Lec 1

Question 1

What is the definition of Biological evolution?

Answer 1

change in populations inherited traits occurs from one generation to the next.

Question 2

What can be observed for monogenic traits in biological evolution?

Answer 2

Changes in allele frequencies at a particular gene.

Question 3

Is Evolution “just” a theory?

Answer 3

No, scientific theories are backed by multiple lines of evidence and provide overarching explanations for major aspects of the natural world.

Question 4

What are some examples of other scientific theories?

Answer 4

Gravity, Plate tectonics, and Germ theory.

Question 5

Is evolutionary theory widely accepted by biologists?

Answer 5

Yes, evolutionary theory is overwhelmingly accepted by biologists.

Question 6

What supports the evidence for evolutionary theory?

Answer 6

-Predictions extensively tested
-measurable evolutionary changes are sometimes observed within a human lifespan
-preserved in fossils and genomes.

Question 7

How do we know whales are mammals?,

Answer 7

Whales share synapomorphies with mammals, including mammary glands, three middle ear bones, hair (in developing embryos), and similarities with fish arose through convergent evolution because of an aquatic lifestyle.

Question 8

What is the homologous structure in whales to the forelimbs of other tetrapods?,

Answer 8

The pectoral fin in whales is homologous to the forelimbs of other tetrapods.

Question 9

What synapomorphies do fossil whales share with modern cetaceans?,

Answer 9

involucrum
reduced pelvic limbs
long snouts
heterodont teeth like terrestrial carnivores.

Question 10

Do evolutionary biologists search for missing links?,

Answer 10

No, biologists expect the fossil record to be incomplete, and finding direct ancestors is challenging even if they have been preserved somewhere.

Question 11

What evidence supports relationships between current and past species?,

Answer 11

Available molecular, morphological, and embryological evidence

Question 12

How is the cetacean transition from land to water documented?

Answer 12

Through isotopic analysis of fossil teeth and fossil analysis of hind limb loss.

Question 13

What does isotopic analysis of fossil teeth reveal about marine animals?

Answer 13

marine animals have a higher O18/O16 ratio in their teeth due to their consumption of saltwater.

Question 14

What happens to hindlimbs in embryos during cetacean evolution?

Answer 14

Hindlimbs begin to form in embryos but do not fully develop; instead, they are reabsorbed by week 9.

Question 15

Is the idea that organisms are perfectly adapted to their environment true?

Answer 15

No, natural selection works with available genetic variation and is constrained by the laws of physics and developmental programs.

Question 16

What are examples of whales with vestigial legs?

Answer 16

Ambulocetus is a fossil whale with legs, and Basilosaurus had vestigial legs.

Question 17

Do dolphin embryos develop hind limb buds?

Answer 17

Yes, dolphin embryos still make hind limb buds that disappear later in development.

Question 18

Does evolution happen for the good of the species?

Answer 18

No, natural selection operates on traits that are beneficial for individuals or their genes in a particular environment.

Question 19

What happens to traits that are bad for individuals?

Answer 19

Traits that are bad for individuals (or genes) will not be selected for, even if they would be good for the species.

Question 20

What is the result of competition for mates?

Answer 20

Competition for mates can lead to sexual selection, promoting the evolution of certain traits.

Question 21

What is one reason for the evolution of large brains?

Answer 21

Sociality, as forming lasting alliances through kin selection and complex communication required a large brain.

Question 22

Are organisms perfectly adapted to their environment?

Answer 22

No, natural selection works with available genetic variation and is constrained by the laws of physics and developmental programs.

Question 23

Why do whales have a large brain size relative to other vertebrates?

Answer 23

complex social behavior and language but comes at a high metabolic cost.

Question 24

What lineage of whales lost teeth and developed baleen?

Answer 24

The Mysticetes lineage of whales lost teeth and completely replaced them with baleen.

Question 25

What can cause maladaptation of small populations?,

Answer 25

Genetic drift can cause maladaptation of small populations.

Question 26

Do individuals continually adapt to their environment?,

Answer 26

No, evolution works on inherited traits, and acquired changes are not passed to offspring.

Question 27

What results in evolution?,

Answer 27

Evolution results from changes in allele frequencies.

Question 28

Why do long-lived organisms living in small populations often go extinct?,

Answer 28

They cannot usually adapt to rapid evolutionary changes in their environment, which can lead to extinction.

Question 29

What increases the risk of extinction for some cetacean species?,

Answer 29

Small population sizes increase the risk of extinction for some cetacean species, as seen in North Atlantic right whales.

Question 30

How many North Atlantic right whales remain?,

Answer 30

Fewer than 350 North Atlantic right whales remain.

Question 31

What factors have contributed to the high mortality of North Atlantic right whales?

Answer 31

boat collisions, rope or line entanglements, and aging of the female population.

Question 32

What are some key points about biological evolution?

Answer 32

between-generation changes in the heritable traits of a population.

Question 33

What challenges do whales face in adapting to their environment?

Answer 33

Whales evolve slowly and may not be able to adapt to rapid changes in their environment, such as whaling.

Question 34

What are the consequences of a high metabolic cost for a large brain?

Answer 34

A high metabolic cost for a large brain requires a high density of high-calorie prey.

Question 35

Did the ancestors of all modern whales have teeth?

Answer 35

Yes, the ancestors of all modern whales had teeth.

Question 36

What replaced teeth in the Mysticetes lineage of whales?,

Answer 36

Baleen completely replaced teeth in the Mysticetes lineage, as genes for building teeth were disabled by mutations.