Descent with Modification: A Darwinian View of Life

Question 1

Briefly describe the concept of artificial selection.

Answer 1

Artificial selection is the process by which humans breed organisms with desired traits, leading to the accumulation of those traits over generations.

Question 2

Charles Darwin’s observations during his voyage on the Beagle included:
a) The diversity of life on different continents
b) The existence of identical life forms across all geographical locations
c) Evidence that Earth was only a few thousand years old
d) None of the above

Answer 2

a) The diversity of life on different continents

Question 3

Darwin noted that all living things have the potential to produce more offspring than the environment can support, leading to a _____ for existence among individuals.

Answer 3

struggle

Question 4

TF: Darwin observed that traits are passed from parents to offspring, but he did not understand the mechanism of inheritance (later explained by Mendel’s work on genetics).

Answer 4

True

Question 5

How did observations of variations within populations inform Darwin’s ideas about natural selection?

Answer 5

The presence of variations in traits within a population provided the raw material for natural selection to act upon. Individuals with traits better suited to their environment would have a higher chance of survival and reproduction, leading to the gradual change of the population over generations.

Question 6

What are the two main inferences Darwin drew based on his observations?

Answer 6

1. Individuals with heritable traits that better enable them to survive and reproduce in a given environment will tend to leave more offspring than other individuals (survival of the fittest).
2. This unequal ability of individuals to survive and reproduce will lead to the gradual accumulation of favorable traits in a population over generations.

Question 7

The theory of descent with modification proposes that:
a) Species are unchanging and divinely created
b) Life arose independently on multiple occasions
c) All living things share a common ancestor and have undergone evolutionary change over time
d) Evolution is driven solely by Lamarck’s theory of inheritance of acquired characteristics

Answer 7

c) All living things share a common ancestor and have undergone evolutionary change over time

Question 8

The theory of descent with modification suggests that all living organisms are related through a branching evolutionary tree, reflecting their shared _____ and diversification over time.

Answer 8

ancestry

Question 9

What are the different types of evidence that support the theory of evolution? (Pick 2)

Answer 9

1. Fossil record: Provides a historical record of life forms and shows changes over time.
2. Comparative anatomy: Similarities in body structures of different species suggest a common ancestry.
3. Comparative embryology: Early stages of development in some species share similarities, hinting at a shared evolutionary history.
4. Molecular biology: Similarities in DNA sequences provide evidence for evolutionary relationships.

Question 10

The fossil record:
a) Provides a complete and unbroken record of all life forms
b) Shows evidence of evolutionary change over time
c) Does not support the theory of descent with modification
d) Only includes fossils of recently extinct species

Answer 10

b) Shows evidence of evolutionary change over time

Question 11

Homologous structures are similar structures in different species that share a common _____ _____ but may have different functions (e.g., the wing of a bird and the arm of a human).

Answer 11

evolutionary origin

Question 12

TF: Analogous structures are similar structures in different species that have evolved independently in response to similar environments and serve similar functions (e.g., the wing of a bird and the wing of a butterfly).

Answer 12

True

Question 13

How can vestigial structures, which are reduced or non-functional remnants of organs in some organisms, be evidence of evolution?

Answer 13

Vestigial structures suggest that these organs were once functional in ancestral species but have lost their original function over time due to changes in environment or lifestyle.

Question 14

What is convergent evolution and how does it differ from divergent evolution?

Answer 14

Convergent evolution: Unrelated species evolve similar adaptations in response to similar environments (e.g., streamlined body shapes of dolphins and fish).

Divergent evolution: Species from a common ancestor evolve different adaptations as they radiate into new environments (e.g., finches in the Galapagos Islands with different beak shapes for different food sources).

Question 15

Biochemical similarities, such as shared DNA sequences, can be used to:
a) Only study the function of genes within a single species
b) Disprove the theory of evolution
c) Construct evolutionary trees showing relationships between species
d) None of the above

Answer 15

c) Construct evolutionary trees showing relationships between species

Question 16

_____, the study of the geographic distribution of organisms, can reveal patterns of evolution as species disperse and adapt to new environments.

Answer 16

Biogeography

Question 17

TF: The theory of evolution by natural selection is not static and continues to be refined as new evidence emerges from various fields of science, including genetics, paleontology, and developmental biology.

Answer 17

True

Question 18

How can antibiotic resistance in bacteria be viewed as an example of evolution by natural selection?

Answer 18

When exposed to antibiotics, some bacteria have mutations that allow them to survive. These resistant bacteria can reproduce and pass on their resistance genes to future generations, leading to a population with a higher proportion of resistant individuals. This demonstrates the ongoing process of natural selection leading to adaptations within populations.

Question 19

What are the main mechanisms that can cause changes in allele frequencies within a population, leading to evolution?

Answer 19

Natural selection: Differential survival and reproduction based on heritable traits.

Genetic drift: Random changes in allele frequencies in small populations.

Question 20

Genetic drift can have a more significant impact on:
a) Large populations with high genetic diversity
b) Small populations with low genetic diversity
c) Populations with only beneficial mutations
d) None of the above

Answer 20

b) Small populations with low genetic diversity

Question 21

_____ _____, the movement of alleles between populations, can introduce new genetic variation and influence the course of evolution.

Answer 21

Gene flow

Question 22

TF: Mutations are the ultimate source of new genetic variation within a population. Mutations can alter genes and potentially create new traits that may be acted upon by natural selection.

Answer 22

True

Question 23

How can genetic bottlenecks and founder effects, which are specific types of genetic drift, influence the evolution of populations?

Answer 23

Genetic bottlenecks (reduction in population size due to a severe event) and founder effects (establishment of a new population by a small group of individuals) can lead to a loss of genetic diversity and potentially make the population more vulnerable to environmental changes. In some cases, these events can also lead to rapid evolution if certain alleles become more frequent by chance.

Question 24

What is the process of speciation, and how does it lead to the formation of new species?

Answer 24

Speciation is the evolutionary process by which a single species diverges into two or more distinct species. This can occur through various mechanisms, such as geographic isolation, where populations become separated and evolve independently.

Question 25

Allopatric speciation refers to:
a) Speciation that occurs within the same geographic area, but with reproductive barriers preventing interbreeding
b) Speciation that occurs due to the geographic isolation of populations
c) The process by which a new species arises from an existing species very rapidly
d) None of the above

Answer 25

a) Speciation that occurs within the same geographic area, but with reproductive barriers preventing interbreeding

Question 26

Adaptive _____ is the rapid evolution of a single species into multiple diverse forms that occupy different ecological niches. This is often observed in island ecosystems where new environments favor the evolution of specific adaptations.

Answer 26

radiation

Question 27

The theory of evolution by natural selection helps us understand:
a) How life originated on Earth
b) The process by which populations change over time
c) The meaning and purpose of life
d) None of the above

Answer 27

b) The process by which populations change over time

Question 28

Evolution is a gradual process that occurs over vast stretches of time. The _____ _____ provides snapshots of this process, showing how life forms have changed and diversified throughout Earth’s history.

Answer 28

fossil record

Question 29

TF: Evolution does not necessarily mean progress towards greater complexity. Organisms can evolve adaptations that suit their specific environment, and simpler structures may be more advantageous in some cases.

Answer 29

True

Question 30

Briefly describe the concept of natural selection according to Charles Darwin.

Answer 30

Natural selection is the process by which individuals with heritable traits that better enable them to survive and reproduce in a given environment will tend to leave more offspring than other individuals. This leads to the gradual change of a population over generations.

Question 31

The process by which life arose from non-living matter is called:
a) Natural selection
b) Speciation
c) Abiogenesis
d) Evolutionary adaptation

Answer 31

c) Abiogenesis
Option A acts on existing life, not its origin

Question 32

TF: The theory of endosymbiosis proposes that some organelles within eukaryotic cells, like mitochondria and chloroplasts, originated from free-living prokaryotic cells that became engulfed by another cell, forming a symbiotic relationship that eventually led to a permanent association.

Answer 32

True