Chapter 1

Question 1

What is evolution?

Answer 1

• Evolution is a change in allele frequency in a population over time!
• Alleles are the different possibilities for a given trait
• Every trait has at least two alleles (one from the mother and
one from the father)
• Example: Eye color (e.g., brown, blue, green, hazel)
• Examples of Alleles
• A = Brown eyes
• a = Blue eyes
• B = Green eyes
• b = hazel eyes

Question 2

What did Darwin contribute to our understanding of evolution?

Answer 2

Darwin’s contribution was the

mechanism: Natural Selection*

Question 3

How does natural selection work?

Answer 3

Natural Selection
1. There is a struggle for existence
2. There is variation in features
related to survival and
reproduction
3. This variation is passed from
generation to generation
Result = adaptation

Question 4

Can small changes accumulate to produce complex adaptations?

Answer 4

Demonstrates each change, building on previous small changes, can produce complex adaptations.

Question 5

How fast does evolution happen?

Answer 5

• Evolution occurs across multiple generations
• Look for differences in allele frequencies
• Multiple factors can bring about change
• These mechanisms of evolution are often called the “forces of evolution”
because they drive evolutionary changes
• Multiple forces of evolution often act simultaneously in real life

Question 6

What were some of the problems Darwin experienced in explaining adaptation?

Answer 6

darwin thought it would reduce variation throughout offspring however he had a limited knowledge of genetics and how the allele frequency change over time. also, the environment has a role as well.

Question 7

Know the examples of the finches on Daphne Major for understanding selection and adaptation

Answer 7

Drought reduced the amount of food available
to ground finches, ensuring that not all would
survive
Postulate 1: Struggle for existence
• 1,200 birds reduced to 180

Postulate 2: Variations
• Beak depth varied in the population of ground finches
• Affected survival
• Deep beaks could crack open the hard seeds
• Shallow beaks couldn’t
• Finches with shallow beaks were dying

• Postulate 3: Variation passed on
• Beak depth passed from parent to
offspring

Question 8

Adaptations

Answer 8

• Adaptations help an organism
survive and reproduce
• Result from selective
pressures (natural
selection)
• Complex adaptations are
highly improbable

Question 9

Natural selection

Answer 9

Natural Selection
1. There is a struggle for existence
2. There is variation in features
related to survival and
reproduction
3. This variation is passed from
generation to generation
Result = adaptation

Question 10

Equilibrium

Answer 10

A steady state in which the composition of the population does not change.

Question 11

Morphology

Answer 11

an organism’s size, shape, and composition.

Question 12

Stabilizing selection

Answer 12

The process that produces this equilibrium state is called stabilizing selection.

Question 13

Traits

Answer 13

• Evolution occurs in traits
• A trait is a physical attribute of an organism that is
expressed by genes and/or influenced by the
environment
• Some traits might be evolving and others aren’t
• Population doesn’t evolve! It is a trait (or many)
that is evolving within a population

Question 14

Characters

Answer 14

A trait or attribute of the phenotype of an organism.

Question 15

Species

Answer 15

Species are a dynamic, changing

population of individuals

Question 16

Fecundity

Answer 16

is the term demographers use for the ability to produce offspring.

Question 17

Continuous variation

Answer 17

• Continuous variation: variation in which one form grades
into the next
• Think of a smooth bell curve
• Examples: human height and Darwin’s finches’ beak
depths

Question 18

Discontinuous variation

Answer 18

• Discontinuous variation: when there are different types
with no intermediates
• Example: blood groups or an elephant’s tusks (or no
tusks)

Question 19

Convergence
Placental mammals
Marsupials

Answer 19

• Occurs when similar adaptations emerge in unrelated species
• Marsupial wolf
  * Wolf from Australia
  * Wolves from Eurasia and North America
• Eyes
• Polar bear, seal, and fish

Question 20

Blending inheritance

Answer 20

A model of inheritance widely accepted during the 19 century, in which the heredity material of the mother and father was thought to combine irreversibly in the offspring.