Evolution Part 1 — Foundations & Evidence

Question 1

Define biological evolution.

Answer 1

Descent with modification: changes in a population’s gene pool over generations, leading (over long time) to new species.

Question 2

Define micro-evolution vs macro-evolution.

Answer 2

Micro = change in allele (gene) frequencies within a population from generation to generation; Macro = descent of different species from a common ancestor over evolutionary time.

Question 3

Why is evolution called a scientific theory?

Answer 3

It’s a well-supported explanation built from multiple independent lines of evidence and is refined when new evidence appears.

Question 4

List six scientific lines of evidence for evolution.

Answer 4

Fossil record; Biogeography; Comparative anatomy (homologous/analogous/vestigial); Comparative embryology; Genetics/DNA & molecular evidence; Modification by descent/natural selection.

Question 5

What does the fossil record show? What do they support?

Answer 5

A timeline of life and change through time (from simple to more complex forms), supporting common ancestry and transitions.

Question 6

What’s the value of biogeography?

Answer 6

The geographic distribution of species supports descent from nearby common ancestors (e.g., island endemics).

Question 7

Homologous vs analogous structures?

Answer 7

Homologous: same structure, different function → common ancestry (divergent evolution). Analogous: different structure, same function → convergence, not common ancestry.

Question 8

What are vestigial structures?

Answer 8

Reduced structures with little/no function that reflect ancestry (e.g., human coccyx).

Question 9

What does molecular/DNA evidence show?

Answer 9

The more similar the DNA/proteins, the more closely related the species.

Question 10

Approx. when did life begin on Earth?

Answer 10

~3.6 billion years ago.

Question 11

Name two ways rocks/fossils are dated.

Answer 11

Radiometric dating; Carbon-14 (for relatively recent organic remains).

Question 12

Which four figures must you know for the development of evolutionary theory?

Answer 12

Erasmus Darwin; Jean-Baptiste Lamarck; Charles Darwin; Alfred Russel Wallace.

Question 13

What did Erasmus Darwin suggest?

Answer 13

Species change from earlier forms and share common ancestry (early idea of descent).

Question 14

Summarise Lamarck’s ideas.

Answer 14

Use & disuse + inheritance of acquired characteristics: organisms change during life to suit the environment and pass those changes to offspring (now rejected in genetics; historically important).

Question 15

What did Wallace contribute?

Answer 15

Independently conceived natural selection; his letter spurred Darwin to publish.

Question 16

What is Darwin’s central mechanism?

Answer 16

Natural selection acting on heritable variation leads to adaptation and speciation over time.

Question 17

Why are islands (e.g., Galápagos) famous in evolution?

Answer 17

Isolation, new niches and limited resources promote adaptive radiation and divergence.

Question 18

State the essence of natural selection.

Answer 18

More offspring are produced than can survive; individuals with advantageous heritable traits survive and reproduce more. In reproducing, passing on desirable traits to their offspring, shifting allele frequencies within the population. Resulting in, over evolutionary time, speciation to occur/ significant phenotypic/ genotypic changes within the population.

Question 19

What is artificial selection?

Answer 19

Human-directed breeding that mimics natural selection (selecting for desired traits).

Question 21

Give two different evidence types that support common ancestry and explain each briefly.

Answer 21

Fossils (dated sequences show change over time); Comparative anatomy (homologous structures indicate descent from a common ancestor).

Question 22

Explain why Galápagos finches are a classic example of divergence.

Answer 22

From a common ancestor, different beaks evolved for different niches → divergent evolution/adaptive radiation.

Question 23

In a mixed list, identify which terms indicate divergent vs convergent evolution and justify one.

Answer 23

Divergent = homologous structures/common ancestry; Convergent = analogous structures/similar function without common ancestry.

Question 24

Define the term “Adaptive Radiation”.

Answer 24

A process in which species evolve rapidly to exploit empty ecological niches.

(I.e. Darwin’s Galapagos Finches)

Question 25

What did most people on earth beleive about evolution prior to Darwin and Wallace’s theory of Natural Selection.

Answer 25

That life spontaneously appeared on Earth and this was unrelated to other things.