Transcript Charles Darwin and his Voyage

Charles Darwin and his Voyage
Background on Charles Darwin
• As a youth, Darwin struggled in school
• Father was a wealthy doctor
• At age 16, Darwin entered school to study
medicine but was horrified by surgery
• Darwin’s interests lay with the natural
sciences
• 1827, Darwin was sent to Cambridge
University to become a minister.
Darwin’s Voyage
• 1831, Darwin’s professor recommended him
as an unofficial naturalist on a voyage on the
HMS Beagle.
Darwin’s contributions
• Darwin developed a scientific theory of
biological evolution that explains how modern
organisms evolved over long periods of time
through descent from common ancestors.
Patterns of biodiversity
• 1. Species vary globally
– Noticed that different, yet ecologically similar
animal species inhabited separated but
ecologically similar habitats around the globe
– Ex. Flightless birds , the rhea of South america, the
ostriches on Africa, the emu on Australia
Patterns of Biodiversity
• 2. Species vary locally
– Noticed that different, yet related, animal species
often occupied different habitats within a local
area.
• Tortoises – shells
designed for where they
live and what they eat.
Patterns of Biodiversity
• 3. Species vary over time
– Noticed that some fossils of extinct animals were
similar to living species.
– Fossil record
– Glyptodont and the
armadillo
Darwin’s voyage
• Sailed on Dec. 27, 1831
• 5 years, collect samples, took many
observations
• 1859, published his ideas in a book called “On
the Origin of Species by Means of Natural
Selection”
Influences
• In Darwin’s Day, the thought was that
the earth was only a few thousand years
old and not much had changed.
• Geologist James Hutton - - hypothesis on how
geological processes have shaped the Earth.
– Proposed forces beneath Earth’s surface can push
rock layers upward, over long periods of time =
mountain ranges
Charles Lyell
• Wrote Principles of Geology in 1830, building
off the work of Hutton
• Geological processes we see today mush be
the same ones that shaped Earth millions of
years ago.
Jean Baptist Lamarck
• Suggested organisms could change during
their lifetimes by selectively using or not using
various parts of their bodies.
• Pass acquired traits on to their offspring,
enabling species to change over time =
inheritance of acquired traits
• Ex. Giraffe neck
• Why was this proven wrong??
Thomas Malthus
• Economist
• Reasoned that if the human population grew
unchecked, there wouldn’t be enough living
space and food for everyone.
• This does not happen, why?
• Darwin realized that most organisms do not
survive and reproduce, which do and why…
survival of the fittest.
Artificial Selection
• Nature provides the variations and humans
select those they find useful
• Ex. Breeding horses, dogs…
• Darwin realized that the natural variations
among individuals was very important
because it provided raw material for
change…evolution!
Evolution by Natural Selection
• 3 points that went into Darwin’s theory
– The struggle for existence
– Variation and adaptation
• Adaptation – any heritable characteristic that increases
an organism’s ability to survive and reproduce in its
environment.
– Survival of the fittest –
• How well an organism can survive and reproduce in its
environment.
Natural Selection
• Process by which organisms with
variations most suited to their local
environment survive and leave more
offspring.
Descent with modification
• Darwin suggested that over many generations,
adaption could cause successful species to
evolve into new species.
• Principle of common descent – all species,
living and extinct- are descended from ancient
common ancestors.
Evidence for Evolution
• Biogeography – study of where organisms live
now and where they and their ancestors lived
in the past.
• Patterns in the distribution of living and fossil
species tell us how modern organisms evolved
from their ancetors
Fossil Evidence
• Many recently discovered fossils form series
that trace the evolution of modern species
from extinct ancestors.
• Downfall to using fossils, hard to find
complete set
Comparative Anatomy
• Homologous structures – structures shared by
related species and have been inherited from
a common ancestor
– Same structure – different function
• Vestigial structures – inherited from ancestors
but lost much or all of original function
– Hip bones of dolphin
Embryology
• Looking at developmental stages of many
animals with backbones.
• Similar patterns of embryological
development provide further evidence that
organisms have descended from a common
ancestor.
Biochemistry
• New science, looking at DNA, RNA and
proteins, beyond Darwin’s time.
• At the molecular level, the universal genetic
code and homologous molecules provide
evidence of common descent.