Geologic Time Project Blog 9/29

Most of the major events that occurred in Geologic Time happened later on down the timeline, closer towards modern times. Earlier on, animals, plants and other organisms were evolving. Geologic time is a record of the history of rocks and fossils in the Earth, so scientists are making predictions and hypotheses as to what could’ve occurred during that time.

Each of the eras had a remarkable event that was marked off in Geologic Time. For instance, in the Precambrian era, the Earth was formed and life was just beginning to evolve. Bacteria and fungi came before humans, and oxygen even appeared when the Earth developed an atmosphere. In the Paleozoic era, the end-Permian extinction cut off many invertebrate groups. In the Mesozoic era, scientists believe that an asteroid from space crashed to the Earth and wiped out all dinosaur species. In the Cenozoic era, the ice ages occurred, and at the end of them, the sudden climate change caused many large mammal species like woolly mammoths and sabre-tooth cats to go extinct.

All of these events have been marked in fossils and rocks that scientists have studied. They came up with the Geologic Time Scale, which lead to further theories and predictions about what occurred in Earth’s history.

Backward-Looking

What process did you go through to produce this piece?

When producing this piece, I needed to research my era, the Cenozoic. Some important information that we needed to know was how long the era lasted, what major events occurred during the era, and what sorts of animals, plants and organisms evolved during the time. Once we were finished with data and research, we needed to create an interactive poster about our eras as a group. The poster contained all of the information that we had found.

Inward-Looking

What was especially satisfying to you about either the process or the finished product?

I really thought that seeing our super-tall poster with all of our information on it was very satisfying. I knew that I had worked very hard on my era, and seeing it all exactly how I wanted it was very satisfying to me. Also, getting all of my drawings for the poster done was another really big satisfaction for me.

Outward-Looking

Did you do your work the way other people did theirs? In what ways did you do it differently? In what ways was your work or process similar?

Some people did a flatter poster where it laid on a table and you could see what the landscape looked like. Some kids did pop-outs were if you opened a flap, the information and a picture would pop out. Other kids chose to do the poster like ours, where the eras were split up and each was decorated by that one person.

Forward-Looking

What would you change if you had a chance to do this piece over again?

If I could do this work over again, I would’ve gone to some different websites. After the project was complete, I was browsing, and I found some websites that explained the information better than the ones I had used. Another thing I would’ve done is focused more on my drawings. Some of them were a bit rushed, and I think that I could’ve done better.

Geologic Time 9/22

geologic-time-scale1.jpg by canadiangoldprospector.wordpress.com

Earth’s history, or Geologic Time, is split into four eras. The Precambrian era, the Paleozoic era, the Mesozoic era and the Cenozoic era are the four eras that help geologists understand which time frame a major event or mass extinction happened. 

The Cenozoic era is the present day era, the one we are currently living in. It began 66 million years ago when the Mesozoic era ended and hasn’t ended yet. It is split into two periods, the Tertiary period and the Quaternary period.
The Tertiary period began when the era started and ended 1.8 million years ago. The first monkeys and apes began to appear around the Tertiary period, and grass began to evolve. Flowering shrubs became the most common plants. The Quaternary period started 1.8 million years ago and has not ended. We are currently living in it now. Mammals, insects and flowering plants dominated the land. Humans began to appear. Later on in the period, about 20,000 years ago, the larger mammals like mammoths went extinct. 

In the Tertiary period, the climate was mostly warm. Plants and animals thrived. Plants had a chance to grow now that the dinosaurs were extinct. Grasses evolved and became food for the ancestors of today’s grass-eating mammals. During the Quaternary period, animals had a harder time. The climate shifted around a lot. It began warm, and then the climate bega to cool. Continental glaciers spread over North America and Europe. The ice ages began. Animals dominated the parts of North America that had no ice. About 20,000 years ago, the climate warmed up again, and the ice melted everywhere but Greenland and Antarctica.
During the Cenozoic era, the oceans widened, causing sea animals to thrive. The Himalayas, the Swiss Alps and the Rockies are all mountains ranges that formed during the Cenozoic era. Mammoths, sabre-tooth cats, giant deer and giant land sloths all went extinct. Flowering plants and grass became common.

S&EP: SP2
While we studied the eras and geologic time, I found that a timeline helped me a lot. There was one in the textbook we were using and showed specific dates, organisms and names, both scientific and not. It was helpful to see it all mapped out and to be able to understand something that was portrayed in a way that was difficult to see on different sources. I also liked the timeline because it gave me a lot of information on each of the geologic eras.

XCC: Cause and Effect
There were a lot of cause and effect relationships in Geologic time. For instance, the climate cooled off in the Cenozoic era, causing the effect of an ice age across the world. Dinosaurs went extinct during the Mesozoic era, causing he effect of proliferating plant growth in the Cenozoic era. The cause and effect we can observe from the past can help us make predictions of what will happen in the present/future. We can study the climate and predict if ice ages or heat waves will be coming. We can predict what will happen in black rhinos go extinct, and then we can do something about it. We can stop extinction, and we can stop global warming. Science and cause and effect can help us prepare for what could be coming in the future.

Rock Cycle 9/12/18

Rock Cycle by L.E.

The Rock Cycle

Geology is the study of the structure of the planet Earth and the forces that make and shape this planet. Geology literally means “study of the Earth”. “Geo” means “Earth” and “logos” means “study of”. 

If things like volcanoes and earthquakes shape mountains and monuments in the present day, we can estimate what could have happened in the past. Rocks that are around today could have been around in the past.

Geologists classify rocks into three main groups: igneous, sedimentary, and metamorphic. 

Igneous rocks are made of fire. They form when molten material from the Earth’s core hardens and cools inside or outside of the Earth’s crust. Igneous rocks can look entirely different from each other based on their rate of cooling or where they cooled. If an igneous rock hardened closer to the Earth’s core than one that hardened on or closer to the surface.

Sedimentary rocks are made through settling. They are made from sediments that have been deposited and then forced together to create a rock. Sedimentary rocks can have sand, dirt, fossils, and shells in them because all of these things are carried through sediments.

Metamorphic rocks are made through change. They are formed when a rock that ALREADY EXISTS is changed by immense amounts of intense heat and pressure or a chemical reaction. 

The rock cycle is a series of processes on and beneath the Earth’s surface that transforms one type of rock to another and back again over time. The rock cycle is the Earth’s way of changing rocks.

Relative and Absolute Age:

The Geologic Time Scale is a record of Earth’s life forms and geologic events in Earth’s history. 

We do not talk calendars when we talk about the Earth’s geologic history because Earth is 4.6 billion years old and calendars are 2,018 years old. 

Geologists use both relative and absolute age depending on what organism it is. 

Relative age is the age of a rock or fossil compared to the rocks or fossils near or around it. Absolute age is the age of a rock since it was first formed. Everyone and everything has a relative and absolute age. 

The law of superposition states that in a horizontal sedimentary rock layer, the oldest layer is at the bottom. The youngest, or most recent, is at the top. The law of superposition helps us determine the relative age in a sedimentary rock layer. 

Determining Relative age:

Cross-cutting principle: when something cuts across a body of rock, the ‘something’ is ALWAYS younger than the rock it cuts across. 

Clues from igneous rock:

Magma that hardens on the surface of the Earth is called an extrusion. An extrusion is always younger than the rocks/soil around or near them. Magma that cools and hardens below the Earth’s surface is called an intrusion. Intrusions are always younger than the soil around them. This is because the rocks and soil were there before the magma cooled and made the igneous rocks. 

Clues from faults:

Faults are always younger than the rocks/plates they cut across. 

Imagine a hole. The hole is younger than the area of soil, grass and rocks around it. You can’t have a hole first and then the rocks, grass and soil. The hole or fault is always going to be younger. 

Index fossils help geologists match rock layers and help to determine the relative ages of rocks in which they occur. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed/lived only briefly. 

S&EP: SP2

I used models to visually explain how geologists use fossils to estimate relative and absolute age. We used a fossil simulation to match the layers of fossils and help us determine which creatures existed when. We also used a Task simulation on goformative that helped us order the fossils from the oldest on the bottom to the most recent on the top. 

Models are useful in situations like these because they can help you grasp better understanding of the tasks at hand and can help you learn things, like how to estimate relative and absolute age, how to order fossils based on age, and how to make inferences based on your discoveries. 

XCC: Patterns

This image displays an example of a pattern we’ve used in class. This is a screenshot of the fossil simulation that we used to help us. The oldest layer of fossils is on the bottom. 

You are able to see where the same types of organisms line up with each other. This is a pattern, because an organism cannot go extinct and then randomly appear again. Some may live for longer than others, like the fossils that line up in every segment, but some might only live for a little while, like the fossils that accumulate in only one or two of the segments. 

Some organisms can live before others do and live long after some go extinct. Some organisms are able to survive longer than others, or other animals might’ve preyed on the smaller ones, causing them to go extinct before the more carnivorous ones.