Transcript Document

Darwin's Theory
·Our anatomy resembles the anatomy of other animals.
·Some of our features,
, have similar structure and function of those of other animals.
such as arms and legs
·Some features, such as
·Charles Darwin anddifferent
goosebumps
, are structurally similar to other animals’ features, but have
functions.
came to similar conclusions about evolution at about the same time.
Alfred Wallace
·In 1859, Darwin wrote about evolution and natural selection in his Origin of Species. He made two
important points in this book:
Species evolve over time.
Species evolve by the process of natural selection.
natural
, inselection
which the fittest pass along
·Evolution occurs through
their traits to their offspring.
·Species tend to produce
offspring, resulting in a competition or a struggle for
existence.
·Only the
excessive
survive to pass along their traits.
·There are
between the individuals in a population, and these can be
variations found in their
offspring.
"strongest"
·A species’ natural surroundings, known as the ecological
variations
which variations are most
successful.
heritable
eg.
iche
cricket - lay more than 200 eggs at a time. Variations in
colour improve survival
n
select
·Darwin used the term
·He described the
as a synonym
“survival
of
of the fittest”
.
natural selection
of an individual as its ability to survive and
reproduce in its environment.
·Darwin
fitness
also believed new species could arise if populations became
.
·Natural selection does not make organisms
.
isolated
·Instead, organisms become
"better"
·There is no ultimate goal, or ideal, to be reached.
better adapted to their
present environment
Jackrabbit's large ears adapted to its hot
environment. Snowshoe hare has camouflage.
Comparative Anatomy
What is similar about the two people in each
image? Write your comparisons and touch the images.
These football players look similar because they do the
same workouts, play the same sport and eat similar food.
They are the similar due to environmental factors.
Homology- Organisms have similar traits due to inheritable genetics from
common ancestors.
Comparisons
Analogy- Organisms have similar traits due to similar environments.
These cousins are similar due
to inheritable traits from a common
ancestor.
Evidence for Darwin's Theory of Evolution
·The fossil record supports the theory of evolution.
·Fossils are the remains or markings left by organisms.
·Most fossils are found in sedimentary rock layers.
·
· The rock layers are called strata
Younger strata are deposited on older strata
Biology Source pg. 192
.
.
(Using the scientific process slide 4 video 1)
http://www.hhmi.org/biointeractive/using-scientific-process-study-huma
evolution
·The fossil record is a chronological collection of the remains of ancient species.
·The oldest chemical evidence of life is
billion years old.
·The oldest fossil evidence of life is
billions years old.
3.8 fossils and recent life.
·
have found many links between ancient
·Fossil evidence is incomplete as usually only hard tissue fossilizes,
and evolutionary links are
3.5
difficult to make.
Paleontologists
App - Nat and Art. selection slide 3
http://www.hhmi.org/biointeractive/natural-and-artificial-selection
Prior to Comparing Anatomy Lab - App - Skeletons Reveal Human &
Chimp slide 7~onwards
http://www.hhmi.org/biointeractive/skeletons-reveal-human-and-chimpanzeeevolution
Create a chart like the one you see below.
Characteristic
Is it Bird - like?
Is it Reptile like?
Is it common to both?
Examine this bird skeleton and list at least two characteristics that help you identify it as a bird.
Look at this illustration of a raptor dinosaur. List three major characteristics of the dinosaur.
Now study the Archaeopteryx drawing. Then fill in the rest of the chart.
According to the fossil record, dinosaurs were present on Earth before birds, although dinosaurs and birds did
coexist. Based on your observations of birds, dinosaurs, and Archaeopteryx, what conclusions do you draw about the
Archaeopteryx fossil?
What is its relationship, if any, to birds and/or dinosaurs? Support your position with the data you have already
collected.
Archaeopteryx :
An Early Bird
Paleontology has helped us understand the unique evolutionary history of birds.
A particulary important and still contentious discovery is Archaeopteryx lithographica, found in the Jurassic Solnhofen Limestone of southern
Germany, which is marked by rare but exceptionally well preserved fossils. Archaeopteryx is considered by many to be the first bird, being of about
150 million years of age. It is actually intermediate between the birds that we see flying around in our backyards and the predatory dinosaurs like
Deinonychus. In fact, one skeleton of Archaeopteryx that had poorly preserved feathers was originally described as a skeleton of a small bipedal
dinosaur, Compsognathus. A total of seven specimens of the bird are known at this time.
It has long been accepted that Archaeopteryx was a transitional form between birds and reptiles, and that it is the earliest known bird. Lately,
scientists have realized that it bears even more resemblance to its ancestors, the Maniraptora, than to modern birds; providing a strong
phylogenetic link between the two groups. It is one of the most important fossils ever discovered.
Unlike all living birds, Archaeopteryx had a full set of teeth, a rather flat sternum ("breastbone"), a long, bony tail, gastralia ("belly ribs"), and three
claws on the wing which could have still been used to grasp prey (or maybe trees). However, its feathers, wings, furcula ("wishbone") and reduced
fingers are all characteristics of modern birds.
As you can see, Archaeopteryx certainly had feathers, although whether these feathers were used for regulating its body temperature
or for flight is a matter still open for debate. Feathers may have originally evolved for insulation and then been co-opted into flight. The
origin of flight, and the actual flight capabilities of Archaeopteryx, are debated. Two models of the evolution of flight have been
proposed: in the "trees-down" model, birds evolved from ancestors that lived in trees and could glide down, analogous to today's flying
squirrels. In the "ground-up" model, the ancestors of birds lived on the ground and made long leaps. For more information, see our new
exhibits on vertebrate flight and avian flight.
The flight stroke may have originated as an extension of the grabbing forearm motions that smaller, agile theropods such as
Deinonychus may have used to grab and hang on to prey. As you know if you've ever cut up a chicken, living birds (except for flightless
birds like the ostrich and kiwi) have a keeled sternum to which the large, powerful flight muscles attach. Archaeopteryx, however, had a
comparatively flat sternum. Although it is currently thought that Archaeopteryx could sustain powered flight, it was probably not a strong
flier; it may well have ran, leaped, glided, and flapped all in the same day.