Fossils
Chapter 16 Lesson 1
Pages 564 - 572
Vocabulary
• Fossil – the preserved remains or evidence of ancient living things
• Catastrophism – the idea that condition...
Evidence of the Distant Past
• Just like old photos, fossils provide us with
clues about Earth’s past
• Fossils are the pr...
Catastrophism
• Many fossils represent plants and animals that are extinct
• In the past many scientists believed that a s...
Catastrophism
• Scientists eventually disagreed with
catastrophism because Earth’s history is full of
violent events
• Mos...
Uniformitarianism
• In the 1700s, James Hutton rejected the idea of
catastrophism
• Hutton thought that the processes resp...
Uniformitarianism
• Hutton’s ideas were eventually included in a
principle called uniformitarianism.
– The principle of un...
Uniformitarianism
• Today, uniformitarianism is the basis for understanding
Earth’s past
• But scientists also know that c...
Fossil Formation
• Not all dead organisms become fossils. More
than likely, you will not become a fossil.
• Fossils form o...
Conditions for Fossil Formation
• Most plants and animals are eaten or decay when they die, leaving
no trace that they eve...
Fossils Come in All Sizes
• Many of the fossils we think of are large dinosaur fossils.
• However, not all fossils are lar...
Types of Preservation
• Fossil are preserved in many different ways:
– Preserved Remains
– Carbon Films
– Mineral Replacem...
Preserved Remains
• Sometimes the actual remains of organisms are
preserved as fossils
• For this to happen, an organism m...
Carbon Films
• Sometimes when an organism is buried, exposure to
heat and pressure forces gases and liquids out of the
org...
Mineral Replacement
• Replicas, or copies, of organisms can form
from minerals in groundwater.
• They fill in the pore spa...
Molds
• Sometimes all that remains of an organism is its fossilized imprint or
impression.
• A mold is the impression in a...
Casts
• Sometimes, after a mold forms, it is filled with
more sediment,.
• A cast is a fossil copy of an organism made whe...
Trace Fossils
• Some animals leaves fossilized traces of their movement or activity
• A trace fossil is the preserved evid...
Ancient Environments
• Scientists who study fossils are called paleontologists
• Paleontologists use the principle of unif...
Shallow Seas
• Today, Earth’s continents are mostly above sea level.
• But, sea level has risen, flooding Earth’s continen...
Past Climates
• Evidence indicates that Earth's present-day climate is
warming.
• Fossils show that Earth's climate has wa...
Past Climates
• Huge sheets of ice called glaciers spread over
parts of N. America, Europe, and Asia.
• Fossils suggest th...
Chapter 16.1: Fossils
Upcoming SlideShare
Loading in...5
×

Chapter 16.1: Fossils

531

Published on

Grade 8 Integrated Science Chapter 16 Lesson 1 on fossils. This lesson gives detail about fossil, how they form, and the different types. The purpose of this lesson is for students to understand fossil and how they give us a record of our planet's past. Students should know the different types of fossils by the end of the lesson.

Published in: Education
0 Comments
3 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
531
On Slideshare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
31
Comments
0
Likes
3
Embeds 0
No embeds

No notes for slide

Chapter 16.1: Fossils

  1. 1. Fossils Chapter 16 Lesson 1 Pages 564 - 572
  2. 2. Vocabulary • Fossil – the preserved remains or evidence of ancient living things • Catastrophism – the idea that conditions and organisms on Earth change in quick, violent events • Uniformitarianism – a principle that states that geologic processes that occur today are similar to those that have occurred in the past • Carbon Film – the fossilized carbon outline of an organism or part of an organism • Mold – the impression in a rock left by an ancient organism • Cast – a fossil copy of an organism made when a mold of the organism is filled with sediment of mineral deposits • Trace Fossil – the preserved evidence of the activity of an organism • Paleontologist – scientists who study fossils
  3. 3. Evidence of the Distant Past • Just like old photos, fossils provide us with clues about Earth’s past • Fossils are the preserved remain or evidence of ancient living things
  4. 4. Catastrophism • Many fossils represent plants and animals that are extinct • In the past many scientists believed that a single, sudden, catastrophic disaster killed the organisms that become fossil • Catastrophism is the idea that conditions and organisms on Earth change in quick, violent events – These include large volcanic eruptions and widespread flooding
  5. 5. Catastrophism • Scientists eventually disagreed with catastrophism because Earth’s history is full of violent events • Most people who supported catastrophism thought that Earth was only a few thousand years old
  6. 6. Uniformitarianism • In the 1700s, James Hutton rejected the idea of catastrophism • Hutton thought that the processes responsible for changing the landscape could also shape Earth’s surface – For example, he thought that erosion caused by streams could also wear down mountains – He realized that these processes would take a long time and proposed that Earth was much older than a few thousand years
  7. 7. Uniformitarianism • Hutton’s ideas were eventually included in a principle called uniformitarianism. – The principle of uniformitarianism states that geological processes that occur today are similar to those that have occurred in the past – According to this view, Earth’s surface is constantly being reshaped in a steady, uniform manner
  8. 8. Uniformitarianism • Today, uniformitarianism is the basis for understanding Earth’s past • But scientists also know that catastrophic event do sometimes occur – Huge volcanic eruptions and giant meteorite impacts can change Earth’s surface quickly and can be explained by natural processes
  9. 9. Fossil Formation • Not all dead organisms become fossils. More than likely, you will not become a fossil. • Fossils form only under certain conditions.
  10. 10. Conditions for Fossil Formation • Most plants and animals are eaten or decay when they die, leaving no trace that they ever lived – Consider an apple. More than likely an apple will decay into a soft lump and be decomposed by bacteria and insects • Some conditions increase the chances that a fossil will form. 1. If the organism has hard parts, such as shells, teeth, or bones 2. If the organism is buried quickly after it dies. • This way the layers of sand and mud slow or stop decay
  11. 11. Fossils Come in All Sizes • Many of the fossils we think of are large dinosaur fossils. • However, not all fossils are large. • Microfossils are tiny fossils each about the size of a speck of dust. – Details of microfossils can be seen only under a microscope
  12. 12. Types of Preservation • Fossil are preserved in many different ways: – Preserved Remains – Carbon Films – Mineral Replacement – Molds – Casts – Trace Fossils
  13. 13. Preserved Remains • Sometimes the actual remains of organisms are preserved as fossils • For this to happen, an organism must be completely enclosed in some material over a long period of time. – This would prevent it from being exposed to air or bacteria – Generally this fossils are less than 10,000 years old. However insects preserved in amber can be millions of years old.
  14. 14. Carbon Films • Sometimes when an organism is buried, exposure to heat and pressure forces gases and liquids out of the organism’s tissues. • This leaves only the carbon behind • A carbon film is the fossilized carbon outline of an organism or part of an organism
  15. 15. Mineral Replacement • Replicas, or copies, of organisms can form from minerals in groundwater. • They fill in the pore spaces or replace the tissues of dead organisms • Petrified wood is an example
  16. 16. Molds • Sometimes all that remains of an organism is its fossilized imprint or impression. • A mold is the impression in a rock left by an ancient organism 1. First, sediment must harden around a buried organism 2. As the organism decays over time an impression of its shape remains in the sediment 3. Eventually the sediment turns into rock
  17. 17. Casts • Sometimes, after a mold forms, it is filled with more sediment,. • A cast is a fossil copy of an organism made when a mold of the organism is filled with sediment or mineral deposits. Mold Cast
  18. 18. Trace Fossils • Some animals leaves fossilized traces of their movement or activity • A trace fossil is the preserved evidence of the activity of an organism • These include – Tracks – Footprints – Nest – Droppings • These fossils help scientists learn about characteristics and behaviors of animals – They can reveal clues about an organism’s size, speed, and whether they traveled alone or in groups
  19. 19. Ancient Environments • Scientists who study fossils are called paleontologists • Paleontologists use the principle of uniformitarianism to learn about ancient organisms and their environment • They often compare fossils of ancient organisms to organisms living today – For example, trilobite fossil and horseshoe crabs look alike – Horseshoe crabs today live in shallow water on the ocean floor – Partly because trilobite fossils look so much like horseshoe crabs, paleontologists infer that trilobites also lived in shallow ocean waters
  20. 20. Shallow Seas • Today, Earth’s continents are mostly above sea level. • But, sea level has risen, flooding Earth’s continents, many times in the past • For example, a shallow ocean covered much of North America 450 million years ago. • Fossils of organisms that lived in that shallow ocean help scientists reconstruct what the seafloor looked like at that time.
  21. 21. Past Climates • Evidence indicates that Earth's present-day climate is warming. • Fossils show that Earth's climate has warmed and cooled many times in the past • Plant fossils are especially good indicators of climate change • For example, fossils of ferns and other tropical plants dating to the time of the dinosaurs reveal that Earth was very warm 100 million years ago • Tropical forests and swamps covered much of the land • Millions of year later, the swamps and forests were gone, but coarse grasses grew in their place
  22. 22. Past Climates • Huge sheets of ice called glaciers spread over parts of N. America, Europe, and Asia. • Fossils suggest that some species that lived during this time, such as the woolly mammoth were able to survive in the colder climate
  1. Gostou de algum slide específico?

    Recortar slides é uma maneira fácil de colecionar informações para acessar mais tarde.

×