Chapter 16: Evolutionary Biology Flashcards

Question

Evidence regarding evolution

Answer 1

- "just a theory" - debates on how evolution took place - gaps in fossil records = work-in progress, might not have the exact lineage (which actually makes it look more believable) - continual refining of evolution (like all good sciences) - Darwinism is rejected bc he didn't know about genetics (which acc makes his theory stronger) - misconception: its not observable or testable (it is through CRISPR) - Animals: Guppies, Finches, Fruitflise, Sticklebacks {MODEL SYSTEMS}

Answer 2

CRISPR: alter genotype to determine if its helps with fitness EPIGENETICS; change in phenotype by genotype INDIRECTLY

Answer 3

- we evolve slowly and have factors that affect evolution such as culture I.E. CULTURE AFFECTING EVOLUTION Spices, which have antimicrobial properties, may have helped humans adapt to warmer climates where food spoilage was more common

Answer 4

- antibiotic resistance in bacteria is a consequence of evolution by N.S.

Answer 5

- unifying theme for all life-sciences - medical applications (HIV, antibiotics, etc.) - global warming issues (breeding times; if breeding times is not optimal for food source then there becomes a genetic barrier for who opts in/out) - industrial applications (pesticides) = changes in spray formula so you're not selecting for 1 phenotype

Answer 6

SOCIAL DARWINISM - "survival of the fittest": creates oppression of ppl - Division btwn evolution and religion; leads to immoral behaviour (animal like) - the mismeasure of man (by Stephen j. Gould)

Answer 7

- all life on earth descended from a common ancestor and that all populations of organisms change over time

Answer 8

over many generations

Answer 9

adaptation and increased fitness

Answer 10

- from darwin - traits that help organisms reproduce (i..e colourful feathers on birds)

Answer 11

- from darwin - how related diff species are to each other

Answer 12

- certain traits can be inherited by offspring (taken advantage of by breeders) - humans (breeders) selectively breed for desired characteristics; enhancing those traits in future generations {selective breeding} Artificial Selection= human mediated evolution

Answer 13

- corn is originally from a Mexican grain (teosinte), but farmers selected the largest, easy to eat, and exposed kernels on teosinte which is how we got the corn we have today

Answer 14

- environmental factors: limited food + habitat, predation, competition, disease - individuals w/ heritable traits that provide an advantage in obtaining limited resources and avoiding predation/disease will have a better chance at reproducing and lead to population level changes - differences are created by differences in DNA and can be inherited = naturally selected advantage in their habitat

Answer 15

- what's fit now might not be in 5 years - depending on selection pressures

Answer 16

COMPOSITE - finding food - mating - survival - reproduction *not just based on 1 trait, several traits influence fitness*

Answer 17

- group of interbreeding individuals of a species that live together in a specific place - individual organisms don't evolve in their life (we are byproducts of previous selective pressures), the unit upon which evolution acts (relative measure) is POPULATION

Answer 18

1) variation amongst individuals in a population 2) heritability of that variation - i.e. there are some traits aren't genetic but are caused by environment such as orange fur caused by orange pigment in food

Answer 19

Early evidence from Island population observations - each island= isolated habitat w/ conditions that are distinctly diff w/ diff selective pressures GALAPAGOS - prime example - four mockingbird species are all descended from a common ancestor but have adapted to diff environments (Darwin studied these not finches) theory: population of one mockingbird species came and colonized most of islands around the same time = proof for descent w/ modification (changed over time w/ diff selective pressures and w/ a common ancestor)

Answer 20

species found nowhere else on earth i.e. the mockingbirds Darwin studied - they are morphologically (body traits and types) distinct

Answer 21

ADAPTATION: inherited aspects of an individual that make well suited to thrive in a particular environment - species experience diff environments leading to N.S. which favours diff traits differently depending on environment *predicted that species become better adapted to specific environments over time (such as the birds)* -- i.e. birds will adapt their songs to be more transmissible to mates depending on environments

Answer 22

- variation in DNA sequences gives rise to individuals within a population exhibiting different traits - DNA sequence of any individual may be different because of MUTATIONS MUTATIONS: random, heritable changes in DNA sequence - may come from errors in DNA replication, or agents

Answer 23

- some individuals have mutations that may be sitting in 1 environment but become in a changing environment - from genome

Answer 24

1) moth populations - predation pressure (birds being able to see white moths easier) and changing environments (industrial rvln) caused black moths to become dominant in population as they camouflaged better in their environment 2) red vs white salmon - sexual selection - in some populations, they prefer brighter red males *Found locus of gene that dictates if they'd be red/white: based on process carotenoids*

Answer 25

- using organisms w/ short generation times can help us conduct studies - allowing for direct comparisons btwn ancestral and evolved populations i.e. E.COLI AND CHANGE IN TEMPERATURE - scientists wanted to determine if e.coli (for many generations) would adapt to a temperature that's lower than their og optimal? - they saw relative fitness was greater than 1= population (in 20-35 degrees) still grew faster than ancestral pop. so, the e.coli adapted but with even higher temperatures, the new generation did not do as well as ancestral generation (37-40 degrees)

Answer 26

- we can attribute the exact function to genome (displayed w/ Manhattan flock, dots=cause particular phenotype) example: fish losing armour - marine stickleback need armour based on their oceanic environments but freshwater ones don;t - specific functional genes (Pitx 1) can be linked to fitness-related traits (pelvic spines) = selection on transcription, freshwater sticklebacks don't produce Pitx1 bc its costly to produce armour, they have the gene though - no armour was preferred because less energy expenditure and dragonfly larvae (predator) in lakes prefer prominent spines - led to increased fitness

Answer 27

- rate of change within a population is determined by GENERATION TIME (avg difference in age between a parent and its offspring)

Answer 28

- made a space for women in evolution - studied Darwins finches on the islands= most important dataset in science

Answer 29

1) acquired traits are inherited 2) fixed species (natural theology)

Answer 30

Darwin - not the only person; Wallace also did at the same time but by analyzing beetles

Answer 31

- aristotle - carolus linneaus - lamarck - ofc Darwin

Answer 32

- Aristotle created a ladder like classification of nature: SCALA NATURAE = problem for evolutionary biology - because it gave perception that humans were the end-result and he had "lower-class animals" IMPACT: NATURAL THEOLOGY europeans had merged Aristotle's classification system w/ biblical account of creation to arrive at a view of the natural world where (1) organisms had been specially created by God (2) species could never change or become extinct (3) new species could never arise

Answer 33

- observations of patterns in organisms - geological evidence of earth - fossilized life similar to but distinct from modern organisms

Answer 34

- swedish botanist - classified all organisms via binomial species classification system (TAXONOMY; branch of biology that classifies organisms) - similar-looking organisms are grouped together and organized into broader, more inclusive categories *first one to actualize what Darwin was saying about biology*

Answer 35

- named plants, based on appearance and growth form of a plant + its use to humans I.E. soapberry - derived from word meaning to "froth" because its extracts can be whipped as froth

Answer 36

- French naturalist Perfect Principle: simple organisms evolved into more complex ones, moving up *scale of nature* - microscopic organisms were replaced by spontaneous generations, where simple forms of life were believed from arise non-living things - ACQUIRED TRAITS ARE INHERITED - characteristics acquired during and organisms lifetime can be passed on to future generations - i.e. giraffe would grow a longer and longer neck during its lifetime to get to trees and then pass those traits to its offspring

Answer 37

(1) Organisms do not appear through spontaneous generations (non-living things can't create life) (2) Although muscles can grow larger through continued use, organisms can't evolve fundamental physiological changes during their lifetime, and any physical changes acquired during an organisms life are not passed to offspring

Answer 38

- species change over time

Answer 39

in 1831 he went on a voyage around the world on HMS Beagle - primary purpose was to map the coast of South American

Answer 40

- Lamarck believed that as wading birds stretched their legs keep their bodies while feeding, successive generations would have progressively longer legs

Answer 41

major observations came from 3 observations of study: (1) Geology and fossil record (2) Geographic distribution of species (animals in Australia aren't the same in France) (3) comparative morphology of species (animals come from all diff parts of the world but still have similar elements) i.e. of (3) : African Ostrich has similar elements to Australian Emu and South American rhea

Answer 42

- underwent earthquake in Chile - climbed up Andes and discovered fossil shells of marine organisms (indicated earth is rlly old and species CAN go extinct, some fossils looked nothing like living creatures, but others resembled living species (ex. glyptodonts and armadillos) = Lyell was right (published Principles of Geology): the geology of the Earth is not static; it changes over time - Darwin hypothesized that life can do the same

Answer 43

extant: alive today extinct: gone today

Answer 44

- studies of the worldwide distribution of plants and animals = biogeography - raised many q abt the number of species created abt God and where they'd fit on scale of nature

Answer 45

- Biologists began to compare morphology of organisms and discovered interesting similarities and differences I.E. human arm, flippers of seals, and wings of bats differ in size, shape, and function but have very similar underlying structure = LE COMTE DE BUFFON PROPOSED VESTIGIAL STRUCTURES

Answer 46

- useless parts observed today: must have functioned in ancestral organisms - Buffon proposed that some animal must have changed since creation

Answer 47

- Buffon proposed that some animal must have changed since creation - Darwin proposed that it was because all the organisms are related, they look similar because they are descendants of an ancestor they all shared (SHARED HOMOLOGY)

Answer 48

- similarity present in a group of organisms - to Darwin, morphological similarities among species suggested common ancestry

Answer 49

- body-shape of sharks (fish) and orca whales (mammals) fish ≠ whales - both streamlined shapes, powerful tails, and short fine/flippers (same elements in diff forms) - homoplasty= opposite of homologous

Answer 50

Kiwi: flightless, tiny useless wings - as it gets more ancient the wings would go away - wings are costly to produce, use that energy to survive (these kiwis outlive the other ones) Boa: tiny remnant hind limbs (spur) Humans: Goosebumps to make us look bigger with hairs sticking up

Answer 51

- naturalist - arrived to similar conclusions as Darwin about species changing over time after extensive research on SE Asia - studied beetle specimen - Wallace conveyed his ideas about evolution to Darwin via letter, Darwin quickly put together *The Origin* after this, but kept Wallace's letter w/ it (Darwin's ideas were still more thorough)

Answer 52

- Thomas Malthus (political economist) - humanity was destined for disaster based on human pop. increases exponentially as gains in agriculture was steady - addressing declines in living conditions; birth rate needs to be controlled to avoid poverty and starvation INFLUENCE/IMPACT: - Darwin +. Wallace observed that the potential of species to reproduce is far greater than the number of offspring that reach adulthood - no species seems to reproduce to their full potential indicates that offspring are under constant "STRUGGLE FOR EXISTENCE" - organisms are in competition w. one another for limited food and other resources they have to escape predation and they have to survive often unfavourable environments

Answer 53

- unified theory of evolution - integrated data from biogeography, comparative morphology, comparative embryology, genetics, palaeontology, and taxonomy in an evolutionary framework - natural selection is the primary mechanism of evolution, but its not the only mechanism - change happens gradually, and mutations don't play as big a part in evolution as was once believed

Answer 54

- women are less evolved than men (from textbook) - N.S. is the primary mechanism of evolution BUT NOT THE ONLY ONE - change happens gradually, and mutations don't play as big a part in evolution as was believed

Answer 55

microevolution: small-scale genetic changes that population undergo, often in response to shifting environmental circumstances (small evolutionary shift in size of the bill of finch) macroevolution: larger-scale evolutionary changes observed in species. Comes from gradual accumulation of microevolutionary changes.

Answer 56

Postulate: conditions necessary to support a theory (1) Individuals within populations are variable for a particular trait (2) Variations among individuals are heritable, at least in part, passed from parents to offspring (3) In every generation, some individuals are more successful at surviving and reproducing than others (4) Survival and reproduction of individuals is NOT RANDOM If these are supported then... = Individuals with the most favourable variations (survival and reproduction) are naturally selected.

Answer 57

Darwinian Fitness- ability of an individual to survive and reproduce in its environment Adaptation: trait or characteristic that increases its fitness relative to those w/o trait. = Not every trait is adaptable, traits have 2 be tested

Answer 58

- complex of birds from central or South American common ancestor 2.3 MYA= mutations, DNA, and molecular clocks are used to date a common ancestor and its relation to species

Answer 59

- 1 species of Darwins Finches - good to study because: few of them migrated off/on; populations were easy to manage - each one has a unique band; identifiable - 4.5 years=generation time - primarily seed eaters (bigger beaks, larger seeds) MALES (black) VS FEMALES (beige) = sexually selected

Answer 60

**(1) Is the finch population variable (variation in phenotype?)** -histograms show varying frequency of beak depth trait = yes, there is variation

Answer 61

**(2) Is some of the variation heritable?** - heritability of a trait is defined as the proportion of variation observed in a population that is due to variation in genes (by definition, anything that's not genetic is due 2 the environment) BROAD-SENSE HERITABILITY EQN = VG/VP = VG/(VG+VE) VP= variation in population VG= variation due to genetics VE= variation due to environment - varies between 0 (all environment) and 1 (all genetics) FOR FINCHES: - line of best fit (minimize distance between on orthogonal (diagonal) scale) - strong relationship between parents and kids = heritable (for beak depth trait) *parent-offspring regression* SPECIFIC GENES RESPONSIBLE: - genetic basis of beak development - growth factors (embryonic stages) - bone morphogenic protein 4 (BMP4)=affects shape/size of beak larger beak (more of it = bigger beak) - use mRNA staining to look for it (fluorescence) - BMP4 and relative beak depth= strong relationship

Answer 62

**(3) Variation in survival or reproduction?** - strong selection pressures alter the population/fitness of finches i.e. weather affecting food creating pressures over beak size - when seeds got larger and harder, environment selected for larger beaks that could open them (plants keep h2o to survive)

Answer 63

**(4) Survival & Reproduction are non-random?** - 1/2mm shift showed that selection pressures favoured larger beaks (larger, tougher seeds) - as environment fluctuates and small, softer seeds become common, smaller beaks will be favourable again = as environment changes, selection pressures change

Answer 64

1) NS is not forward looking (no end-goal, just adapted to previous environment) 2) NS is nonrandom (but not progressive) - bullet in car analogy 3) Fitness is not circular - environment drives fitness - requirement: heritable variants do better than others, as opposed to random ones 4) Selection acts on individuals - not for the good a species -altruistic behaviours 5) NS acts on individuals 6) Traits need to be heritable (seen w/ regression line) - heritability estimate is high (steep line; will get into pop within 2-3 gens) or low (flat line; even w/ strong selection, won't permeate population fast) 7) New Traits can evolve - artificial selection w/ corn - big changes in short time due to strong selection pressure 8) NS doesn't lead to "perfection" - big body dilemma for fish

Answer 65

- if N.S. doesn't act for the good of a species? Altruistic Behaviour: helping someone at a cost to yourself/at your expense - happens because of kin selection (protect relatives w/ same genes) i.e. Prairie Dogs: alarm call could alert predators but it protects relatives, they will only do it with relatives

Answer 66

- big bodies are better for swimming away from predator= selected upon BUT - big body fishes have a large gonapodia, which hinders their swimming =CONCORDED TRAIT (big body and big gonapodias are tied together) = trade off w/ traits *multi-dimensional look at fitness* - there is a physical limit but no peak/perfection

Answer 67

1) How was variability generated in populations - mutations (chromosomes, locus, alleles) 2) How were "variations" passed onto offspring - heritable via DNA 3) Age of the earth (Lord Kelvin's Calculations) - earth is very old: geological evidence of evolution

Answer 68

integrating genetics w/ Darwins 4 postulates

Answer 69

1) As a result of mutation creating new alleles, segregation, independent assortment, and shuffling alleles into new combinations, individuals within populations are variable for many traits 2) Individuals pass their alleles to their offspring intact (1 locus w/ 2 alleles and you either get A or B allele) 3) NO CHANGE; In every generation, some individuals are more successful at surviving and reproducing than others 4) The individuals that survive and reproduce are those w/ the alleles (or combinations of alleles) that best adapt them to their environment

Answer 70

Additive genetic effects involve independent contributions of alleles to a trait, while non-additive effects arise from interactions where alleles influence each other’s expression.

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Chapter 16: Evolutionary Biology Flashcards

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