Transcript Charles Darwin and Evolution

Darwin
and evolution
Some key points
• A change in the genes!!!!!!!!
• Populations evolve, not individuals!
• Happens over long time scales
History
• Biblical scholars worked out the world
was 4004 BC created
• Scientists worked out world is more
than 5 billion years old and life been
around for 2-3 billion.
• Linnaeus 1707
• Lamarck 1744
• Cuvier 1769
• Lyell 1797
• Darwin 1809
• Mendel 1822
• Wallace 1823
1800 all started to happen
Old Theories of Evolution
• Jean Baptiste Lamarck (early 1800’s) proposed:
“The inheritance of acquired characteristics”
• He proposed that by using or not using its body
parts, an individual tends to develop certain
characteristics, which it passes on to its
offspring.
Charles Darwin
• Influenced by Charles Lyell who published
“Principles of Geology”.
• This publication led Darwin to realize that
natural forces gradually change Earth’s
surface and that these forces are still
operating in modern times.
Charles Darwin
• Darwin set sail on the H.M.S. Beagle (1831-1836)
to survey the south seas (mainly South America
and the Galapagos Islands) to collect plants and
animals.
• On the Galapagos Islands, Darwin observed
species that lived no where else in the world.
• These observations led Darwin to write a book.
Evolution by Natural Selection
• Populations tend to have large numbers
of offspring.
• Environmental resources are limited;
and therefore there is competition.
• There is naturally-occurring variation
among individuals in any population.
• Individuals with the best adaptations will
survive and reproduce the most.
Evolution by Natural Selection
• These four basic facts explain how
“successful” alleles get passed down
more often than “unsuccessful” alleles,
hence causing a change in the gene
pool of a population (evolution).