when the allele is present.

Ressesive

Gene that will only appear if no dominant gene is present.

why do offspring look like parents? but not exactly the same?

offspring generally resemble the parents however they don't look exactly the same becasue they only inherit one copy of gametes from each parent. therefore only 50% of the DNA is passed down which doesn't allow the offspring to look identical to the parents.

how is mendel's law of segregation relevant to gamtete produce

this is becasue all of the gamete are diplod meaning that there is only 1 gamete from maternal and paternal figure which will produce 2 gamete in the offspring

how does mendel's study of peas help us with everything else?

the pea plants are able to stay in one place at a time creating a very easy system to test the organisms. these organisms also stay diplod through while the gametes are hapliod

how do you predict offspring genotypes of sex-linked traits?

all sex-linked traits will always be held within the sex chromosome which is also known as the x chromosome. EX: colorblindness is carried on the X chromosome. females are carriers and males are more likely to have colorblindness due to only having one x chromosome.

the human genome

46 chromosomes and 23 pairs

how does sex determination for different species varies?

EX: Humans have differences in the chromosomes. XX for the females and XY for the males. a species that differs from humans are birds. in birds the female is responsible for the sex determination as the female hold XZ and the male hold XX. same with bees,ants,wasps,turtles.

does having a particular genotype ensure that you'll have a specific phenotype?

No, becasue this would mean that the norm of reactions distribution is flat.

using blood types, explain how multiple alleles in population work?

1. AB*O=A

2.A*O= B

3.A*AB=AB

4.O*O=O

What does Hamilton's Rule help us understand?

Hamiltons rule: B times r > C

Helps us understand why an individual would appear to act altruistically - when benefit to the relative times their relatedness is greater than personal cost

Helps predict when we will see kindness

evidence that supports Hamilton's rule

genetics prdiction. EX: giving a kidney to someone one really needs it. we are more likely to only do this for someone that is our kin.

how to calculate coefficient of relatedness

offspring = .5 half siblings =.25 cousins =.125 grand child =.25 shared alleles

unexpected coorperation and conflicts, when and why do we see them?

EX: mole rats. we see this becasue there is so much inbreeding that there is a high level of relatedness between the individuals. we see some mole rats give up there own reproductive success to help another or the queen have reproductive success.

rules of thumb

doing what is best to increase your own fitness.

describe three strategics for for increasing between unrelated individuals

detect cheaters and punish them. be kind to those that can help you in the long run.

what is the determination game and how does it realate to reciprical alturism

the game that gives you two ultimatums. $40 dollars divided to 35-5 or 15-25.

We would typically reject the $5 to punish the other player for the stingy play. the reputation of the player also matters. if the game was to be played in front of a crowd you want to be viewed as more generous.

EX: if humans were to play the game with a computer we are more willing to take both offers becasue we no longer feel the need to punish the other player.

direct fitness

derived from an individual's own offspring

inclusive fitness

direct fitness + indirect fitness

indirect fitness

the fitness that an individual gains by helping relatives pass on copies of their genes

what is STR locis and how do they differ?

How does DNA fingerprinting work?

Each person (apart from

identical twins) has unique

DNA. This means that they

can be identified using "DNA

fingerprinting"

although science has DNA fingerprinting is universally excepted, why does it have some criticisms?

within criminal court cases there are so many possibility and chains of evidence. does the jury fully understand whats happening? EX: (class) we spoke about how there are very similar fingerprint and there could be very similar around the world. there is not diffident answer.