1. fossil evidence
DESCRIPTION
1. Fossil Evidence. Prediction : If life has changed over time then we should find evidence of organisms different from those found today. Fossils are the remains of plants or animals that lived a long time ago or the evidence of them. Hard parts of the organism are replaced by minerals. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/1.jpg)
1. Fossil Evidence
• Fossils are the remains of plants or animals that lived a long time ago or the evidence of them.
• Hard parts of the organism are replaced by minerals.
Prediction: If life has changed over time then we should find evidence of organisms different from those found today.
![Page 2: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/2.jpg)
shells leaves and seeds
bones and teeth
tree trunks and branches
fossilized footprints and burrows
fossilized animal droppings
![Page 3: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/3.jpg)
RELATIVE DATING
YOUNGEST ROCK LAYER
OLDEST ROCK LAYER
ALLOWS ONE FOSSIL TO BE COMPARED TO ANOTHER…FOR EXAMPLE—THE SHELL IS OLDER THAN THE HORSE, BUT YOUNGER THAN THE FISH. WE DON’T KNOW THE EXACT AGE, JUST THE RELATIVE AGE
TOP
BOTTOM
Sedimentary Rock is formed in layers - the older beds are on the bottom, and the younger beds are on the top.
![Page 4: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/4.jpg)
Radiometric Dating• Radioactive Decay: Naturally-occurring
radioactive materials break down into other materials at known rates.
• Many radioactive elements can be used as geologic clocks.
• Time can be estimated by measuring the amount of radioactive element in a sample.
• Half Life = Amount of time it takes for half of the radioactive element to decay
Uranium 235 Half life = 704 million yearsLead 207
Carbon 14 Nitrogen 14 Half life = 5730 years
![Page 5: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/5.jpg)
= Carbon 14(radioactive)
= Nitrogen 14 (stable)
![Page 6: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/6.jpg)
= Carbon 14(radioactive)
= Nitrogen 14 (stable)
After an organism dies, the C14 begins to decay into N14
![Page 7: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/7.jpg)
= Carbon 14(radioactive)
= Nitrogen 14 (stable)
After an organism dies, the C14 begins to decay into N14
![Page 8: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/8.jpg)
= Carbon 14(radioactive)
= Nitrogen 14 (stable)
After an organism dies, the C14 begins to decay into N14
![Page 9: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/9.jpg)
= Carbon 14(radioactive)
= Nitrogen 14 (stable)
This decay happens at a constant rate– in 5730 years HALF of the C14 will have decayed into N14
![Page 10: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/10.jpg)
= Carbon 14(radioactive)
= Nitrogen 14 (stable)
SO, AFTER 1 HALF LIFE—50% REMAINS
![Page 11: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/11.jpg)
= Carbon 14(radioactive)
= Nitrogen 14 (stable)
THE DECAY CONTINUES--
![Page 12: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/12.jpg)
= Carbon 14(radioactive)
= Nitrogen 14 (stable)
AFTER A 2ND HALF LIFE-THERE IS 25% REMAINING (50%25%)
![Page 13: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/13.jpg)
= Carbon 14(radioactive)
= Nitrogen 14 (stable)
AFTER A 3RD HALF LIFE-THERE IS 12.5% REMAINING (25%12.5%)
![Page 14: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/14.jpg)
Decay• 100%50% (1 half life)• 50%25% (2 half lives)• 25%12.5% (3 half lives)• 12.5%6.25% (4 half lives)• 6.25%3.125% (5 half lives)
Challenge Question: A bone is found to have 25% of its carbon-14 remaining. How old is it estimated to be?
![Page 15: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/15.jpg)
2. Homologous structures
• Similar anatomical features that originated in a shared ancestor.
Prediction: if organisms shared common ancestors then we should find evidence of similar structures.
If time, explore the Zoo of You
![Page 16: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/16.jpg)
3. Vestigial structures
• Structures that are useless to an organism but are similar to functional structures of related organisms or ancestors
Prediction: If new species develop from previously existing species then we should find evidence of features that are no longer used today, but were important in ancestors
![Page 17: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/17.jpg)
4. Embryology
• The study of the early stages of development of an organism (inside the womb or inside the egg)
Prediction: If organisms shared common ancestors then we should find evidence that the embryologic structures develop in similar patterns.
If time, play Guess the Embryo
![Page 18: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/18.jpg)
5. Comparing DNA and protein sequencesPrediction: If organisms shared common ancestors then we should find evidence of similar DNA sequences being used to build similar proteins. The more closely related two species are, the more similar their DNA.
![Page 19: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/19.jpg)
1
9
14
18
21
Hypothesized relationship based on number of amino acid differences in cytochrome c
![Page 20: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/20.jpg)
Family Trees (Phylogenetic Trees)• Are based on evidence, such as
homologous structures or DNA/proteins • Provide hypotheses about evolutionary
relationships: –how long since two species shared a
common ancestor (length of line)–How closely related two organisms are
(branching from common ancestor)
![Page 21: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/21.jpg)
RHESUS MONKEY
KANGAROO
BULLFROG
TUNA
LAMPREY
TURTLE
Phylogenetic tree based on number of cytochrome c differences
![Page 22: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/22.jpg)
1) WHICH 2 ORGANISMS SHOW THE CLOSEST RELATIONSHIP?
Human and Monkey- shortest branches
2) WHICH 2 ORGANISMS’ COMMON ANCESTOR LIVED THE LONGEST AGO?Tuna and Lamprey- longest lines
![Page 23: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/23.jpg)
3) WHICH TWO ORGANISMS’ ANCESTOR LIVED MOST RECENTLY?
4) IF YOU DIDN’T KNOW WHAT KIND OF ANIMAL A LAMPREY IS, BASED ON THE TREE-WHAT KIND OF ANIMAL WOULD YOU PREDICT IT IS?Similar to a fish because it has a common ancestor with Tuna
![Page 24: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/24.jpg)
5) COMPARE THE HUMAN-MONKEY RELATIONSHIP WITH THE HUMAN KANGAROO RELATIONSHIP.Human- monkey have more in common because of closer branches.Human- kangaroo have a common ancestor but less related because of longer lines.
6) WHY IS THE KANGAROO IN THE SAME GROUP AS THE HUMAN AND MONKEY-EVEN THOUGH THEY AREN’T AS CLOSELY RELATED?Common ancestor (both are mammals)
![Page 25: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/25.jpg)
• Which pair of species has the fewest differences in their amino acid sequences for myoglobin (a protein)?
Green sea turtle
Logger head turtle
Map turtle
American alligator
Lace monitor lizard
![Page 26: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/26.jpg)
• How does the relationship between green sea turtles and loggerhead turtles compare to the relationship between alligators and monitor lizards?
Green sea turtle
Logger head turtle
Map turtle
American alligator
Lace monitor lizard
Turtles closer related because shorter branches
Alligator and lizard have common ancestor but less related
![Page 27: 1. Fossil Evidence](https://reader036.vdocuments.site/reader036/viewer/2022081422/568164d9550346895dd71fd6/html5/thumbnails/27.jpg)
Sketch a Phylogenetic Tree• A tiger and lion share have 5 differences in their
amino acid sequences for the protein Hemoglobin B. They share a common ancestor, which was cat-like.
• A hyena and a wolf have 18 differences in their amino acid sequences for Hemoglobin B. They share a common ancestor that was dog-like.
• Both cat-like creatures and dog-like creatures share a common ancestor (mammals with paws).
Draw a phylogenetic tree that illustrates this data. Be sure you pay attention to the distances that animals are from their common ancestors.