history of life Flashcards
name the five kingdoms
bacteria ,protista, fungi, plantae and animalia
the 4 questions scientists tried to work out
- did this diverse range of living organisms develope on earth at the same time or did they develope in a sequence
- if they developed in a sequence ,when was this , and how did it take place
- if they develpoed in a sequence what was the sequence ? was it kingdom by kingdom
- what was the caurses of diversification
what dis scientists think of earth between 4-6 billion years ago
they thought that there was little to no oxygen on primitive earth
how did the absence of oxygen affect the earth
the absence of oxygen allowed the gasses present in the atmosphere at the time to form organic molecules such as fatty acids and protein which is the building blocks of living organisms
what is the first formed life forms
it is the prokaryotes ,like some present day bacteria
when di the prokaryotes develop
it developed about 3.5 billion years ago
what does anaerobic mean
it means that the prokaryotes did not require oxygen for their activities . they could release energy from their food supply without the use of oxygen
when did different bacteria’s begin to develop
between 3.5 and 2.5 billion years ago
name one of the bacteria that began to develop
blue -green bacteria (cyanobacteria )
what is the function of blue -green bacteria
the function is to manufacture food by the process of photosynthesis , during photosynthesis carbon dioxide is taken in and oxygen is released
what is aerobic
living organisms that depend on oxygen to release energy from their food
when did aerobic organisms develop
they developed as more oxygen was collected in earths atmosphere
what do scientists believe about the absence of oxygen
they believe that it led to the creation of life itself
what do scientists believe about the increase of oxygen
they believe that the increase of oxygen levels led to an increase in the diversity of living organisms
define ice age
ice age i long periods of time when the earth experienced extremely cold whether
what are the four ice ages that was identified since the time earth was formed
700 million years ago
320 million years ago
286 million years ago
the current ice age , which began slightly less than 3 million years ago
what are glaciers
large sheets of ice
what is glaciantion
the process of the formation of large sheets of ice
when are glaciers formed
during the ice age
what caused large scale of extinction of life forms
glaciation and the sudden cooling that it brought about
what is continental drift
the changing position if the continents
plate tectonics
upward movement of continental blocks