Development of the Biosphere 5.1 Flashcards
In the Beginning…
- strong UV rays
- volcanoes adding gases
- violent storms- lots of lightning
- atmosphere=water vape, methane, Pannonia, CO2, nitrogen, hydrogen.
- NO free Oxygen
Spontaneous generation of life. Real or not real? What theory of life was established from this?
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.”
Urey-Miller Experiment? Aim, Method & Results…
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.
The First cells…
Microspheres trapped inside chemicals that attracted other molecules into its membrane > feeding, growing & replicating copies > sphere splits in 2 > reproduction.
Chemosynthesis?
Cells evolved ability to make own food from environmental chemicals such as CO2 and H2O/
The Archaea?
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
How does photosynthesis work?
Water + Carbon Dioxide —(sunlight)—> Glucose + Oxygen
Photolysis…
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
Cyanobacteria…
bacterial type cells that use chlorophyll to trap light, produce oxygen as waste product.
Stromatolites?
cyanobacteria grew in warm, shallow seas inside stromatolites (fossil). layered columns of cells found in WA.
Oxic world?
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.
Oxic world?
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.
How did genetic variations speed up production of species?
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.
Eukaryotic cells?
Cells with organelles and a nucleus which are built from membranes.
Prokaryotic Cells?
lack a nucleus and organelles but contain a chromosome which contains DNA (bacteria and archaea)
First Multicellular organism?
Ancient stromatolites were built by prokaryotic bacteria were multicellular.
Ediacaran Animals?
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.
Example of a common ediacaran animal?
Dickinsonia
Cambrian event?
Sudden appearance of hard body fossils 545mya
Survival advantages of hard bits?
- 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.
First land plant?
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.
