Darwinian Insights on Evolution

Question 1

What are Darwin’s 4 key insights on evolution?

Answer 1

1. endless variation
2. heritable variation
3. competition for resources
4. adaptive heritable traits get propagated more in offspring (natural selection)

Question 2

Darwin’s key insights:
1. Endless variation

Answer 2

Characteristics of different organisms vary in endless ways: size, speed, strength, aspects of appearance, visual abilities, hearing capacities, digestive processes, and cell structure.

Question 3

Darwin’s key insights:
2. Heritable variation

Answer 3

Many of these varying characteristics are heritable; they tend to be passed down from one generation to the next.

Question 4

Darwin’s key insights:
3. Competition for resources

Answer 4

-Organisms tend to produce more offspring than local resources could support (e.g., food and living space availability).

-As a population increases and resources are scarce, competition for resources intensifies.

*this led Darwin to his grand insight; variations in hereditary traits might affect organisms’ ability to win in the fight for resources, and ultimately, survive and reproduce.

Question 5

Darwin’s key insights:
4. Adaptive heritable traits get propagated more in offspring (natural selection)

Answer 5

if a trait contributes to an organism’s survival or reproductive success, organisms with that trait will produce more offspring than those without the trait (or less of the trait), causing a gradual increase in the trait’s prevalence over generations resulting in evolutionary change.

Question 5

Natural Selection (definition & examples of advantageous traits)

Answer 5

def: the process where organisms with advantageous traits are more likely to survive and reproduce, leading to evolutionary changes over time.

example 1: peacock plumage provides reproductive advantage as it attracts mates.

example 2: an owl’s camouflage ability provides a survival advantage as it protects itself from predators.

Question 6

Natural Selection (noteworthy points)

Answer 6

-natural selection operates at the population level; it does not occur in an individual, but rather it is a process that affects an entire gene pool of a population.

-natural selection is gradual; change does not occur overnight. slight adaptations accumulate over generations, leading to significant evolutionary changes without sudden shifts.

-“hot-button implications”: the concept of natural selection stirs up controversy because it does not align with the idea of divine creation, and also because it describes humans as having overlap in ancestry with other species. *although it is widely accepted among scientists.

Question 7

Fitness

Answer 7

-an organism’s ability to survive and reproduce in its environment.

-the more offspring an organism has that survive to reproduce, the higher its fitness.

*survival is only important if it contributes to reproductive success.

*“survival of the fittest”