This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: What evidence of life on Earth before stromatolites do we have? What will be an ideal ... (Read 19 times)

stephzh

  • Hero Member
  • *****
  • Posts: 556
on: Jul 15, 2018
What evidence of life on Earth before stromatolites do we have? What will be an ideal response?

Question 2

What are stromatolites, and why are they important in Earth history? What will be an ideal response?


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

Kdiggy

  • Sr. Member
  • ****
  • Posts: 340
Reply #1 on: Jul 15, 2018
Answer to Question 1

In Greenland, 3.8 billion-year-old rocks contain small carbon spheres that may be organic in origin,
but evidence is not conclusive. Archean and Early Paleoproterozoic rocks contain fossils of singlecelled
bacteria that lack a cell nucleus and reproduced asexually, called prokaryotic cells



Answer to Question 2

Stromatolites are blue-green algae that trap sediment. They are common in some Proterozoic rocks,
but the oldest are in 3.3 to 3.5 billion-year-old rocks. Stromatolites are important because the
atmosphere of the Paleoarchean had no free oxygen, but stromatolites release oxygen as a by-product
of photosynthesis. In the Archean and more so in the Proterozoic, they increased oxygen in Earth's
atmosphere.



stephzh

  • Member
  • Posts: 556
Reply 2 on: Jul 15, 2018
YES! Correct, THANKS for helping me on my review

Alyson.hiatt@yahoo.com

  • Member
  • Posts: 354
Reply 3 on: Yesterday
Great answer, keep it coming :)

« previous next »
 

Did you know?

In 1835 it was discovered that a disease of silkworms known as muscardine could be transferred from one silkworm to another, and was caused by a fungus.

Did you know?

Asthma cases in Americans are about 75% higher today than they were in 1980.

Did you know?

The average human gut is home to perhaps 500 to 1,000 different species of bacteria.

Did you know?

Prostaglandins were first isolated from human semen in Sweden in the 1930s. They were so named because the researcher thought that they came from the prostate gland. In fact, prostaglandins exist and are synthesized in almost every cell of the body.

Did you know?

People who have myopia, or nearsightedness, are not able to see objects at a distance but only up close. It occurs when the cornea is either curved too steeply, the eye is too long, or both. This condition is progressive and worsens with time. More than 100 million people in the United States are nearsighted, but only 20% of those are born with the condition. Diet, eye exercise, drug therapy, and corrective lenses can all help manage nearsightedness.

Life Table Life Table
Earth scientists have devised a scheme to divide the planet’s natural history into distinct time ... Earth scientists have devised a scheme to divide the planet’s natural history into distinct time ...
Layers of Earth Layers of Earth
Early geologists discovered evidence of past glaciations in U-shaped valleys Early geologists discovered evidence of past glaciations in U-shaped valleys
Life in sulfur-rich, anoxic sediments Life in sulfur-rich, anoxic sediments
Life cycle of a typical flowering plant. Life cycle of a typical flowering plant.
Video: Hip Animation

For a complete list of videos, visit our video library