Transcript Ch. 13 Evidence for Evolution.pp

EVOLUTION:
An Introduction
EVOLUTION
• Chapter 13: Evolution: Evidence
of Change
• Chapter 14: Evolution: How Change
Occurs (Process of Evolution)
EVIDENCE OF EVOLUTION:
1. Ability to artificially
select (breed)
Canis lupus
2. Geographic distribution
of similar species
Family Culicidae
a.k.a. ___________?
EVOLUTION: Evidence Of
Evolution
3. Fossil Record
4. Homologous structures
show common
ancestors
(Comparative Anatomy)
EVOLUTION: Evidence Of
Evolution
6. Embryology:
development
of embryonic
structures
(developing
embryos
undergo
evolutionary
changes)
EVOLUTION: Evidence Of
Evolution
7. Chemical Relationships:
- DNA
- amino acids in protein
e.g. cytochrome c
hemoglobin
• 8. vestigial organs: organs that an organism
has no use for (may resemble miniature legs,
tails, etc.)
• as evolutionary change takes place, species
develop new adaptations that make some
organs unnecessary (e.g. snakes have leg buds
implying that their ancestors had feet, Figure 1319, p. 285)
Evolution and Life’s Diversity
Evolution:
- the process by which modern organisms
have descended from ancient organisms
- Charles Darwin contributed the most to
evolution
Darwin’s Dilemma
• Englishman (1809-1882)
• he studied animals while cruising the world
on the HMS Beagle
• collected animal and plant specimens
• wrote and read many books on his voyage
Diversity of Life
• the variety of living things is called the
diversity of life
• how many organisms exist on earth?
(~3-20 million different living species)
• Darwin discovered that many organisms
had vanished from the Earth
• Dodoes are now extinct
Fitness: To Survive and
Reproduce
• the physical traits and behaviours that
enable organisms to survive and
reproduce in their environment give them
what Darwin called fitness
• Darwin published his theory in 1859, 30
years after his voyage began, in his book
entitled “The Origin of Species”
• http://www.literature.org/authors/darwincharles/the-origin-of-species-6th-edition/
Fitness: To Survive and
Reproduce
• Principle of Common Descent: species
have descended from common ancestors
• fitness arises through adaptation
(e.g. giraffes developed long necks over
time leading to the giraffe we know today)
Summary
• the observations of the diversity of living
things on earth contributed to the
formation of Darwin’s theory of Evolution
• fitness is the combination of physical traits
and behaviours, or adaptations that help
organisms survive
The Age of The Earth:
The Geological Time Scale: A Clock in the Rocks
• geological time scale: helps biologists
and geologists date the Earth’s past with
the help of a record in the rocks
• relative dating: a technique scientists
used to determine the age of fossils
relative to other fossils in different layers of
rock
The Age of The Earth:
Radioactive Dating
• radioactive dating: the traces of
radioactive isotopes enable scientists to
calculate the actual age of a sample
• scientists estimate that the Earth is 4.5
billion years old
• scientists divided the 4.5 billion years into
Eras ( Cenozoic/Mesozoic/Paleozoic
/Precambrian) …Periods…Epochs…
• (Can’t Make People Perfect)
The Fossil Record
How Fossils Form
• the material surrounding the dead organism
often preserves it
• most fossils are found in sedimentary rock
• sedimentary rocks are formed when exposure to
rain, heat, and cold breaks down existing rocks
into small particles of sand, silt and clay
• these particles are carried by streams and rivers
and they settle at the bottom of the lake or sea
Evidence from Living
Organisms
• all living organisms carry within their bodies
traces of the history that links them to their
ancestors