Natural selection theory

Charles Darwin and Alfred Wallace

Natural selection theory

Alfred Wallace

Charles Darwin

Charles Darwin developed the idea of natural selection. At the same time, another naturalist, Alfred Wallace, independently arrived at the same idea. Both scientists presented their ideas together. Which is why, theory of natural selection is credited to both Darwin and Wallace.

• Why is there so much diversity in life?

• What explains adaptations?

Some of their research questions were:

creative perspective

eliminative perspective

two perspectives of natural selection

1. Environmental conditions determine which organisms can survive.

key aspects about natural selection theory (eliminative perspective)

2. Organisms that survive are able to reproduce and pass on their traits to their offspring.

3. These survivors can continue over time by producing more offspring, ensuring the persistence of their traits.

4. Changes in environmental conditions can pressure organisms to either adapt and survive or face extinction.

5. Variation within a species is crucial for survival. Without variation, an entire population is at risk of dying out of conditions change.

Natural selection (eliminative perspective)

Jungle environment

Activity: a) Draw the jungle environment with its animals. Be sure to include the three types of frogs (blue, pink and green).

Natural selection (eliminative perspective)

b) Draw the degraded jungle and depict the animals you think could survive and reproduce (adapt).

Degraded Jungle environment

Jungle environment

Natural selection (eliminative perspective)

Answer the following questions:1. Which color frog is most likely to go extinct? Why? 2. Which color frog is most likely to survive and reproduce (adapt) in the degraded jungle environment? 3. Why do you think this frog will survive and reproduce (adapt)? 4. Where do you think adaptations come from?

Jungle environment

1. Environmental conditions enable different traits to accumulate in organisms that help them to survive.

key aspects about natural selection theory (creative perspective)

2. These different traits accumulate over time, leading to the emergence of a significant new trait.

key aspects about natural selection theory (creative perspective)

3. When there are changes in environmental conditions, these accumulations help organisms survive and reproduce, leading to adaptations.

key aspects about natural selection theory (creative perspective)

Is the diversity of traits within species. It is important for survival as it allows populations to adapt to changing environments.

variation

environment

Influences the creation of new traits or the elimination of some traits that are not adaptive.

summary

extinction

The adaptations take a lot of time. Thousands or millions of years. When the environment change so fast, there is no time to adapt.

it's not the strongest

adaptation

It's about the most well-adapted to a specific environment.

A heritable trait that improves an organism's ability to survive and reproduce in its specific environment.

summary

Relationships and common ancestry

Natural selection theory was difficult to accept.

The changes are slow. They depend on the environment and what organisms need to survive and reproduce.

changes over time

Indohyus

In fact, all living organisms share a common ancestor: LUCA (Last Universal Common Ancestor)