Download Fossils Show changes in species over time

Evolution
Evolution means change.
Biological Evolution: The process by which modern organisms
have descended from ancient organisms.
Evidence for Evolution
Fossils – evidence of life in the prehistoric past
Trilobite molds and casts
http://www.discoveringfossils.co.uk/W
hatisafossil.htm
Fossil Evidence
Ammonite Cast
Serpent Starfish cast
Fossil Evidence
Fish Imprint
Fossil Evidence
Hard Parts
Shark Teeth
Dinosaur Teeth
Fossil Evidence
Hard Parts
Mammoth Molar
Mammoth Tusk
Fossil Evidence
Footprints
From Dinosaurs
Fossil Evidence
Microscopic Fossils
Bacteria – 3.5 Billion Years Old
Algae – 1.2 Billion Years Old
Fossil Evidence
Coprolites – Fossilized “Poop”
Dinosaur coprolites
Amber-fossilized tree sap
Fossil Evidence
Whole Organisms
Insects in Amber
Frozen Mammoths
Stefan Lovgren
for National Geographic News
April 8, 2005
Woolly Mammoth Resurrection,
"Jurassic Park" Planned
A team of Japanese genetic scientists aims to bring woolly mammoths
back to life and create a Jurassic Park-style refuge for resurrected
species. The effort has garnered new attention as a frozen mammoth is
drawing crowds at the 2005 World Exposition in Aichi, Japan
Fossils Show changes in species over time
Evolution of the horse
Fossils Show changes in species over time
Evolution of the horse
Two major trends – larger size, fewer toes
Transitional Fossils
Tiktaalik – The fish that found its feet
How Old are the Fossils?
Fossils are usually found in sedimentary rock.
Relative Dating – Older fossils are on the bottom. (Law of Superposition)
Type fossils – If you find the same “type fossils” in two different rock layers,
they are of the same age.
How Old are the Fossils?
Absolute dating: Measure the amount of radioactivity left in rocks.
What does the Fossil Evidence Show?
1. Life has changed throughout Earth’s history.
2. Organisms that are here today are different than
life forms of the past.
3. Different species did not all appear at the same time.
4, Extinction has been a common occurrence throughout Earth’s history.
5. Transitional fossils show links between organisms.
Archaeopteryx
Homologous Structures
Homologous structures – parts shared by different organisms that
have been inherited from a common ancestor. These parts may
have been modified for different uses. (Descent with modification)
humerus
radius
ulna
carpals
metacarpals
phalanges
Tinkering – The Panda’s Thumb
The panda has descended from carnivorous ancestors.
It eats mainly bamboo and has a “thumb” that helps to hold the bamboo.
The thumb is a modification of one of the wrist bones
Analogous Structures
The wing of the butterfly, and the wing of a bird are analogous structures.
Analogous structures have the same function but do not have the same
structure.
The butterfly wings do not have bones, but the bird wing does.
The wings have a different evolutionary past.
Homologous Structures
Analogous Structures
Dog leg
Bat Wing
Dog leg
Human eye
Lizard eye
Whale eye
Insect leg
Octopus eye
Vestigial Structures
Structures found in living organisms which no longer serve a useful function.
They were inherited from an ancestor who did use them.
Tail bone of humans
Rear leg bones and claw on snake
Rear leg bones of whales
Vestigial eyes on blind cave fish
Figure 2.2.2. X-ray image of an atavistic tail found in a
six-year old girl. A radiogram of the sacral region of a six-year old
girl with an atavistic tail. The tail was perfectly midline and protruded
form the lower back as a soft appendage. The five normal sacral
vertebrae are indicated in light blue and numbered; the three coccygeal
tail vertebrae are indicated in light yellow. The entire coccyx (usually
three or four tiny fused vertebrae) is normally the same size as the fifth
sacral vertebrae. In this same study, the surgeons reported two other
cases of an atavistic human tail, one with three tail vertebrae, one with
five. All were benign, and only one was surgically "corrected" for
cosmetic reasons (image reproduced from Bar-Maor et al. 1980, Figure
3.)
http://www.youtube.com/watch?v=I2C-3PjNGok
Vestigial Structures
Bones from the atavistic hind-limbs of a
humpback whale. A. From top to bottom, the
cartiliginous femur, tibia, tarsus, and metatarsal,
arranged as found in situ in the whale. B.
Enlarged detail of the femur and tibia shown in
A. (scale is not the same as A). C. Detail of the
tarsus and metatarsal shown in A.
Embryological Similarities
Embryos of vertebrates show a similar development which indicates common ancestry.
Biochemical Similarities
All living things use DNA and RNA as the genetic material.
All proteins in living things are built on the same 20 amino acids
All living things use the same 3 base code for each amino acid.
All living things use ATP as the direct energy source.
Biochemical Similarities
Hemoglobin is found in all these
vertebrates.
They have some different amino
acids that make up the protein.
The number of amino acid differences
in the hemoglobin protein of two
species is proportional to the length of
time that has passed since they
shared a common ancestor.
The more similar the proteins are, the
more closely related two species
would be.
Humans have a closer evolutionary
relationship to a monkey than they
do to a mouse.
Geographical Distribution
Darwin found 13 different species of finches
in the Galapagos Islands.
They were very similar but each species had
slight differences in their size, beak and feet.
They were also different from the finches found
on the mainland of South America.
The inference is that the ancestors of these
birds made it to the newly formed islands.
Here they evolved into all the species
present on the islands today.
Geographical Distribution
Galapagos Tortoises
Geographical Distribution
Animals that are not closely related sometimes look similar because of similar
environmental conditions which select for similar beneficial traits.
Divergent Evolution
An ancestral species evolves into many different species.
Moose
Elk
White-Tail deer
Mule Deer
Black-Tail deer
Ancestral Deer-like Species
Key deer
Convergent Evolution
Two species that are not closely related appear to be very similar
because they share similar environments.
HUMAN EVOLUTION MYTHS
• MYTH-Humans came from apes.
• MYTH-Human evolution is a ladder with
a series of steps directly leading from
an ancestor to modern humans.
• MYTH-Human characteristics evolved
at the same time.
HUMAN EVOLUTION MYTHS
REVEALED
• Humans and chimps represent 2 divergent
branches of the anthropoid tree that evolved
from a common ancestor
• Not all fossils have been found, some fossils
lead to a dead end. Not a ladder but more like a
bush
• Mosaic evolution- different features evolved at
different times