Evolution Joke
Evolution

Jean-Baptiste Lamarck was the first to
propose evolution

He believed that the mechanism for
evolution was the inheritance of
acquired traits
◦ E.g. A Body Builder would have children born
with larger muscles
Darwin and Evolution
Darwin & Evolution
1. Different species of an organism are
descendants from an ancestral species.
 In other words, species evolve over time.
 Known as descent with modification.
2. Evolution occurs by natural selection.
Lamarck Vs. Darwin
Point 1: Descent With Modification
(a.k.a. Evolution)

Occurs when a species of an organism
accumulates modifications (i.e. mutations)
which help it adapt to the environment

Must affect an entire population’s gene pool in
order to be considered evolution.
Point 2: Natural Selection

Individuals with characteristics well suited
to the environment leave more offspring
on average than those less adapted to the
same environment.

Based on three observations:
A.
The Struggle for Existence
B.
Natural variations among members of a
species
C.
Environmental influence on evolution
A. The Struggle For Existence

Species tend to produce more offspring
than can survive.
◦ Therefore individuals will compete with one
another for limited resources
E.g. Frog Eggs
Demonstration
B. Natural Variation

Species are inherently different from one
another. The organism best adapted to a
particular environment has the best
opportunity to survive and reproduce.

This is referred to as fitness level.
Who has the selective reproductive
advantage?
Which is More “Fit”

Environment A: Hot climate

Environment B: Cold climate
Test Your Knowledge: Which is
More “Fit”

Environment A: Consists of many predators
adapted to poisonous prey.

Environment B: A marsh
Survival of the Fittest: Asian
Carp Case Study
Survival of the Fittest: Asian
Carp Case Study
Asian Carp Adaptations

Feed on algae and
plankton (food chain
impact)

Reproduce very quickly

Can consume 1/5 of
their weight per day

Can grow over 100
pounds over their
lifetime
C. Environment

The environment determines which trait will
be advantageous or harmful

In this way the environment exerts a
selective pressure on a population

Case and point: Peppered Moth
Environment: Peppered Moth
Case Study (Read Aloud)
Before Industrial Evolution:

Original peppered moth was light
coloured

They camouflaged with the light
coloured trees and lichens.
During Industrial Evolution:

Black soot covered trees and
lichens died.
◦ Moths that were dark coloured were
harder to find (hid from predators)
and thus better adapted to the
environment.
Artificial Selection

The process in which humans select the
traits and breed organisms together to
produce a desired result.

E.g. Food Crops
that produce
better yield
Homework/In-class work
1.
Read page 310 and summarize the
consequences of artificial selection
2.
Answer #1-5, 7, 13 (page 311)