Evidence, Origins and History

Question 1

Define descent with modification.

Answer 1

The concept that all organisms present or past are descended from a single common ancestor, and that over time lineages genetically and phenotypically changed and split to form many branches

Question 2

Define phylogeny.

Answer 2

A representation of the history of descent, and thus evolutionary relationships and common ancestry.

Question 3

Define paleontology.

Answer 3

The study of ancient organisms preserved in the fossil record.

Question 4

Define fossil record.

Answer 4

Collection of all known fossils.

Question 5

Define homology.

Answer 5

The same organ inherited from a common ancestor which develops into a variety of forms and functions

Question 6

Define uniformitarianism.

Answer 6

The processes that shape the earth now are the same ones that shaped the earth in the past.

Question 7

Define inheritance of acquired characteristics.

Answer 7

Progeny inherit traits acquired by parents.

Question 8

What are the two types of evidence used to support evolution?

Answer 8

Pattern-based/indirect evidence
Direct evidence

Question 9

What is the metaphor used to describe indirect evidence of evolution?

Answer 9

The fingerprints of evolution.

Question 10

What are the three types of pattern-based evidence?

Answer 10

Paleontology
Developmental biology
Homology

Question 11

What are the two types of homology used as evidence of evolution?

Answer 11

Morphology and genetic

Question 12

Give examples of direct evidence of evolution.

Answer 12

o E. coli
o Influenza, COVID
o Darwin’s finches

Question 13

What 3 conclusions are supported by paleontological data regarding the evolution of birds?

Answer 13

o The original organisms we saw in the early fossil record are now extinct
o Ancient feathered dinosaurs evolved through time and gave rise to modern birds
o Birds are the living descendants of dinosaurs

Question 14

What are the 2 strengths of paleontology discussed in class?

Answer 14

o Provides snapshots through time
o Allows us to infer evolutionary changes and diversification

Question 15

What are the three weaknesses of paleontology discussed in class?

Answer 15

o The fossil record is not continuous (large gaps)
o Soft tissues rarely preserved
o Captures a fraction of the diversity

Question 16

In terms of developmental ontology, what is typically the case for organisms that are more closely related?

Answer 16

• It is usually the case that organisms that are more closely related share similar developmental ontology (i.e., steps of embryological development)

Question 17

What is the importance of similarities in the developmental ontology of different organisms?

Answer 17

Provide evidence for modification by descent and help us understand homology

Question 18

How is embryological development similar for snake, chicken, possum, cat, bat and human embryos?

Answer 18

All have fat heads, pharyngeal pouches and tails in early stages

Question 19

Give examples of genetic homology

Answer 19

All life uses nucleic acids to store information, direct cellular processes and direct replication
All genes are contained within chromosomes

Question 20

What is the best evidence for all life sharing a common ancestor?

Answer 20

Shared genetic code (DNA, RNA)

Question 21

Describe the endosymbiosis theory for the evolution of early life.

Answer 21

o Bacterium engulfed a smaller bacterium
o Was not digested
o Had its own functions
o Became single organism  eukaryotic cell
o Eukaryotic cell engulfed photosynthetic bacterium  plastids

Question 22

What is the most recent common ancestor of all extant organisms known as?

Answer 22

LUCA: o Last universal common ancestor

Question 23

What is the RNA world hypothesis?

Answer 23

generally believed that first life had to satisfy the following conditions:
o Information containing biomolecules made from simple inorganic compounds
o Building blocks must be able to self-assemble and replicate
o Chemical reactions to form larger molecules must increase fitness (replication) and have a source of energy
o Larger biomolecules must be protected from harsh environments

Question 24

What is the theory of special creation?

Answer 24

Literal interpretation of the Bible’s Book of Genesis

Question 25

What is the pattern of life according to the theory of special creation? (3)

Answer 25

o Species don’t change through time o Species were created independently of one another o Species were created recently

Question 26

What is the mechanism of life according to the theory of special creation?

Answer 26

o The Earth and its species were created by separate and independent acts of a designer (God)

Question 27

What is meant by inheritance of acquired characteristics?

Answer 27

species gradually evolve through time, from simple forms to more complex by passing on adaptive traits acquired throughout their lifetime to their offspring.

Question 28

Who proposed the evolutionary mechanism of inheritance of acquired characteristics?

Answer 28

Lamarck

Question 29

What were the 4 topics that affected Darwin's thinking?

Answer 29

Natural history Uniformitarianism Artificial breeding Exponential population growth

Question 30

What components of natural history were of particular interest to Darwin?

Answer 30

o Fossils o Extinction o Species differences o Variation within species

Question 31

How did uniformitarianism impact Darwin's thinking?

Answer 31

thought Lyell’s ideas on geology might also apply to species o Earth is old o Species are modified today in the same ways they were modified in the past

Question 32

How did artificial breeding influence Darwin's thinking?

Answer 32

o Noted that artificial breeding could quickly change lineages by selecting certain traits o This could occur only if offspring inherited traits from their parents

Question 33

How did exponential population growth influence Darwin's thinking?

Answer 33

o Virtually all populations produce more young than can survive o If an individual varied in such a way that increased its survival, or allowed it to have more offspring, it would pass on its traits to its offspring

Question 34

What is the criteria for evolution by natural selection? (3)

Answer 34

* Individuals within populations vary in phenotypic traits * At least some of the variation in traits has a genetic bases and is thus heritable * Variation in these traits influences reproductive success (fitness), in terms of survival and/or the production of offspring

Question 35

Identify 4 major criticisms of Darwin's theory of evolution

Answer 35

1. Religious: contradicted scripture Scientific: 2. Lacked an empirically valid explanation for inheritance 3. Stressed the importance of continuous variance 4. Disagreed on natural selection as the mechanism

Question 36

What is the law of segregation?

Answer 36

If a parent is heterozygous at a given locus, it will produce male and female gametes that contain one of the other allele, in equal proportions.

Question 37

What is the law of independent assortment?

Answer 37

Alleles at one locus segregate separately from alleles at a separate locus.

Question 38

Describe post-Darwinian thought, I.e., mutation theory of evolution (4)

Answer 38

1. Genes are the hereditary unit, where alleles at a locus encode for discrete variation in traits. 2. Selection acts on Mendelian (discontinuous) traits. 3. Selection cannot cause a population to evolve beyond the initial variation in the population without new mutation 4. Therefore, mutation must be the dominant mechanism of evolution, selection is of less importance (Mutation theory of evolution)

Question 39

What was the timeline of the modern synthesis?

Answer 39

1918-1970

Question 40

Who were the three founders of the modern synthesis?

Answer 40

o Ronald A. Fisher o Sewell Wright o J.B.S. Haldane

Question 41

What are the 10 fundamental principals of evolutionary biology?

Answer 41

1. Genes store the information underlying heritable characters 2. Phenotype = genes + environment 3. Acquired characters are not genetically inherited 4. Mutation is the origin for all heritable variation 5. Evolution is a population process 6. Evolutionary potential of a population is a direct function of the amount of genetic variation in fitness 7. Changes in allele/genotype frequency occur as a result of five mechanisms a. Mutation b. Selection c. Genetic drift d. Dispersal e. Non-random mating 8. Species are groups of interbreeding individuals 9. Speciation is the origin of two or more species from a single common ancestor 10. All organisms form a great tree of life descended from a common ancestor

Question 42

Describe the process of calculating a rock's absolute age through radiometric dating/

Answer 42

o 1. Determine half-life o 2. Parent:daughter isotope ratio determined, typically via mass spectrometry o 3. Multiply number of half-lives passed by length of half-life to determine age

Question 43

What is the key assumption of radiometric dating?

Answer 43

The ratio of parent-to-daughter isotopes present when the rock was formed is known