Geological Timescale

Question 1

What is this

Answer 1

It’s helps us divide vast periods of time into manageable time frame

Question 2

What have geologist divided earths history into

Answer 2

Eras
Periods
Epochs

Question 3

What are eons, periods, eras

Answer 3

Eons - longest time period and are hundred of millions years long

Eras -smaller time periods that eons are divided into

Periods -eras are made up of diff periods of different time length

Question 4

What is the Cambrian explosion

Answer 4

Part of the palaeozoic era

scientists believe that the oxygen levels rose in the atmosphere owing o to the emissions from the many photosynthesising cyanobacteria and algae in the oceans. The oxygen was available for growth of more complex body structures

The environment became warmer and more conducive to creating many habitable ecosystems. Sea levels rose and flooded
OSIClow lying areas and created warm shallow waters that were ideal for the evolution of the more complex life forms.

modern phyla of animals had developed in the seas, including insects, amphibians, plants, fishes, and reptiles.

Some of the animals in the Cambrian period included hard-bodied animals- this was an important innovation in evolution.
The hard bodies provided a good defence against the fierce predators of the time and a firm supporting framework for a bigger body size.

Question 5

Explain what is the sixth extinction

And give examples of what is causing it

Answer 5

Many scientists believe that we are in the middle of a mass extinction. This extinction is caused by human activities that are speeding up the rate at which species are dying out. Human impact affects the environment in the following ways:

1. Overpopulation of the human species.
2. Habitat destruction.
3. Pollution.
4. Global warming.
5. Declining biodiversity.
6. Unsustainable hunting practices.

Question 6

What caused mass extinction

Answer 6

meteor impacts, 
volcanic activity, 
sea-level changes, 
oxygen depletion, 
global cooling, 
changes in ocean chemistry, 
and ice ages with glaciers.

Question 7

How much of log of earth went extinct

Answer 7

More than 90 percent of all organisms that have ever lived on Earth are extinct.