Karl Ernst von Baer
First rigorous
generalization in
comparative
developmental
biology
Karl Ernst von Baer
First rigorous generalization in
comparative developmental biology
Showed that adults of more recently evolved
species often differ markedly from adults of
more primitive species
Argued that embryos of more recently
evolved species often closely resemble the
embryos of more primitive species
Charles Darwin - born in
1809
Charles Darwin
1836
Circumnavigated the
globe aboard
the H.M.S.
Beagle
1831-
Charles Lyell
Highly influential
geologist
Introduced the notion
of uniformitarianism
Gave Darwin the gift
of time
Thomas Malthus
In 1798, he wrote An
Essay on the
Principle of
Population
Charles Darwin
1838
Darwin’s notebooks mention natural
selection
Charles Darwin


1844
Darwin drafts a manuscript laying
out his ideas at length.
The manuscript remains
unpublished until . . .
Alfred Russel Wallace
1858
Wallace sends
Darwin a letter
from Malaysia
with idea of
natural
selection
described
Charles Darwin
1859
Publishes The Origin of the Species
that claims that natural selection
causes adaptive evolutionary change
Gregor Mendel
Uses pea genetics to
show that genes behave
like particles present as
two copies
Darwin either failed to
read Mendel’s paper or
did not realize the
significance of the paper
1866
Ernst Haeckel
Publishes on general
morphology of
organisms and states
his biogenetic law:
ontogeny recapitulates
phylogeny
Correns, Tschermak and
de Vries
1900
Rediscover Mendel’s laws