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.

·In 1859, Darwin wrote about evolution and natural selection in his Origin of Species. He made two important points in this book:

·Some features, such as , are structurally similar to other animals’ features, but have functions.·Charles Darwin and came to similar conclusions about evolution at about the same time.

such as arms and legs

goosebumpsdifferent

Alfred Wallace

Species evolve over time.

Species evolve by the process of natural selection.

·Evolution occurs through , in which the fittest pass along their traits to their offspring.

·Species tend to produce offspring, resulting in a competition or a struggle for existence.

·Only the survive to pass along their traits.

·There are between the individuals in a population, and these can be variations found in their offspring.

·A species’ natural surroundings, known as the ecological n select which variations are most successful.

eg.

natural selection

excessive

iche

variationsheritable

cricket - lay more than 200 eggs at a time. Variations in colour improve survival

"strongest"

·Darwin used the term as a synonym of .

·He described the of an individual as its ability to survive and reproduce in its environment.

·Darwin also believed new species could arise if populations became .

·Natural selection does not make organisms .

·Instead, organisms become

·There is no ultimate goal, or ideal, to be reached.

Jackrabbit's large ears adapted to its hot environment. Snowshoe hare has

camouflage.

“survival of the fittest”natural selection

fitness

isolated

"better"

better adapted to their

present environment

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.

These cousins are similar due to inheritable traits from a common ancestor.

ComparisonsHomology- Organisms have similar traits due to inheritable genetics from common ancestors.Analogy- Organisms have similar traits due to similar environments.

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 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.· have found many links between ancient fossils and recent life.·Fossil evidence is incomplete as usually only hard tissue fossilizes, and evolutionary links are difficult to make.

The rock layers are called strataYounger strata are deposited on older strata

3.53.8

Paleontologists

App - Nat and Art. selection slide 3

Prior to Comparing Anatomy Lab - App - Skeletons Reveal Human & Chimp slide 7~onwards

(Using the scientific process slide 4 video 1)

Biology Source pg. 192

http://www.hhmi.org/biointeractive/using-scientific-process-study-human-evolution

http://www.hhmi.org/biointeractive/natural-and-artificial-selection

http://www.hhmi.org/biointeractive/skeletons-reveal-human-and-chimpanzee-evolution

Characteristic Is it Bird - like? Is it Reptile - like?

Is it common to both?

Create a chart like the one you see below.

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.