Scribd
Upload
200 views15 pages

15-1 Darwins Theory

Darwin developed the theory of evolution by natural selection based on observations from his voyage on the HMS Beagle. During the voyage, Darwin noticed that related but distinct species inhabited different islands in the Galapagos, suggesting gradual adaptation to local environments over time. Inspired by artificial selection used by breeders, Darwin proposed that natural selection works in nature by favoring beneficial variations that help organisms survive and reproduce, leading to the emergence of new species. He published his theory in On the Origin of Species in 1859, explaining evolution as change over generations and natural selection as a mechanism driving evolutionary change.

Uploaded by

api-342334216
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
200 views15 pages

15-1 Darwins Theory

Darwin developed the theory of evolution by natural selection based on observations from his voyage on the HMS Beagle. During the voyage, Darwin noticed that related but distinct species inhabited different islands in the Galapagos, suggesting gradual adaptation to local environments over time. Inspired by artificial selection used by breeders, Darwin proposed that natural selection works in nature by favoring beneficial variations that help organisms survive and reproduce, leading to the emergence of new species. He published his theory in On the Origin of Species in 1859, explaining evolution as change over generations and natural selection as a mechanism driving evolutionary change.

Uploaded by

api-342334216
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 15

15.

1 Darwin’s Theory of
Evolution by Natural Selection
Darwin on the HMS Beagle
•  Darwin’s job on the Beagle was to be
a naturalist, and to collect biological
and geological specimens during the
travels.!
•  When Darwin began his journey in
1831, most people thought the world
was ~6000 years old, and that
animals and plants were unchanging. !
The Galápagos Islands
The different islands all had their
own, slightly different varieties of
animals. !
artificial selection
breeding to
produce offspring
with desired traits!
Darwin thought if humans could
change species by artificial
selection, then the same could
happen in nature.!
New species could appear through
small changes in ancestral species.!
Darwin described a process where
some competitors would be better
equipped for survival than others,
those less equipped would die. !
natural selection: organisms
with favorable variations
survive, reproduce, and pass
their variations to the next
generation !
Darwin’s 4 Principles of natural selection:
• Individuals show variation!
• Variations are inheritable!
• More offspring are born than can
survive!
• Variations that increase
reproductive success will be more
common in the next generation!
The Origin of Species
Darwin published On the Origin of
Species by Means of Natural
Selection in 1859. !
Evolution- change in a group of
organisms over time!
Natural selection ≠ evolution!
it is one way evolution can occur !

You might also like