2. Jean-Baptiste Lamarck
(France - 1744-1829)
Based theories on observations of
similarities between ancient fossils
and modern animals, vestigial
structures and passing on of desired
traits by selective breeding
Proposed than an individual gains
or loses traits during its lifetime
which are then passed on to its
offspring.
Believed evolution is a constant
process striving toward greater
complexity and perfection.
3. Jean-Baptiste Lamarck
Mechanisms of Change:
Law of Use and Disuse
Body parts most frequently used become stronger and more
developed and parts used less are reduced.
Ex. Penguins wings – Small due to disuse.
Transmission of Acquired Characteristics
Qualities acquired during an organisms life time are passed down to
offspring
Ex. Parents who develop strong muscles will pass strong muscles down
to offspring
4. Jean-Baptiste Lamarck
Important contributions to evolutionary theory:
Organisms change over time
Organisms adapt to their environment
Traits found in parents are passed to offspring
What Lamarck got wrong:
Evolution tends towards perfection & complexity
Organisms are constantly evolving
Acquired characteristics are passed on
5. Pre-Darwinian Ideas About Evolution:
Life has existed on Earth for a long time
Organisms have changed since the dawn of life
Many extinctions have happened since life began
Fossil evidence, embryology and comparative anatomy
show similarities between related species and suggest a
common ancestor.
Mendel’s work with genetics showed how genetic
elements are passed through generations
6. Charles Darwin
(England 1809-1882)
Naturalist
1831: Embarked on 5 year
around the world voyage
aboard the HMS Beagle.
Studied the diversity of life
with a particular focus on the
Galapagos Islands
Returned home to continue
his research
1859: Published On the
Origin of Species
8. Galapagos Islands
Group of Volcanic Islands off the coast of South America
Darwin observed variation between the animals species
on each of the islands and the mainland
Famously, he observed, collected and measured the
many different species of finches found on the islands
10. Darwin’s Finches
Noticed huge variation in beak type and size
Beak type correlated with the type of food source on
each island
Hypothesized the beak type had adapted to the type of
food available in the finch habitat
Led to theory of Natural Selection
11.
12. Alfred Russell Wallace
Darwin wasn’t the only one putting all the pieces
together…
https://www.hhmi.org/biointeractive/origin-species-making-
theory
(30 min)