BIO 2500 Exam 1: evolution, speciation, cladistics & phylogenetics, taxonomy

define theory

broad overarching theme or concept that can be used to test infite/specific hypotheses underneath it. supported by a large body if evidence. broad theme that is testable.

example of biological theory: germ theory 1860s

Pasteur. microorganisms in the body cause disease.

example of biological theory: gene theory 1860s

Mendel. The idea that traits are passed through genetic material later discovered as DNA and genes.

theory of evolution

all living things which exist today (and many more that are now extinct) are:

1) descended from a common ancestor, and

2) adapt to their environments over time though

the process of natural selection

who proposed the theory of evolution

darwin and wallace. darwin came up with the idea and was afraid to publish it, wallace sent a letter to darwin and both were presented at the same time. evolution explains genetic similarities between organisms, gene that everyone has (including single celled yeasts RNA polymerase, tRNA, cytoskeletal proteins)

example of biological theory: cell theory

(Schwann and Schleiden, 1830's)

1- all living things are made of cells 2- The cell is the smallest living thing that can perform all the functions of life 3- All cells must come from pre-existing cells

homologous structures

structures that are similar due to shared ancestry

examples of homologous structures

dad and child both have deviated septum, inherited from ancestors. cat's heart, parts of the brain, same digestive tracts that go in the same order for shark, lizard, pigeon, cow, salamander. esophagus, stomach, intestine, liver.

vestigial structures

reduced versions of structures that were once functional. no longer used

vestigial structures examples

wing in flightless birds, pelvis in whales, reduced hind limbs in snakes, eye sockets in skulls of eyeless cave fish

What are model organisms

organisms related to organisms of interest. ex. drosophila

What are model organisms used for

don't have to test on humans, we can use mouse, rabbits, or monkeys because we have the same neurotransmitters and the same basic physiology. easy to take care of in lab, don't live long, reproduce quick.

Why is evolution considered a "core theme" of biology

its a unifying general explanation that explains diversity and change over time, helps us ask the "why" questions. why does this rhino have a horn, why dont humans hvae fur? helps to think from an evolutionary perspective

proximate

explains the mechanism of how something works. how stuff works.

ultimate

why? why is that trait there, how is it adaptive, and what is the benefit of it.

why does a cat's fur puff up when its scared? proximate explanation

the cat sees something scary, adrenaline in the cat's blood stream releases which causes the arrector pili muscle to contract. the hair stands up (how the fur stands up)

why does a cat's fur puff up when its scared? ultimate explanation

the cat is trying to look bigger when it responds to a threat, increasing its chances of survival. a dog might attack a cat that doesn't poof up with fur because it looks less intimidating

why do stressed leaves turn red? proximate

mechanism: transcription of some gene or some gene being turned on.

stressful conditions are sensed by the plant (buildup of sugars) triggers signaling cascades. the genes got turned on by the stress.

why do stressed leaves turn red? ultimate

red pigments act as a sunscreen whenever plants are exposed to more sunlight. they can build it and take it down whenever they need, its a metabolic red screen

why do humans have different skin color? proximate

melanin. all have same number melanocytes. At the protein level, some melanocytes make more melanin than others. you have an allele that helps you make more melanin

why do humans have different skin color? ultimate

why? the equator has the highest UV light, melanin absorbs UV very strongly. having high melanin near the equator is adaptive for protecting your folate and skin cancer.

Does every behavior or trait have an ultimate function that can be tested

no, not all ultimate explanations are testable. some adaptations might be directed towards species that are now extinct. ex. lancewood trees have 3 types of leaves it makes based on how tall it is. the baby trees have saw like leaves, when it gets to a normal height, it makes normal leaves. the height where the leaves start being normal is taller than the moa, so the moa wouldn't eat the saw like leaves. can't test this now because moa's are now extinct

What is convergent evolution/homoplasy/analogy

same structures evolve independently. also called homoplasy. the structures and analogus instead of homologus. they do the same thing from their own origins.

examples convergent evolution

ex. similar body plan of having tail, dorsal fins, pectoral fins evolved independently in mammals, reptiles and fish 3 times. this is analogy.

wings in bird, bat, and insect evolved independently so its analogus instead of homologous

analogous trait

wings in insects versus birds, they independently evolve a similar trait.

homologous trait

all inherited from a common ancestor ex. melanin

What are the oldest fossils on earth, and how old are they

3.5 billion years old. stromatolites (mineralized cyanobacteria mats)

When did the genus Homo first appear in the fossil record, and on which continent

2 mya in Africa

When did Homo sapiens first appear in the fossil record, and on which continent

200,000 ya in Africa

Which other species of Homo did Homo sapiens that left Africa hybridize with

neanderthal

When approximately did civilization and agriculture begin

~ 10 kya (thousand years ago)

For the vast majority of Homo sapiens history, which was practiced: hunter-gathering or agriculture

hunter-gathering

Where did agriculture originate

simultaneously in many places around the globe

Why didn't agriculture arise sooner?

corresponds with the end of the last glacial maximum. ice that went down to central north america. orange clay in the soil everywhere the glaciers didn't go (old clay that has lots of time to oxidize) in the north, there is grey clay that is recent

Why is agriculture so central to civilization and origins of modern society

the beginning of humans uncoupling themselves from their food sources being wild, they control them for the first time. breeding cattle and cows and planting crops to have a steady source of food.

Did writing originate BEFORE or AFTER agriculture was invented

after

Did modern religions (Judaism, Buddhism, Hinduism, etc.) originate BEFORE or AFTER agriculture was invented

after agriculture (<10,000 ya)

What did Aristotle contribute to the field of biology

dissected, drew, and observed a LOT of organisms, in very great detail (qualitative biology)

he was the first person to classify similar organisms

organized organisms into a hierarchy (least perfect to most perfect Scala naturae)

What is natural theology

nature is the direct product of a supernatural creator (God)

the Creator's plan could be revealed by studying and describing nature

nature = evidence of a creator

Provide one example of a natural theologian

gregor mendel

Who invented the microscope?

Robert Hooke

who later improved the microscope

Anton van Leeuwenhoek

aristotle was alive during which stage of human civilization

agricultural age

What is the difference between how food was produced before versus after the industrial revolution

before, agriculture used farmers and slaves which relied on muscle power. industrial relied on complex machines and fossil fuels

Put these events in order: Industrial Revolution, Agricultural Revolution, Middle Ages, Hunting-Gathering, the Enlightenment

Hunting-Gathering, Agricultural Revolution, Middle Ages, the Enlightenment, Industrial Revolution,

How were fossil fuels central to the industrial revolution

combustion of fossil fuels releases energy to do work. burning octane releases energy, hot air pushes pistons in engine

Name one example of a biologist who was a natural theologian

carl linneaus

Who was Linnaeus and what was his contribution to biology

natural theologian and founder of modern taxonomy. Developed binomial nomenclature

Developed our hierarchical systems of taxonomic categories (Kingdom, Phylum...)

Explain the difference between Lamarck's idea about how organisms change over time and Darwin's

Lamarck's idea involves changes that occur during the individual's lifetime (if i exercise a lot, my baby will have muscles). Darwin's idea involves changes in populations over time, as less fit individuals die, failing to pass on their genes. changes in individuals vs. changes in populations

How did Hutton contribute to the foundations of evolutionary theory

founder of modern geology (study of rocks). rock formations must be from processes that happened very gradually over a long period of time ("gradualism"), and that the earth must be older than 6,000 years old. proposed rock cycle

How did Cuvier contribute to the foundations of evolutionary theory?

paleontology (study of fossils), and comparative anatomy. observed that fossils occur in distinct strata. proposed that catastrophies such as floods changed the world which is why we have different creatures. digestive tract of human and whale are the same. cuvier, carved fossils

How did Malthus contribute to the foundations of evolutionary theory

philosopher and economist. he thinks ahead and states if population grows too fast, it outcompetes how much food we can supply. resulting in greater competition

In what period did human history experience rapid population growth? What caused the sudden increase

agriculture, then the industrial revolution. during time of industrial revolution, all food produced faster and populations growing.

Most scientists who contributed to the field of biology were alive during WHICH period in human history? (hunting and gathering, agricultural age, industrial age?)

industrial age

Who developed the theory of evolution by natural selection? (There are two people who contributed to this)

charles darwin & alfred wallace

What was the dominant view on the origin of humans at the time

public was interested but scientists need to count evidence and abandon hypotheses that aren't supported by evidence. darwin didn't say evolution, he said "descent with modification"

How is fitness quantified

number of offspring between phenotypes. more offspring = greater fitness. if the traits you inherit give you a higher chance of surviving & reproducing in a given environment, they tend to leave more offspring (too many kids & less hiding spots from predators in an environment is a disavantage)

What kinds of observations did Darwin make on his 5 year voyage on the H.M.S. Beagle?

collected insects, birds, skins. species in south america looked more like each other than the species in europe. the mockingbirds looked more closely related. same with the fossils. there were different species associated with different habitats (tortoises). proposed that a single species colonized an island(s). there were different selective pressures on different islands (predation can be escaped by the ability to blend in, competition for food) new species can result from different populations evolving to their different environments.

What is artificial selection, and what are two examples we talked about in class

humans have modified other species by selecting and breeding individuals with desired traits. ex. dogs were bred from wolves and brassica (cabbage, kale, and cauliflower are domesticated of wild mustard)

What is eugenics

the science of improving a human population by controlled breeding to have more desireable characteristics. superior and inferior individuals in a population, Nazi's wanted to make an "ideal" population through artifical selection.

What is social Darwinism

economic/capitalist idea. the market decides who's the fittest, we don't need to slow down or help the one's who are falling behind. shouldn't have to get taxed to share with the weaker, let the wealthy accumulate and share less with the less fit.

scenarios involving a Hardy-Weinberg assumption of your choice

1) No Mutation (throwing in new alleles in population)

2) No Migration (having individuals come and leave population)

3) Infinitely large population (equivalent to saying no genetic drift, small populations don't survive by chance)

4) No differences among genotypes being examined in survivorship or fecundity (no natural selection)

5) Random mating with regard to the character (gene) in question

What is the difference between microevolution and macroevolution

microevolution - changes in the allele frequency of a population but they aren't different species

macroevolution - changes that result in reproductive isolation from the parent population

If a mutation does not change the amino acid of a codon, which type of mutation occurred: silent, nonsense, or missense

silent mutation

silent mutation

change in the letter, but still the same amino acid

missense muation

when the change results in a new amino acid

nonsense mutation

a mutation that leads to a stop codon and you end up with a tinier protein

frameshift mutation

extra letters put in or removed can shift the reading frame

How does duplication or deletion of large portions of chromosomes (e.g. entire genes) occur

deletion - uneven crossing over and they don't line up perfectly, which deletes whole regions of the chromosome.

duplication - addition of extra regions of the chromosome

Does crossing over occur during mitosis or meiosis

meiosis

What are 2 examples of genes that have undergone extensive gene duplication in animals

olfactory receptors (organisms have hundreds of different receptors which arose via gene duplication) and globin genes (ancient genes found in plants such as legumes. have root nodules that take nitrogen from the air and make it to ammonia for fertilzier)

What is a pseudogene?

they are mutated but no longer work

Can mutations in somatic cells be passed on to offspring?

no, only mutations in the germline cells are passed down

age of the ______________increases risk of mutations in sperm

father

age of the _______________ increases risk of nondisjunction of chromosomes

mother

What is an example of a disease that children of older fathers are at an increased risk for

autism and schizophrenia

What is an example of a disease that children of older mothers are at an increased risk for

down syndrome

horizontal/lateral gene transfer

involves the transmission of DNA between different organisms (3 types are transduction by viruses, conjugation between bacteria, and transformation) you touching someone and passing DNA to them. how genes from different species arrive in the population

vertical gene transfer

when you have a baby, you pass on your genes to the baby vertically. mother to child

transduction by viruses

viruses move DNA from 1 organism to another.

Conjugation between bacteria

Bacteria connect via sex pilus to link with other bacteria even of different species and exchange plasmids

Transformation

Absorbing DNA from the environment into the genome. when cells or nucleus takes up free pieces of DNA

protein crucial for formation of the placenta in mammals

Syncitin

Syncitin proteins are from

viral proteins found in placental mammals

How do mutations in regulatory sequences affect gene expression

regulatory sequences include promoter, repressor and activator sequences, and all of the genes for the transcription factors that bind to the regulatory sequences. don't change the protein itself, only change how much its turned on or off

What is a proximate and ultimate cause for evolution of lactose tolerance in adults of some human populations

proximate - there was a point mutation in the enhancer region of the lactase gene (not the gene itself) that causes it to tbe turned on and stay on in adults

ultimate - people who are able to digest lactose survived in early times where formula was not introduced in some populations, over time this trait was passed down so some people have genes that can't digest lactose

gene flow

movement of alleles between populations

immigration (influx)

emigration (eflux)

Does gene flow between two populations make them more different or more similar or different to each other over time

more similar

Gene flow tends to increase genetic variation within populations and decreases variation

between populations (differences greater when separated but they go away once there's gene flow connecting them)

gene flow

new allele immigrated from another population

genetic drift

loss of alleles due to small population size due to bottleneck or founder effect

Why is genetic diversity important for survival of a population

more phenotypes lead to more survival as the environment changes (different color fur in rabbits to camoflauge)

True or False. A population that has undergone genetic drift will have MORE alleles per locus than a population that has not undergone genetic drift

true

bigger populations

drift happens slower

What are 2 other options, besides sexual reproduction, for passing on your genes

clothing/parthenogenesis

help your kin's offspring survive

What is a downside of cloning/parthenogenesis

all offspring is indentical

What is a eusocial organism?

cooperatively help raise the brood, have overlapping adult generations and division of labor

some examples of eusocial organisms

ants, bees, naked mole rats, termites

If eusocial organisms aren't passing on their genes through sexual reproduction, why do they participate in it

sacrifical behavior she's getting more fitness indirectly than if the sister's tried on their own (1 fertile queen)

Individuals tend to mate with individuals who are more UNLIKE themselves than chance would predict in (positive/negative) assortative mating

negative