EXAM 1 FLASHCARDS
how are natural selection and artificial selection the same?
both drive the evolution of species by selecting traits that are passed onto future generations
how are natural selection and artificial selection different
natural selection: driven by environmental pressures over long periods
- no specific goal
artificial selection: driven by human choices and can occur relatively quickly.
- goal-oriented, aiming to produce specific traits.
what is a common descent
all life can be traced back to a common ancestor
what is a paradigm shift?
fundamental change in the way we think about and study the origins of diversity of life and relationships between species (nature)
what three components must be present in a population in order for natural selection to occur?
- variation
- inheritance of variation
- differential reproductive success: more offspring are produced than can survive, those that are best adapted to their environment will produce more offspring and pass on more of their traits to the next generation.
what is uniformitarianism
the slow processes over long stretches of time can produce vast changes on Earth and the same geological process observable today have been acting throughout Earth’s history
what is the scientific method? what does it seek? and what is its order
Aims to explain the world based solely on natural phenomena (seeks explanation based on what is observed, tested, replicated, and verified)
- Define question
- Make observation
- Form hypothesis
- Make a prediction
- Conduct experiment
- Analyze results
- conclusions
what is James Hutton known for
Father of modern geology who theorized that the Earth is much older than we thought and stated that the Earth is continuously being formed and reformed (rocks are eroded away
what is the inheritance of acquired characteristics
Jean-Baptiste Lamarck, hypothesis that traits acquired during the lifetime of an organism are passed onto its offspring
what is evolution
Change in allele frequencies in a population over time (process of descent with modification)
what is descent with modification
evolutionary process by which species change over time
what is Charles Lyell known for and what did he argue
Noticed that the pillars of pozzuoli had been pierced by a marine bivalve and concluded that the columns had once been underwater and raised back up by volcanic eruption
Argued that these same processes have operated over long periods of time in a slow, gradual manner (patterns we see today were probs seen in Earth’s history)
what did Charles Lyell theorize
Theorized that the earths crust formed via small change over a vast period of time
What were observations Darwin made on his trip on the HMS Beagle and how do they relate to natural selection?
- Fossil evidence of giant armadillos
- Finches with different beaks
- Tortoises with different necks and shells
How characteristics of organisms change over time
Come from common ancestors
what was Thomas Malthus known for
English economist who argued that the human population is growing faster than food production leading to the competition os resources
what was Jean-Baptists Lamarack known for (give an example)
he was the first to publicly suggest that species changed overtime and explained that the mechanism of change was the inheritance of acquired characteristics to offspring (Ex: giraffe neck)
what was Erasmus Darwin known for
Charles Darwin grandpa who classified facts about animals and argued that all life descended from a “single living filament”
what did Erasmus Darwin originally hypothesize
Initially hypothesized that humans initially walked on four limbs and that we descended from primate species (radical at the time)
what is Charles Darwin known for?
best known for his theory of evolution by natural selection (On the Origin of Species)
what was Alfred Russel Wallace known for?
English naturalist, surveyor, collector who noted differences between species in lands that were geographically separated in SA and SE Asia. 1858: He wrote his idea of natural selection on a malaria fever dream and sent his findings to Darwin. Published paper with Darwin about thoughts.
what were Charles Darwin’s two great insights
- Natural Selection: the environment selects on variation in the traits of individual organisms, because some variants are more successful than others at increasing the probability of survival and reproduction
- Common Ancestry: all species have descended from one or a few common ancestors. Species that share a recent common ancestor tend to resemble one another in many ways
what is natural selection
over time, beneficial traits become more common in a population due to increased survival and reproduction of individuals that have those traits
what is artificial selection and what are some examples
Process of human directed selective breeding aimed at producing a desired set of traits in the selected species (ex Darwin and strawberries and pigeons)
Human-driven analog to process of natural selection
what did humans rely on prior to the scientific method
mystical and spiritual explanations
what is the quote by Theodosius Dobzhansky
“Nothing in biology makes sense except in the light of evolution”
why was the voyage of the beagle so important and how long was the trip
1831-1836
the trip provided Darwin with the insight and observations that led him to write On the Origin of Species
which of the following question can be answered by the scientific method
A. is the starry night the most beautiful painting ever made
B. does drinking coffee on a daily basis result in a lower risk of heart disease
C. what is the song Stairway to Heaven
D. Is there life after death?
B. does drinking coffee on a daily basis result in a lower risk of heart disease
what did Jon Snow do during the cholera epidemic of 1854
he pinpointed the water pump he thought was the source of cholera and removed the Broad Street’s water pump handle
According to Lamarck’s theory of evolution, how did he propose that traits are passed on to offspring?
through passing along traits that were acquired during the lifetime of the organism
What observation led Charles Lyell to conclude that the columns of Pozzuoli had once been underwater?
the marble of pillars had been pierced by a marine bivalve
What was the central argument of Thomas Malthus in his ‘Essay on the Principle of Population’?
Human population growth will outpace food production and lead to limits on further population growth
what three observations helped support Darwin’s ideas on evolution
- Earthquake in conception- in the Valdivia region of Chile place of seafloor was lifted 9ft and exposed to air, which reminded Darwin of pillars and how they related to past times. Marine fossils were found in the Andes Mountains
- In South America fossils of extinct creatures such as the Glytodon were discovered and were giant relatives of armadillos. This helped Darwin develop this theory of evolution.
- Turtles, land/marine iguanas, and finches on the Galapagos island showed evolution and aided him in forming his ideas of natural selection.
What action did Alfred Russel Wallace take in 1858 that contributed to the theory of evolution by natural selection?
he wrote up his idea of natural selection during malarial fever dream
what was similar to living armadillos provided evidence for evolution.
glyptodont fossils
what related species were each very well-adapted to their specific niches, providing evidence for natural selection.
Galapagos finches
natural selection occurs when
beneficial traits become more common in a population because individuals who possess them survive and reproduce better than other individuals in the population
Artificial selection differs from natural selection because
in artificial selection, humans determine which traits are beneficial in a population and which are not
evolutionary thinking = ?
paradigm shift
what type of neck and shell did turtles who lived in humid areas with abundant vegetation have
short neck and dome shell
what type of neck and shell did turtles who live in a drier areas where vegetation was less abundant have
long neck and saddle shell
Darwin began introducing natural selection via what
artificial selection
what is LUCA
the last universal common ancestor
what is so important about the year 1859
Darwin’s book “On the Origin of Species” came out
the joint Darwin-Wallace paper came out in 1858 and comprised of four parts what were they?
- an introduction by Lyell and Hooker
- two articles by Darwin, each with a separate title
- one article by Wallace, also with a separate title
(UNITED UNDER 1 PUBLICATION)
What years were Jean-Baptiste Lamarck active?
1744-1829
What years were James Hutton active?
1726-1797
What years were Charles Lyell active?
1797-1875
What year was the “Essay on the Principle of Population” published and who was the author
Thomas Malthus and 1798
What years were Erasmus Darwin active?
1731-1802
What years were Charles Darwin active?
1809-1882
What year was the “On the Origin of Species” published and who was the author
Charles Darwin and 1859-theory of natural selection
What years were Alfred Russel Wallace active?
1823-1913
What year did Alfred Russel Wallace write up his idea of natural selection?
1858
What is an example of variation?
different mice in a population having different coat colors: If all the mice had the same coat color natural selection could not occur; without variation, there is nothing for natural selection to select (needs to be a variation of traits among offspring)
How can variation in phenotypes arise?
through variation in genes alone, variation in environment alone, or through a combination of both.
What will occur if there is no genetic inheritance?
if traits were not passed down genetically, there would be no natural selection to ensure that beneficial traits increase in frequency or that less beneficial traits decrease. As a result, the distribution of trait varieties would remain largely unchanged from one generation to the next
What is an example of inheritance?
EX: offspring tend to resemble their parents so lady bugs that are red will tend to have red offspring and ladybugs that are yellow tend to have yellow offspring
What is an example for Differential Reproductive Success?
mice in sand: one with a cream coat one with a dark coat. Dark coat is eaten because more visible to predators compared to cream coat and only cream coat live and have babies….tons of babies that have cream coats in next gen (best fit trait)
What years were Thomas Malthus active?
1766-1834
How are adaptations and exaptations different?
Adaptations: an inherited trait that makes an organism more fit in its abiotic and biotic environments and that has arisen because of the direct action of natural selection for its primary contemporary function
Exaptations: trait that serves one purpose today but which evolved from a trait that served a different function in the past
What is the original source of variation in populations? what is an example? what do mutations do?
mutations (ex: antibiotic resistance)
mutations can change the phenotype an can be neutral or bad or good
Provide some examples of evolutionary trade-offs.
Peacock Feathers: those with larger, brighter feathers have more eye spots and are more attractive to females to reproduce BUT the larger these are the worse they fly and are more visible to predators
Ancient Arthropods
- Small clutches of large eggs: it takes a lot of energy to make these eggs that can better survive in the environment. Large eggs = fight off predators easily when fully grown 😁 but small clutches = only have few offspring to pass on their genes 🙁
- Large clutches of small eggs: Small eggs = not able to fight off predators and win as much. Large clutches = there’s a greater chance that at least a couple will survive if predator attacks
Sickle Cell Anemia
- both hemoglobin = death by malaria
- heterozygous (one sickle cell and one hemoglobin mutated gene) = resistance against malaria (survival advantage)
- both sickle cell anemia = death by SCA
Natural selection does not result in a perfect organism. Why not? what are the constraints?
process of natural selection operates on physical structure in the material world, and as such is constrained by physical and mechanical laws. This process has no way of anticipating the future nor can it plan ahead. Selection favors changes that are immediately beneficial, not changes that may be useful sometime in the future.
- Lack of genetic variation
- Physical constrains
- Developmental constraints
- Natural selection lacks foresight and environment is always changing (cant keep up)
- Ex: elephant cant get small legs
- “Unintelligent design”
What characteristic was selected for in the fox farm experiments?
tameness: calmest, most pro-social-toward human animals
what is fitness and how is it measured
expected reproductive success of an individual who has trait/allele relative to other members of a population (measured by the number of offspring an individual has)
what is the norm of reaction
a curve representing phenotype for a particular genotype given a range of environmental conditions.
- a range of given phenotypes in a given environment (ex: height)
what is an adaptation
inherited trait that increases an individual’s fitness in its abiotic and biotic environment. Become more common in populations via natural selection for its current primary function (ex: cactus)
what is an exaptation
a trait that currently serves one function today, but which evolved from a trait that served a different function in the past
what is a genotype and what are 2 key pieces of information
Genotype: an organism’s genetic makeup (specific alleles or variants of a gene an organism has.
- Interacts with environment to produce phenotype
- Genotype doesn’t lead to just one phenotype, but instead multiple phenotypes that can be shown in a norm of reaction.
what is a phenotype and what can affect it
set of observable characteristics of an individual resulting from the interaction of its genotype with the environment
- Both nature and nurture affect phenotype
what is domestication syndrome
suite of characteristics including floppy ears, short, curly tails, juvenilized facial and body features, reduced stress hormone levels, mottled fur, and relatively long reproductive seasons
what is the neural crest cell hypothesis
Proposes that selection for tame behavior results in a reduction of the number of neural crest cells migrating to diff parts of the body during embryonic development. which subsequently leads to changes in fur coloration, facial structure, the strength of cartilage (floppy ears, curly tails, etc.), hormone levels, length of the reproductive season, and more.
what is flight distance
measures how far an animal will flee from a threat before taking action (dogs with a shorter flight distance would get closer to humans for their food). an animal’s willingness to take risks when threatened
what is evolutionary trade-off
constraints may prevent simultaneous optimization of two traits, or different aspects of an individual trait. (There is a positive benefit to the trait, but also a negative at the same time)
What were Belyaev’s two hypotheses?
- The early stages of ALL animal domestication events involved human selection to choose the calmest, most prosocial-toward-human animals (tameness). IN OTHER WORDS: CHOOSE ANIMAL WHO IS THE MOST TAME WITH RESPECT TO HUMANS.
- All of the traits in the domestication syndrome were somehow or another, though he didn’t know how or why, genetically linked to genes associated with tameness.
Who was Lysenko? Include at least three major facts.
A pseudo-scientific charlatan who was a member of the Soviet Union’s Communist Party leadership (under Stalin) which attempted to glorify the avg. citizen.
- falsified experimental data in order to claim he had produced grain crops that produced high yields in the coldest years, and continued to do so for generations to come.
- began a crusade to discredit work in Mendelian genetics. He denounced geneticists, both overseas and the Soviet Union. He tried to shut down the Institute of Cytology and Genetics, which included Belyaev’s experiments.
- placed in charge of all policy regarding the biological sciences in July 1948. Gave a speech in 1948 which discredited Mendelian genetics, resulting in subsequent firing of thousands of Soviet geneticists (and likely the jailing and murdering of others).
Who made sure that Lysenko didn’t shut down the fox farm experiments
Khrushchev’s (supporter of Lysenko) daughter Rada had trained as a biologist and understood Lysenko was a fraud. She managed to convince her father to let the Institute of Cytology and Genetics remain open
The suite of traits seen in many domesticated animals that is collectively known as the “domestication syndrome” includes which of the following? (multiple answers)
A. floppy ears
B. short reproductive seasons as compared to wild counterparts
C. increased stress hormone levels
D. curly tails
E. juvenile facial features (large eyes, reduced teeth)
A. floppy ears
D. curly tails
E. juvenile facial features (large eyes, reduced teeth)
T/F: Trofim Lysenko, who became director of the Institute of Genetics of the Academy of Sciences of the U.S.S.R, was a trained scientist known for his replicable experiments on agricultural crops.
FALSE
The neural crest cell hypothesis suggests that the observed suite of characteristics that appear in animals that display the “domestication syndrome” are a result of
a reduced number of neural crest cells migrating to different parts of the body during embryonic development.
Belyaev hypothesized that which of the following about animal domestication events in human history?
a. Domestication events have involved human selection for the animals that are most aggressive toward other animals.
b. All traits in the domestication syndrome were genetically linked.
c. Domestication events have involved human selection for the animals that are most tame with respect to humans.
d. all of the above
e. B and C
e. B and C
- All traits in the domestication syndrome were genetically linked.
- Domestication events have involved human selection for the animals that are most tame with respect to humans.
T/F: Selection for tameness alone in foxes can lead to the traits associated with the domestication syndrome.
TRUE
T/F: The changes observed in the Belyaev fox populations are an example of evolution driven by artificial selection.
TRUE
How did Belyaev and his research team determine which foxes would be allowed to breed / parent the next generation of foxes?
they selected the foxes that were in the top 10% on a scale measuring tameness.
Which of the following can be concluded based on Belyaev’s experiments?
a. Domestication events require at least 1,000 generations.
b. Selection for tameness alone can lead to domestication syndrome in foxes.
c. The neural crest cell hypothesis can explain the phenomenon known as domestication syndrome.
d. all of the above
b. Selection for tameness alone can lead to domestication syndrome in foxes.
By generation 15, which of the following traits had emerged in the fox population? (Check all that apply.)
A. foxes wagged their tails when humans approached
B. floppy ears and curly tails
C. foxes licked the hand of experimenters
D. stress hormone levels increased
E. serotonin hormone levels decreased
A. foxes wagged their tails when humans approached
B. floppy ears and curly tails
C. foxes licked the hand of experimenters
Which key things did Lysenko do?
- He was a member of the Soviet Union’s Communist party under Stalin.
- He falsified experimental data in order to claim he had produced grain crops that produced high yields in the coldest years, and continued to do so for generations to come.
- He tried to shut down the Institute of Cytology and Genetics, which included Belyaev’s experiments.
- He gave a speech in 1948 which discredited Mendelian genetics, resulting in subsequent firing of thousands of Soviet geneticists (and likely the jailing and murdering of others).
Which features of a cactus is an adaptation to its environment favored by natural selection?
- sharp spines to deter herbivores
- flowers to attract pollinators
- waxy cuticle to prevent water loss
match this definitions with these terms: variance, inheritance, differential reproductive success
Some beetles were brightly colored, some were dull in coloration.
brightly-colored individuals are bitter and predators avoid them, resulting in better survival and passing along of more genes
beetles resemble their parents in coloration
Some beetles were brightly colored, some were dull in coloration. = VARIATION
brightly-colored individuals are bitter and predators avoid them, resulting in better survival and passing along of more genes = DIFFERENTIAL REPRODUCTIVE SUCCESS
beetles resemble their parents in coloration = INHERITANCE
For traits to evolve by natural selection, individuals must experience differential reproductive success. This means that
individuals with certain traits are more successful than others in the population at surviving and reproducing
Antibiotic resistance evolves quickly because
antibiotics impose strong selection for resistance
T/F? Individual organisms may evolve (in a biological sense) during the course of their lives.
FALSE (populations are the ones that evolve)
How did the study sites differ in the mountain streams for guppies?
the sites above the waterfalls had lower predation rates than the sites below the waterfalls
What was observed when guppies were moved from high to low-predation sites?
females produced fewer offspring that were larger
What statements correspond with the sickle cell anemia example within the slides?
- incidence of the sickle cell allele is correlated with the incidence of malaria in Africa
- Sickle cell allele has been selected for in malaria-prone regions because it carries a survival advantage against malaria
- individuals that are heterozygous at the Hemoglobin locus (one normal, one sickle cell allele) have resistance against malaria
Natural selection is a process that results in
evolution of populations
what are 4 key points to remember about mutations and how they generate variation
- they are random
- mutations can change phenotype
- many are neutral or deleterious (confer negative result = less fit)
- some are positive for fitness
