Lec 1 Flashcards
What is Science?
“Systematic study of the structure and behavior of the physical and natural world through observation and experimentation”
Science is based on experimentation and observation of _________________
Natural phenomena
Science is based on _____________ - hypotheses that can be shown to be NOT TRUE based on data
Falsifiable hypotheses
What explanations for phenomena are beyond the scope of science?
Supernatural or faith-based explanations
Why is it incorrect to say it’s “Just a Theory”?
Scientific theories must be based on supported hypotheses (facts)
Scientific theories must be falsifiable
Scientific theories are the most reliable, rigorous, and comprehensive form of scientific knowledge
Scientific theories are built on MOUNTAINS of theory and MUST be falsifiable; VERY rigorous
Theory vs. scientific theory
Theories are generalized explanations of how things work
Scientific theories are built on mountains of data
An hypothesis is:
A testable idea
Theory
In every day life, it’s used as “opinion, hunch, or guess”
Scientific Theory
Supported by many facts; must be supported by multiple tests
Scientific Law
NOT the same as Scientific Theory
Theory explains the why, Law explains the WHAT
Well-known scientific theories
Theory of Earth Rotation (1613)
Theory of Blood Circulation (1628)
Theory of Gravity (1687)
Cell Theory (1839) [1891*]
Germ Theory of Disease (1020*) (1856)
Theory of Evolution (1859)
Theory of Plate Tectonics (1920)
Theory of Relativity (1920)
Evolutionary Theory
1859
General explanation for biodiversity on earth supported by evidence
Origins and Development of Evolutionary Theory
Darwin was not the first to propose the idea that species can change through time
His Theory of Descent with Modification by Natural Selection was hugely influential in the development of the modern Theory of Evolution
What is evolution?
Evolution is change over time… specifically the change in ALLELE frequencies over time
Darwin did not initially describe evolution as changes in allele frequencies. He conceptualized it as changes in phenotype - the outward appearance of an organism.
Evolution is the foundation of out understanding of __________
ALL biological processes
“Nothing in biology makes sense except in the light of _______” - ________
Evoltuion
Theodosius Dobzhansky
Scientific Questions asked by pre-Darwinian thinkers
What separates science and mythology?
How should scientists draw conclusions about the natural world?
How does the natural world change?
Why is the world filled with a diversity of life forms?
Where do species come from?
Why are organisms so well-suited to their environments?
Methodological Naturalism
Every human culture has creation myths to explain how the wordl came to be
Greek philosophers such as Anaximander (610-546 BC) attempted to develop ideas of a natural world driven by physical laws
These were driven by PHYSICAL LAWS
Methodological Naturalism: Anaximander’s Cosmology
The heavenly bodies (planets) are not divine
Suggested that the sun, moon, and stars are physical objects
Stated that heavenly bodies rotate around the earth (not true)
Set the stage for natural, rather than supernatural, explanations for phenomena
Power of Methodological Naturalism
Natural explanations for natural processes are testable, because we can observe and manipulate these processes
Supernatural explanation are not testable because supernatural causation cannot be observed or manipulated
We call it “methodological” because it provides a method for seeking scientific explanations of the world
These features separate science from mythology
Hypothesis Testing
Aristotle (384-322 BC) introduced the idea of HYPOTHESIS TESTING
This means principles must agree with facts - not the other way around
We should be able to observe and manipulate the processes underlying out hypotheses
In facts and principles do not agree, we must re-evaluate our principles
Principles MUST agree with facts; if a fact contradicts a principle, you change the hypothesis, NOT the fact
Basis of Hypothesis Testing
- Scientific hypotheses require causal explanations and must be rigorous
- Scientific hypotheses must be falsifiable; must be able to show that they are not true
- Hypothesis testing requires a control
- Hypothesis testing must be repeatable
If we can’t get the same results in other tests, it is not a good hypothesis
A hypothesis is a _______ based on the knowledge obtained while formulating a question
Conjecture
Control
Un-manipulated condition
Origins of the scientific process
Testing hypotheses and the application of natural and mathematical laws and logic allow thinkers to move from facts to general principles
Ibn al-Haytham (965-1040AD), an Arab mathematician and philosopher, is often considered the first to employ systematic approach to varying experimental conditions in his studies of optics
Classic test of hypotheses about origin of life
Ideas of spontaneous generation of life existed in the ancient world and persisted for thousands of years
Francesco Redi used a modern experiment to test this idea in 1668
Hypothesis: Flies generate spontaneously in meat
Predictions: If hypothesis supported, there should be flies in all treatment jars
There was an idea that flies spontaneously generate out of meat because any time a piece of meat is out, flies appear on it quickly
Flies only appeared in open containers, maggots, too
Which of these is NOT a testable, falsifiable hypothesis?
a) The disease COVID-19 is caused by the coronavirus SARS-CoV-2
b) Transmission of the SARS-CoV-2 virus occurs primarily through respiratory droplets
c) The COVID-19 pandemic is punishment for human destruction of the environment
d) The SARS-CoV-2 virus emerged from a single transmission from animals to humans, rather than many transmission events
The COVID-19 pandemic is punishment for human destruction of the environment
We cannot test the “idea” that the pandemic is punishment of any sort; can’t collect data that can falsify this idea
Early ideas about Evolution can be tracked to 3 philosophers
Anaximander (611-547 BC), Empedocles (492-432 BC) and Lucretius (99-55 BC) proposed that all living things were related and that they had changed over time
Who demonstrated that things change over time?
Aristotle in his Scala Naturae explained the advancement of living things from inanimate matter to plants, then animals and finally man
It was thousands of years before these ideas were widely accepted
Early ideas about Evolution
Zhuangzi (circa 300 BC) proposed that life forms have an innate ability to transform and adapt to their surroundings
he also indicated that humans are subject to this process
Al-Jahiz (781-869)
Arab scholar interested in natural history proposed the first modern theory of evolution in the Book of Animals
Largely ignored by the western world, but possibly inspired Darwin
Al-Jahiz’s Theory of Evolution
Animals engage in a struggle for existence, for resources, to avoid being eaten and to breed
-Many of these ideas are similar to MARKIAN evolution
Environmental factors influence organisms to develop new characteristics to ensure survival, thus transforming into new species
Animals that survive to breed can pass on their successful characteristics to offspring
Early ideas about evolution: Avicenna
980-1037
Persian scholar and philosopher
One of the most important scientists in history - discovered the nature of infection diseases
Proposed for the first time the Law of Superposition: Older layers of sediment are covered by younger layers
Law of Superposition
Older layers of sediment are covered by younger layers
Helps us determine AGE of earth
Can age sediment based on how deep they are
Setting the stage for evolutionary theory: gradual change over time
Early thinkers assumed the earth was young
Leonardo da Vinci (1452 - 1519) calculated the sedimentation rates in the Po River of Italy, and concluded it took 200,000 years to form some nearby rock deposits
-Using superposition to age it, lower layers will be older than layers higher up in rock
Setting the stage for evolutionary theory: Uniformitarianism (gradual change over time)
First proposed by George-Louis Leclerc, James Hutton and refined by Charles Lyell in the 1800’s
Basis of Uniformitarianism
Idea that slow acting processes over long periods of time can produce dramatic results
Contrasted with prevailing view of “catastrophism”
Catastrphism
Geological features emerge from major, catastrophic events
i.e. the Grand Canyon formed by SLOW PROCESSES, not catastrophe
Uniformitarianism
Important because accepting gradual change means that these changes are observable and could be tested experimentally
Difficult to observe, measure, and manipulate changes that occur due to unpredictable natural catastrophes
Setting the stage for evolutionary theory: The struggle for existence
Erasmus Darwin (1731-1802), grandfather of Charles Darwin, discussed the notion of a STRUGGLE FOR EXISTENCE:
- Organisms are in a constant struggle to obtain resources and use those resources to produce offspring
- Humans descended form another primate
- Failed to connect struggle for existence to evolutionary change over time
Even though he observed competition, he did NOT see the struggle for existence as a driver for evolution (couldn’t prove this hypothesis)
Setting the stage for evolutionary theory: Species change through time
Robert Chambers (1802-1871) in his Vestiges of the Natural History of Creation highlighted two critical points about the fossil record:
- The species composition changed through time
- -You don’t find identical species in different layers; in history, there has been some change in the species present on earth
- This change is slow, gradual and unlinked to catastrophes
- -Support for Uniformitarianism
Hypothesized new species arise from old species
Did not explain WHY new species arise (answered by Charles Darwin)
Setting the stage for evolutionary theory: Organisms are well-suited to their environments
William Paley (1743-1805) in his Natural Theology discussed the metaphor of the Watchmaker
Organisms are like watches, if one piece is absent of misplaced the watch will fail to function
Recognized that organisms were well-suited to their environments
He assumed a supernatural creator must have put them together; NOT a testable hypothesis
Setting the stage for evolutionary theory: Adaptation
Jean-Baptiste Lamarck (1744-1829) in his Zoological Philosophy proposed this Theory of Adaptation
More complex species descend gradually from older, less complex species
This occurs through a process of adaptation, in which organisms acquire new traits during their lifetimes
Formation of complex from more simple due to adaptation
Lamarck: Inheritance of acquired characteristics
Hypothesized that an organism can acquire characteristics during its lifetime and pass them on to its offspring
-The long legs of shorebirds are the results of birds stretching their legs to avoid sinking in the mud
Connected PHENOTYPE ot environment
Idea: giraffes got long necks to reach leaves on tops of trees, passed on to offspring
This is INCORRECT, but this is the first time that a phenotype was connected to the environment
Phenotype - Lamarck
Key Vocabulary: Phenotype
The outward appearance of an organism
Setting the stage for evolutionary theory: More individuals are produced than can survive
Robert Malthus (1766-1834) argued that humans would outstrip the available resources necessary to sustain themselves, leading to population growth that would be checked by famine, war, and disease
Malthus came up with the idea that more individuals are produced than can survive Malthus was not a scientist
Applies to natural populations: Food supply is constant and population growth tends to be exponential
When resources are limited, the best suited organisms obtain more resources than the rest
Which is NOT a key component of early evolutionary thinking?
a) Survival of the fittest
b) Change in genotypes over time
c) The progression from simple to more complex and sophisticated forms over time
d) One species turning in to a different species
b) Change in genotypes over time
Genotypes were not yet discovered
Major developments that PRECEDED Darwin
1) Shift from supernatural explanations to methodological naturalism in explaining the natural world
2) Shift from logic and reason to observation, testing, refutation
- Falsifiable hypotheses rather than spirituality
3) View world as in state of flux or change, rather than unchanging
- See world as old
4) Shift from catastrophism to uniformitarianism (gradual change over long periods of time)
5) Away from ideas of spontaneous generation and stasis to recognition that species come from other, related species
6) Organisms are suited to their environments and compete for resources
Charles Darwin
Formulated Evolutionary Theory as we understand it today
From a wealthy family in England
Was in training to become a medical doctor, but found it boring
Preferred natural history and spent time collecting beetles and studying geology
The voyage of the HMS Beagle
Darwin obtained a position as the ship’s naturalist on the HMS Beagle’s second voyages around the world form 1831-1836
He was 22 years old
Made extraordinary collections of plants, animals, and fossils
Shipped specimens back to England, recorded in journals
Darwin after the Beagle
After the journey on the Beagle, Darwin began sifting through his journals and wrote a popular book, The Voyage of the Beagle
Struck by mockingbirds and tortoises in the Galapagos
Found support of Lyell’s ideas about uniformitarianism (gradual change over time) in his fossils
Published voluminously on orchids, coral reefs, barnacles, pigeons, corresponded widely with other scientists
Darwin worked on his ideas about natural selection for nearly 23 years
-Worked in secret at first
Was tormented by his ideas and afraid of their implications
-Knew ideas would be controversial that humans would be subject to same process (i.e. too unique)
Amassed extensive evidence for his ideas via experimentation and artificial selection
What caused Darwin to publish? Alfred Russel Wallace
Alfred Russel Wallace
1823-1913
Came from working-class family
Spent many years in S American and Southeast Asia and published salvaged notes from his discoveries (lost notes in shipwrecks)
In 1854, went to study the natural history of Indonesia, where he contracted malaria
During fever, he wrote down his ideas on natural selection
Darwin, Wallace, and Natural Selection
Darwin and Wallace independently discovered the role of natural selection in the formation of species
In 1858 Darwin received a letter from Wallace, in which Darwin’s unpublished theory of natural selection was described
-Darwin was a highly respected scientist in that time
Darwin and his colleagues arranged for Wallace’s papaer to be read at the July 1, 1858 meeting of the Linnaean Society, along with a letter on the same subject by Darwin
-Co-presented Darwin’s and Wallace’s work
Darwin published __________ in 1859
The Origin of Species
His seminal work
Darwin laid out entire theory of Natural Selection in _______-
ONE PARAGRAPH
The rest of his book amassed evidence to support ideas
Theory of Natural Selection
More species are born than can survive = struggle for existence
Greater chance of survival for those that fit environment
Darwin’s First Key Insight: Evolution by natural selection - 4 key Observations
1) Phenotypes vary within a population - variation in size, height, color, weight, etc.
2) More offspring are produced in a generation than can survive - Comes back to Malthus’ idea that is a population outstrips its food supply, not all can survive
3) Phenotypes are heritable (to some extent) - Strong principle of inheritance; if you have tall parents, you’re more likely to be tall
4) Some phenotypes will have better survival and become more prevalent in the population over time - Some phenotypes more likely to survive and reproduce more; favorable characteristics will become more prevalent over time
Components of Natural Selection: Variation
Members of populations vary in the traits they display
Components of Natural Selection: Inheritance
Offspring tend to resemble their parents
Components of Natural Selection: Differential reproductive success
Brighter beetles are bitter and predators learn to avoid them. Bright beetles are more likely to survive and reproduce than duller-colored beetles
Result = Evolution by natural selection. Proportions of different variants in beetle population change over time
Malthus’s ideas applied to nature
Difference between individuals produced in a generation and resources available is the potential for natural selection to act
The difference reflects the zone in which natural selection by resource limitation occurs and in which less-fit forms are unable to survive
Darwin’s first key insight
“Nature” selects on variation in traits of individual organisms, because some variants are better suited to survival than others
Natural selection is then the differential survival of individuals who are best suited to their environment
Over time there will be enough heritable changes, resulting in a transformation of the original species into a new species similar to, but distinct from, its parent species
Process also referred to as “descent with modification”
Descent with modification
Over time there will be enough heritable changes, resulting in a transformation of the original species into a new species similar to, but distinct from, its parent species
What is Evolution?
a) Survival of the fittest
b) Change in genotypes and phenotypes over time
c) The progression from simple to more complex and sophisticated forms over time
d) One species turning in to a different species
b) Change in genotypes and phenotypes over time
This is the more supported definition now
Darwin’s second key insight: Common ancestry
Common ancestry of all living things: Species resemble each other because they are descended from common ancestors
Noted by scholars LONG before Darwin that species resemble each other
Darwin theorized that all species descended from one common ancestor
Common ancestry explains ___________
Clustering patterns in nature
Similar species cluster together hierarchically
All squirrels are more closely related to each other than any is to an antelope
A process of branches subdividing would naturally give rise to these hierarchies
What is a species?
Dog breeds are VARIETIES of a species
Varieties vs. Species
Selection on varieties was well accepted, but the jump to “new species” was a challenge for many critics - Breeder selects for certain varieties
To Darwin, the distinction between a “variety” and a “species” was arbitrary - A variety is an earlier form on the path to a species according to Darwin
If varieties are similar to species, we can recognize the concept of descent with modification
Darwin argued that the process of artificial vs. natural selection were essentially the same, with only the traits and the selective agents (humans vs. nature) different
-Humans may select for high milk production, nature may select for camo colors
Central components of evolutionary theory
Species are not immutable - they may change through time
Species are not derived independently - they share common ancestors
Species change slowly - the earth is very old
Species are well-suited to their environments - this is caused by natural selection
Consequences of evolutionary theory
Natural (as opposed to supernatural) explanation for origins and diversity of life on earth
Framework for studying and understanding commonalities and differences among all living things
Lamarckian Evolution
Transformational process
i.e. Giraffe with short neck gets long neck IN ITS LIFETIME and passes on to offspring
Thought that organisms were well-suited to environment because they acquired traits in their lifetime (i.e. giraffes stretched up to reach leaves on trees = longer necks and passed on to offspring)
Individuals change WITHIN their lifetime to better suit environment
Darwinian Evoluion
Variational process
CORRECT process of evolution
Individuals do NOT change within lifetime, the ones that are suited to environment are those that survive
In Lamarck’s theory of evolution, species evolve:
Independently and in parallel
Linear progression
In Darwin’s theory of evolution, species are:
Descended one from another to form a branching tree of life
Branching tree of life
Lamarck
Variation is made to fit what an organisms wants or needs
(If an organism NEEDED to have a certain trait, Lamarck believed that it would get that trait in its lifetime)
Darwin
Variation exists naturally in populations
(Variation occurs naturally, organisms do NOT obtain characteristics they do not have int heir lifetime just because it is best suited to environment
Lamarck
Individuals ACQUIRE characteristics in their lifetimes and transmit these characteristics to their offspring
(Individuals must acquire a characteristic to suit environment and pass on to offspring)
Darwin
Individuals that have characteristics beneficial in a particular environment pass those characters to their offspring
(Individuals already possessed a character and pass that character on to offspring)
Lamarck
Organisms follow a directional, linear path of increasing complexity over time
Suggests a plan to evolution
Darwin
There is no “plan” - evolution is an undirected process
Individuals respond to prevailing environmental conditions
Lamarck
No extinction
Darwin
Extinction
Extinction IMPORTANT in evolution
Which one of these assertions is Darwinian and not Lamarckian?
a) An individual that acquired new characteristics in its lifetime is able to transmit them to its offspring
b) INdividual organisms evolve because they need to survive or use new resources
c) There is no extinction
d) Individuals better suited to their environment reproduce more than others and pass beneficial characteristics to their offspring
d) Individuals better suited to their environment reproduce more than others and pass beneficial characteristics to their offspring
Broad classes of evidence supporting evolution
Artificial selection
Island radiations
The fossil record
Behavioral data
Morphological data
Embryological data
Molecular data
Building the Evidence: Artificial Selecion
Darwin relied on ARTIFICIAL SELECTION to build evidence for natural selection
-Relied heavily on artificial selection to build evidence for natural selection; same process, different driver
By breeding certain varieties of an organism over others, humans can rapidly change the appearance and even the behavior of an organism
Pigeon breeding lead to a wide range in color variations, flying habits, behavior, and so on
Darwin argues that pigeon races would be considered different species or even genera if we did not know how they were produced
Building the Evidence: Island Radiations
Observation of island organisms lead both Darwin and Wallace to breakthrough discoveries
Darwin influenced by Galapagos Islands; Wallace influenced by islands off Southeast Asia
After examining Darwin’s collections, ornithologist John Gould confirmed that what Darwin thought were many unrelated species were all finches and what he thought were varieties of mockingbirds were different species
On islands, radiation of species that occupy different niches
Mockingbirds look somewhat similar; proven to be different species
Radiations on islands
Organisms fill available ecological space (‘niches”)
Radiations of many phenotypes and morphologies
Bushbaby - first primate to find its way to Madagascar; radiated into many different forms due to lack of predators
Adaptive Radiations
Rapid diversification into many forms from a common ancestor
Ecological analogues
Unrelated organisms display similar adaptations to the same ecological niches - kangaroos and cows both have 2 stomach chambers for fermenting grasses and other plants
Support for natural selection: Repetition of similar traits in similar environments in different animal species
Building the evidence: Fossils
A fossil is any mineralized evidence of a once-living organism
This includes body parts, casts, molds, footprints, track ways, and feeding traces
The vast majority of fossils are found in sedimentary rocks
Fossilization
Most organisms will NOT end up being preserved after death
The fossil record represents only a tiny fraction of all the individual organisms that inhabited the Earth
Process of fossilization is very specific; need to have right type of soil, water, all of these steps
Process of Fossilization
Animal dies on lakeshore
After soft tissue decays, only skeleton left
Water level rises, sediment covers bones
Bones fossilize in thick layer of sediment at bottom of lake, while sediments continue to be deposited as layers
Lake dries and other geologic processes occur. Volcanic eruption spews ash over region, providing more layers. Fossil now embedded in geologic stratum
Erosion exposes deep strata in a geologic column, revealing the fossilized skeleton
Superposition
Older layers of sediment are covered by younger layers, so that in a sedimentary sequence the youngest layer is at the top
Succession
Different layers contain particular types of fossilized organisms
These fossils replace each other in a specific and predictable temporal order that can be identified and dated
-We can see when new forms arise based on the layer their fossils are in
Transitional forms
Formerly called “missing links” they represent organisms with intermediate characteristics between other major groups
-Important in determining relationships between organisms
There are thousands of examples of intermediate forms linking virtually all groups of organisms
Fossil records thus capture gradual changes in organisms over time
Transitional Examples
Archeopteryx: Dinosaur with feathers, dino turning into a bird
Tiktaalik transition from water to land
The methods used to find fossils to fill in gaps is actually very rigorous
Limbed animals thought to come from fish; the black was the initial hypothesis; Tiktaalik was the missing link
Transitional example: Tiktaalik
Finding transitional fossils is not necessarily random
To find Tiktaalik, scientists used existing fossils to determine when in the past limbs SHOULD HAVE evolved
They then searched for where on earth the right kind of rock existed from that time period
When they dug in that location, they found the fossil they were looking for
What is the basic idea behind natural selection?
a) Differential survival when resources are limited
b) Extinction when resources are limited
c) Inheritance of acquired traits
d) Sexual reproduction
a) Differential survival when resources are limited
Darwin’s Challenges:
Evolution of complex traits: Structures with multiple intricate parts, like eyes
-Hard for him to explain how complex structures could evolve via a slow process
Traits and structures of seemingly little importance - nipples on male animals
Elaborate traits that offer no fitness advantage
The source of variation
-Knew that populations vary and knew that the variation is heritable, but he did not know WHY
We now have answers to all of these problems, as we will see in later lectures
Darwinian Genetics
The mode of inheritance was also a huge problem for Darwin - he knew traits were transmitted from parents to offspring, but he didn’t know how
Darwin speculated that characteristics of the parents were blended - like mixing paint - as they passed to the offspring
-Got this WRONG
But if that was true, how could a single fortunate change be spread through a species?
After Darwin’s death, alternative evolutionary mechanisms were proposed, none of which were ultimately supported
-The discovery of DNA is what helped in understanding the variation within species
What is Evolution?
Evolution is change over time, the change in allele frequencies (genetic variants) over time
Darwin did NOT initially describe evolution as changes in allele frequencies. He conceptualized it as changes in phenotype - the outward appearance of an organism
-We now know that phenotypes are determined by underlying alleles
Critical reception of the Origin
Book sold out immediately and was widely debated
Ideas were (surprisingly to Darwin) generally widely accepted among scientists
Detractors claimed ideas were too dangerous for “ordinary” readers
Anglican church was divided, but natural selection was viewed as a conception of a deity by many
Evolution in the US: The Scopes Trial (1925)
Teaching human evolution was banned in Tennessee
Trial pitted Christian Modernists against Fundamentalists
Scopes ultimately found guilty, but public opinion is generally thought to have turned against Fundamentalists
In 1968, the Supreme Court ruled that bans on teaching evolution in public schools violate the Establishment Clause of the First Amendment by promoting a specific religion
Challenges to Evolution: Intelligent Design
Michale behe and collaborators at the Discovery Institute proposed the idea that some structures are too complex at the biochemical elvel to be adequately explained as the result of evolution
A creator therefore must have been involved in the production of such structures
This group pushed to have Intelligent Design taught in biology classrooms
Promotes the idea that there is some deity behind natural selection; not a testable and falsifiable hypothesis
Dover School District Trial
Whether Intelligent Design could be taught in High School classrooms
In Kitzmiller vs. Dover Area School District Trial, Judge John E. Jones III said:
“The overwhelming evidence at trial established that Intelligent Design is a religious view, a mere re-labeling of creationism, and not a scientific theory.”
Evolution today
No serious legal challenges to teaching evolution in public schools since Kitzmiller v Dover
Large percentages of Americans report feeling “unsure” about their belief in evolution
Rejection of science and fact- and evidence-based decision making at all levels of society
Which of these are central components of evolutionary theory?
a) Species change over time
b) Species share common ancestors
c) Species are well-suited to their environments
d) All of the above
d) All of the above
What were Darwin’s two key insights about evolution in the Origin?
1) Evolution by natural selection
2) Common ancestry
What are the four components of natural selection we discussed in class?
1) Phenotypes vary in population
2) More offspring produced than can survive
3) Phenotypes are heritable
4) Some phenotypes are more likely to survive
What is artificial selection?
Humans breed certain varieties for specific traits; very similar to natural selection, just different method of obtaining results
Is natural selection variational or transformational? Why?
Variational
Variational is the method proposed by Darwin: Occurs via extinction, slowly over time, only those that suit environment will survive
Which of these is NOT a testable hypothesis?
a) Species are designed to be suited to their environments by a “watchmaker”
b) Most geologic change on earth is caused by catastrophic events
c) Species do not change over long periods of tie
d) Species are able to acquire novel adaptations during their lifetimes
a) Species are designed to be suited to their environments by a “watchmaker”
Which is correct about Darwin’s views on natural and artificial selection?
a) He viewed them as fundamentally different processes
b) He viewed them as essentially the same process, with only the selective agent differing
c) He believed only artificial selection could produce new species
d) He thought natural and artificial selection could produce new varieties, but not new species
b) He viewed them as essentially the same process, with only the selective agent differing
Under Darwin’s hypothesis of a common ancestry of all living things, we would expect to observe:
a) Hierarchical clustering and a branching tree of life among all living things, wherein species that appear to be more similar are more likely to be closely related
b) Species independently progressing from simple to more complex over time
c) Random and unpredictable relationships among species
d) Hierarchical clustering among varieties, but no predictable clustering among species
a) Hierarchical clustering and a branching tree of life among all living things, wherein species that appear to be more similar are more likely to be closely related
Methodological naturalism set the stage for the modern scientific method by:
a) Stating that the earth changed gradually over time
b) Demonstrating that species are adapted to their environments
c) Seeking explanations for the natural world driven by physical laws
d) Suggesting that animals struggle for existence
c) Seeking explanations for the natural world driven by physical laws
Which of these is NOT a component of natural selection as described by Darwin?
a) Organisms reproduce via sexual reproduction
b) Survival and reproduction are non random: individuals carrying specific variations survive and reproduce the most
c) Individuals within species are variable
d) Individuals pass their variants on to their offspring
a) Organisms reproduce via sexual reproduction
Which of these was a challenge for Darwin to explain under his theory of evolution?
a) All of these were challenges for Darwin to explain
b) Structures of seemingly no importance
c) Complex structures such as eyes
d) Elaborate traits with no fitness advantage
a) All of these were challenges for Darwin to explain
A consequence of Malthus’s ideas that populations outstrip their available resources is that:
a) Individuals will acquire heritable characteristics that help their offspring survive
b) The individuals best able to monopolize resources will survive
c) Individuals vary within a population
d) Individuals resemble their parents
b) The individuals best able to monopolize resources will survive
What is the definition of evolution?
a) Acquisition of beneficial characteristics
b) Change in allele frequencies over time
c) Resemblance of offspring and parents
d) Survival of the fittest
b) Change in allele frequencies over time
Transitional forms are:
a) Species with intermediate characteristics between major groups
b) Species exceptionally adapted to their environments
c) Ecological analogues to other species
d) Groups that radiated on islands
a) Species with intermediate characteristics between major groups
Which of these assertions is Darwinian and not Lamarckian?
a) An individual that acquired new characteristics in its lifetime is able to transmit them to its offspring
b) There is no extinction
c) Individuals better suited to their environment reproduce more than others and pass beneficial characteristics to their offspring
d) Individual organisms evolve because they need to survive or use new resources
c) Individuals better suited to their environment reproduce more than others and pass beneficial characteristics to their offspring
