Part 1 of lecture slides for Mr. Mason's Biology I, Hon. class

1. Theory of Evolution
part 1

2. Science v.s. Pseudoscience
Logical process to determine the
cause(s) of natural events in the
world.
observation
question
constant hypothesis testing

3. evolution
not a new idea
life on earth
changes over time
it connects the present with the
past
the unifying theory for the study of
biology

4. Charles Darwin
1809-1882
ships naturalist
on the HMS
Beagle 1831
keen powers of
observation
and analysis

5. Darwin’s visit to tropical South America piqued his
interest in the Diversity of Life.
scientist speculate as many as 10 mi!ion species
Darwin also found evidence to speculate that a large
number of species were once here but vanished.
researches today suspect that of a! the species that onc"
lived on earth 99.9% are now extinc$

6. Darwin wondered
From where does
this seemingly
endless variety of
life come ?
Why have so
many of them
disappeared?
'What a life of wonder - every object new'. Tennyson

7. Jean Baptiste Lamarck
1744-1829
agreed with the
fact of evolution
individual
strived for
perfection
inheritance of
acquired
characteristics

8. Darwin proposed
Descent with Modification
there were a variety of ways in
which organisms were designed for
survival (form and behavior)
organisms appeared well designed
to survive their local environment
survival was necessary for
reproductive success

9. “fitness”
...the combination of physical traits
and behaviors that helps organisms
survive and reproduce in their
environment (adaptation)

10. “fitness”

11. Theory of Natural
Selection
more offspring are born than can survive
genetic variation within a population
competition for resources - “struggle for
existence”
differential reproduction - the best
adapted survive to reproduce

12. The Origin of Species by Means of
Natural Selection
Darwin maintained
that organisms have
been produced
through the long,
slow process of
change in the
species over time -
Evolution

13. Darwin argued that just as each new
organism comes from an existing
organism...

14. ...each species has descended from other
species.
speciation
“Early” modern horse types