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)
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