Development of the Biosphere 5.1

Question 1

In the Beginning…

Answer 1

• strong UV rays
• volcanoes adding gases
• violent storms- lots of lightning
• atmosphere=water vape, methane, Pannonia, CO2, nitrogen, hydrogen.
• NO free Oxygen

Question 2

Spontaneous generation of life. Real or not real? What theory of life was established from this?

Answer 2

Not real. Proven wrong by Louis Pasteur that air cannot begin life: only airborne spores can.

• open flask vs goose neck flask experiment.
• Cell theory of life established as principle “All cells come from pre-existing cells.”

Question 3

Urey-Miller Experiment? Aim, Method & Results…

Answer 3

Aim: To test if conditions of primitive earth could produce life starting molecules.

Method: Simulate conditions of primitive earth:

• electric spark (lighting)
• water (oceans)
• gases(atmosphere)

Results: supports aim as shows life-forming chemicals could have been produced naturally-through production of sugars and amino acids.

Question 4

The First cells…

Answer 4

Microspheres trapped inside chemicals that attracted other molecules into its membrane > feeding, growing & replicating copies > sphere splits in 2 > reproduction.

Question 5

Chemosynthesis?

Answer 5

Cells evolved ability to make own food from environmental chemicals such as CO2 and H2O/

Question 6

The Archaea?

Answer 6

A varied group of single-celled, anaerobic-like organisms living in extreme conditions which get their energy from chemosynthesis (inorganic chemicals):

• acidic, volcanic springs
• deep ocean: black smokers

Question 7

How does photosynthesis work?

Answer 7

Water + Carbon Dioxide —(sunlight)—> Glucose + Oxygen

Question 8

Photolysis…

Answer 8

Is the splitting of water molecules by light.

• Chlorophyll absorbs light energy to split H2O molecules.
• Oxygen released from this changed atmosphere > evolution possible
• Hydrogen combined with CO2 to form glucose

Question 9

Cyanobacteria…

Answer 9

bacterial type cells that use chlorophyll to trap light, produce oxygen as waste product.

Question 10

Stromatolites?

Answer 10

cyanobacteria grew in warm, shallow seas inside stromatolites (fossil). layered columns of cells found in WA.

Question 11

Oxic world?

Answer 11

use to be anoxic meaning all the oxygen was trapped water and oxygen. when cyanobacteria began modern style photosynthesis in stromatolites they produced oxygen as a by-product> changing the earths atmosphere.

Question 12

Oxic world?

Answer 12

use to be anoxic meaning all the oxygen was trapped water and oxygen. when cyanobacteria began modern style photosynthesis in stromatolites they produced oxygen as a by-product> changing the earths atmosphere.

Question 13

How did genetic variations speed up production of species?

Answer 13

When 1bya cells began conjugation where cells swap DNA fragments in a sexual fertilisation. Happens by a tub passing fragments of DNA through the 2 different cells.

Question 14

Eukaryotic cells?

Answer 14

Cells with organelles and a nucleus which are built from membranes.

Question 15

Prokaryotic Cells?

Answer 15

lack a nucleus and organelles but contain a chromosome which contains DNA (bacteria and archaea)

Question 16

First Multicellular organism?

Answer 16

Ancient stromatolites were built by prokaryotic bacteria were multicellular.

Question 17

Ediacaran Animals?

Answer 17

Soft bodied organisms that were before the Cambrian event (WA)

• no shells, teeth or skeletons so they grazed sea floor.
• lack of fossils due to no hard body parts.

Question 18

Example of a common ediacaran animal?

Answer 18

Dickinsonia

Question 19

Cambrian event?

Answer 19

Sudden appearance of hard body fossils 545mya

Question 20

Survival advantages of hard bits?

Answer 20

• shells & exoskeletons g=protect against predators
• Hard bodied protect from UV
• Skeletons support body> can grow larger
• provide solid point of attachment for muscles> powerful movements
• Evolution of predation> fossils discovered with chunks bitten out of them.

Question 21

First land plant?

Answer 21

Spores found in swampy wetlands and tropics.
Cooksonia:
-covered in waxy cuticle to prevent water loss
-Had small pores to let gases get in & out.