T2 - Darwin + theory of evolution

Question 1

What is Scala Naturae?

Answer 1

Aristotle recognized certain similarties among organisms and arranges life into a linear sequence of increasing complexity

The great chain of being, not just including humans (gods/supernatural/angels)

Question 2

What is the watchmaker analogy?

Answer 2

An ‘argument from design’ arguing that the complex structures of living things and the remarkale adaptations of plants and animals are evidence of an intelligent designer

Ex. a pocketwatch is intricately complex and only performs one function, yet if you change one thing, it will no longer function as needed

Question 3

What is a taxonomic system? Who developped this?

Answer 3

Carl Linnaeus developped the taxonomic system in which all organisms are arranged in hierarchical groupings based on similarities

With lower groups nested with higher ones

Question 4

Who introduced the idea that the Earth was young? How was this disproved?

Answer 4

Christianity introduced the idea that the Earth was young

It was later found that sediementary rocks had been laid down under ancient oceans, Hutton argued that the way the rock strata were aligned and how the process of erosion and sedimentation worked indicated that the world must be inconceivably old

Lyell explained that the geological processes we currently observe must have operated over very long periods of time in a slow, gradual manner

Question 5

What is uniformitarianism vs catastrophism?

Answer 5

Uniformitarianism = Uniform processes happening over fast periods of time, given sufficient time (rock erosion can explain the formation of the grand canyon)

Catastrophism = Due to large catastrophes (God created a flood which is why some of the Earth is shaped in certain places)

Question 6

What disproves the fixed view of the world that the species were all created by a higher being?

Answer 6

Extinction = there exists species in the fossil records that were not living today

Extinction challenges the idea that the Earth flora and fauna have been constant (allowing for change and long periods of time in which it can occur)

Question 7

What was Lamark’s theory of evolution?

Answer 7

Provided the first detailed theory of evolution, proposing that new more complex species descended gradually from older, less complex ones

Also (incorrectly) suggested that this occurs via the inheritance of acquired characters - traits acquired during the lifetime of an individual (traits passed on)

Question 8

What is the importance of the Galapagos islands? What did they contribute to the theory of evolution?

Answer 8

It was observed that the fauna on each island were similar but distinct and resembled different species

The most prominent example; many distinct forms of finches were found only in the Galapagos with different beaks for different functions as each had adapted or evolved to better fit their unique habitats

Contributed in the manner that this disporves that a creator made specific species for each habitat

• Otherwise if a certain phenotype is for a specific habitat, then there would not be variation within one type of phenotype

Question 9

What was Darwins ‘one long argument’?

Answer 9

1. Descent with modification

• All species have descended with modification from one or a few common ancestors
• Species do not arise from independent acts of creation but they evolve from pre-existing species

2. Natural selection

• NS is the mechanism unerlying much of this evolution, explaining how the characteristics of organisms change over time and explaining the remarkable fit between organisms and their environment

Question 10

What is the definition of evolution?

Answer 10

A change in a heritable character in a population over time

• A change in allele frequency in a popuation over time (change in the DNA in order for a species to evolve and adapt over time to different conditions
• Note; populations evolve, individuals do not

Question 11

What is homology?

Answer 11

Originally referred to curious similarities in structure despite differences in function

Similarity e to inheritance from a common ancestor

Question 12

What serves as evidence of a common descent?

Answer 12

a) homology
b) vestigial structures
c) fossils
d) biogeography

Question 13

What is biogeography? How does it serve as evidence of a common descent?

Answer 13

Living species tend to be similar to others geographically nearby and to fossil species in the same area

Species that resemble each other tend to be clustered in time and space

Question 14

What is resource limitation?

Answer 14

We create more offspring than we have the capabilities to nurture - not enough resources

• This initiates competition; individuals who contain better suited traits create more offspring
• These traits become more common and increase in populations having a higher success of being passed on

Question 15

Why might extincting occur in reference to NS?

Answer 15

Any trait that enables individuals to have better survival and reproduction rates will cause those bearers to leave more offspring than others lacking the trait

• When one is no longer fit for survival, its genes will not be passed on at a high rate and eventually it will go extinct

Question 16

What are 3 critical observations that are needed for NS to occur?

Answer 16

1) There is excess fertility such that more offspring are produced than the environment can support

• Fierce struggle for existence (for resources) among members such that only a portion of offspring survive to reproduce

2) Individuals vary; no 2 are exactly the sa,e

• success in the struggle for existence is not random but depends on the traits facilitating it (process of NS)

3) Much of the variation is heritable

• traits that increase success will become more common (evolution by NS)

Question 17

Why is NS considered deductive reasoning?

Answer 17

If certain conditions are met, then this outcome must occur

If;
1) Individuals vary in a trait
2) There is a non-random association between the trait and an individuals reproductive success (Darwinian fitness)
3) The trait is heritable

Then; the trait will evolve

Question 18

What is fitness in regards to evolutionary biology?

Answer 18

A measure of the capability of an individual (genotype) to contribute to the next generation (reproductive success)

• How many offspring are produces?
• Do the offspring survive to the reproductive age?
• Is the reproduction successful?

Question 19

What is artificial selection?

Answer 19

Breeding those with desired characters

Manipulating a population rather than allwoing natural selection to occur (interfering with an IV rather than sitting back)

• This method produces varieties and these varieties can ultimately become new species as differences accumulate

Question 20

How do artificial and natural selection differ?

Answer 20

• AS has a goal and a foresight
• AS fitness is imposed upon while in NS it is not
• Both AS and NS require phenotypical variation
• Both AS and NS requires the trait to be heritable

Question 21

Why might AS be more widely accepted than NS?

Answer 21

NS will exhaust variation, haltingany further evolution

• NS will consume varitiaon eventually leading to none at all

Question 22

What is experimental evolution?

Answer 22

A technique in which biotic and/or abiotic conditis are manipulated in replicate populations under controlled conditions as the evolutionary outcome is studied

Question 23

What is Mullerian mimicry using the example in Heliconus?

Answer 23

Selection would favoushared warning signals in 2 distasteful butterfly species because it spreads the selective burder of educating predators

Changes within the species changes due to its surrounding environment/species

Question 24

List some misconceptions about evolution.

Answer 24

1. NS is not goal driven nor progressive

• although it has increased complexity and specialization in some lineages over time, in others it has not = this is not a goal of evolution
• it is simply a process that occurs when certain conditions are met
• it makes organisms better only in the sense of improving their fit to their current environment
• adaptation with no goal in mind

2. NS does not act for the ‘good of the species’

• selection arises from variation in relative, not absolute fitness
• NS can and often does favour traits that are detrimental to a population/species (if a male trait endangers the life of the female)

3. NS does not result in perfection

• physical environments can change such that traits that were previously adaptive may no longer be (environmental change may be sufficiently rapid that there is evolutionary lag)
• Biotic environments evolve and often coevolve = in some cases actively thwarts adaptation (race between predators and prey)
• selection is a function of the current environment only (lacks foresight)
• sorts among existing variations
• trade offs exist such that all cannot be individually perfect

Question 25

What are evolutionary conflicts of interest?

Answer 25

When traits that maximize fitness in one individual are costly to the other

Question 26

What is creationism?

Answer 26

Belief that nature and the universe originated from supernatural acts of divine creation

Used as a hypothesis for explaining the diversity of life on earth, adaptation, biogeography, fossil record…

• however neither are scientific because they cannot be refuted