Presentation on theme: "Essential Question: How do scientists define and support the theory of evolution?"— Presentation transcript:
1Looking at the two pictures, can you describe how this form of communication has changed over time?
2Essential Question: How do scientists define and support the theory of evolution? Standards:S7L5a. Explain that physical characteristics of organisms have changed over successive generations (e.g. Darwin’s finches and peppered moths of Manchester)S7L5c. Trace evidence that the fossil record found in sedimentary rock provides evidence for the long history of changing life forms.
3Give an example of how Earth has changed over time. Describe the evidence scientists use to determine that Earth changes over time.Give an example of how Earth has changed over time.
4Evidence of life’s history on earth is provided by fossils. Fossils are the remains of organisms preserved in the earth.
5Fossils can consist of bones, bone fragments, imprints, and preserved remains.
6Most fossils are found in sedimentary rock. Why? Fossils are primarily found in sedimentary rocks because these rocks form at low temperatures and pressures.Students learned about the different types of rocks in 6th grade science. Use their previous knowledge of rocks to guess why most fossils are found in sedimentary rock.
7Some organisms become fossilized in ice or amber.
8Scientists observe fossil characteristics and make inferences concerning the life of the organism based on these observations.
9Once scientists piece the fossil below together, what might they be able to know about the once living organism?It is a relatively large animal which indicates the other types of organisms on earth at that time. The organism eats meat because it has sharp teeth
10How can scientists tell that the first organisms lived in oceans, or that dinosaurs lived on land and that they disappeared 65 million years ago?These questions and others can be addressed by determining the age of fossils.Scientists use relative dating and absolute dating to describe the age of fossils.
11Older fossils are found in deeper layers of the earth’s sedimentary rock; younger fossils are found in the upper layers of the earth’s sedimentary rock.
12The fossil record and the geologic time scale provide reference to when and how long organisms have existed on planet Earth.
13The fossil record is the total number of fossils that have been discovered, as well as the information gained from them.
14The geologic time scale is a system of chronological measurement that describes the timing and relationships between events that have occurred throughout Earth's history.
15Turn to an elbow partner and answer the question below Turn to an elbow partner and answer the question below. Discuss how to determine the correct answer.
16With the same elbow partner describe the changes in the fossils you see in each layer and what they tell you about that time period.
17Turn to a different partner Turn to a different partner. Compare layer C to layer F in the diagram below. What evidence do these fossils provide of changes on earth?
18Complete the Using Fossils to Gather Evidence of Once Living Organisms Worksheet
20Evolution is the process through which species change over time.
21Evolution is a scientific theory. A scientific theory is a statement based on observation and experiment. If continued observation and experiment support the statement, it may become widely accepted.
22Activities to demonstrate Evidence and Theory [see resources] D and T SentenceThe Great Fossil Find ActivityXenosmilus ActivityAll three are not needed
23Look at the two images below Look at the two images below. The image on the left shows the skull of a fossil, the Swift Fox (Vulpes velox), compared to the same view of a modern Kit Fox (Vulpes macrotis). With a partner, identify the similarities.
24The Swift Fox (on the left) was alive during the Pleistocene Epoch The Swift Fox (on the left) was alive during the Pleistocene Epoch. Find the Pleistocene Epoch on the Geologic Time Scale diagram to the right.
25If the Swift Fox was alive about 1 million years ago, why is it so similar to the modern Kit Fox?
26Look at these three organisms Look at these three organisms. Each fossil comes from a different time on the Geologic Time Scale. Are they similar? How?
27What can we learn from these two fossil comparisons?
28Living or once living things share common ancestors and fossils provide evidence for common ancestry.Physical characteristics of organisms change over time and fossils provide evidence of change.
29Living or once living things share common ancestors and fossils provide evidence for common ancestry.
30Physical characteristics of organisms change over time and fossils provide evidence of change.
31Evidence to support the Theory of Evolution… Fossils provide evidence of evolution as the previous slides demonstrated.What other evidence might support evolution?
32Similarities in Structure and Development provide evidence for the Theory of Evolution.
33Vestigial Structures are physical structures that were fully developed and functional in an ancestral group of organisms but are reduced and unused in later species.
34Vestigial Structure Examples In the bodies of whales there are small leg bonesThe skeletons of snakes also have traces of leg-like structures that are not used
35Vestigial Structure Examples Vestigial toe in the horse
38Similarities in Development Organisms that appear to be very different as adults are similar during early development.
39Scientists can also tell how closely organisms are related by comparing their genetic material (DNA).
40In the previous slides we have identified the following evidence of evolution: Fossils, Similarities in Structure and Development, and DNA.Which of the these three main types of evidence do you think would best help scientists prove the relationships among the organisms?
41A Cladogram or a Branching Diagram are often used to illustrate common ancestry and evolution. Students do not need to know how to make a cladogram or a branching diagram. Students just need to be able to look at the diagrams and identify common ancestors and species that have the greatest variety.
42Which organisms have fur and mammary glands? Common Ancestor
50With a seat partner, compare and contrast the information Figure 1 will provide to the information Figure 2 will provide.Figure 1Figure 2Figure 1 can be used to identify how long certain fossils appeared on earth; Figure 2 can be used to identify the common ancestor of the organisms shown and common characteristics among organisms. Figure 2 can also identify phyla that are the most closely related to one another.
51Evidence of Evolution Video: https://www.youtube.com/watch?v=lIEoO5KdPvg
52Summarizing Strategy: 3 – 2 – 1 Describe three ways in which scientists support the theory of evolution.Identify two ways in which scientists know the physical characteristics of organisms change over time.Describe why the fossil record is important.