Term
| What are the four steps in the origins of life? |
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Definition
-formation of simple organic molecules
-formation of complex organic molecules
-formation of self replicating molecules
-compartmentalisation of first cell |
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Term
| What happened in the formation of simple organic molecules step? |
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Definition
| Abiotic synthesis of small organic molecules |
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Term
| What are examples of the simple organic molecules that were formed? |
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Definition
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Term
| What happened in the formation of complex organic molecules step? |
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Definition
| The joining of monomers into polymers |
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Term
| What are examples of the complex organic molecules that were formed in the Miller-Urey experiment? |
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Definition
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Term
| What happened in the formation of self replicating molecules step? |
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Definition
| The formation of RNA and DNA |
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Term
| What happened in the compartmentalisation of first cell step? |
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Definition
| The packaging of all molecules formed into protobionts |
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Term
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Definition
| Droplets with membranes that maintain an internal chemistry different from that of their surroundings |
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Term
| Which experiment showed how simple organic molecules were formed? |
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Definition
| The Miller-Urey experiment |
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Term
| What is the Miller-Urey experiment? |
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Definition
| A recreation of early earth atmosphere and addition of electrical discharge or UV light |
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Term
| What did the Miller-Urey experiment show? |
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Definition
| Formation of complex molecules, sugars, nucleic acids and amino acids |
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Term
| What did the Miller-Urey experiment show that was confusing? |
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Definition
| Compounds that would have prevented the formation of polymers were also formed in high concentrations |
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Term
| What supports the theory that deep sea vents may have been the origin of life? |
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Definition
| They are regions rich in inorganic sulfur and iron compounds that are important in ATP synthesis by present day organisms |
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Term
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Definition
| The theory that life originated from microorganisms or chemicals that came from space |
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Term
| What is special about the Murchison meteorite? |
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Definition
| It contained water and organic molecules, such as amino acids |
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Term
| What is the PAH hypothesis? |
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Definition
| Polycyclic aromatic hydrocarbons have both hydrophilic and hydrophobic parts so organise in stacks |
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Term
| How is the PAH hypothesis related to the formation of complex organic molecules? |
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Definition
| Smaller molecules attach to PAH rings and this acts as a scaffold. |
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Term
| What is an example of how PAH stacks help to form complex molecules? |
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Definition
| Bases attach to the PAH stack and ribose molecules attach and form a chain. |
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Term
| What is the polynucleotide-polypeptide dilemma? |
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Definition
| DNA needs proteins to self replicate but proteins required DNA to evolve |
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Term
| What did the Miller-Urey experiment show happened to lipids and proteins when heated? |
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Definition
| They formed microspheres spontaneously |
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Term
| What does the spontaneous formation of microspheres suggest? |
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Definition
| The first cells may have been formed by the encapsulation of protogenomes |
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Term
| How is RNA different to DNA that makes it more likely to have evolved first? |
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Definition
-Simpler - doesn't require an enzyme to unzip strands
-Can take on different structures - can act as genes and enzymes |
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Term
| What are the three types of ribozyme activities first discovered? |
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Definition
-cleavage of other RNAs
-synthesis of peptide bonds
-self cleavage |
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Term
| What are the three types of ribozyme activities discovered later? |
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Definition
-synthesis of RNA molecules
-synthesis of ribonucleotides
-transfer of an amino acid bound to a peptide to second amino acid to form a dipeptide |
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Term
| What are two features of the protobionts? |
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Definition
Simple reproduction
Simple metabolism |
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Term
| Fill in the blanks for protobiont metabolism[image] |
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Definition
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Term
| What is the first evidence of prokaryotes? |
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Definition
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Term
| How far do stromatolites date back? |
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Definition
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Term
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Definition
| Rock like structures composed of many layers of bacteria and sediment |
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Term
| Where did photosynthesis evolve? |
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Definition
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Term
| Was photosythesis the same when it evolved as it is now? |
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Definition
| No, it started as a metabolic version that didn't split water but did release oxygen |
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Term
| Where was the majority of oxygen on earth when photosynthesis first evolved? |
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Definition
| Dissolved in water, which saturated the sea |
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Term
| What happened after the oxygen saturated the sea? |
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Definition
| It reacted with dissolved iron to form iron ocxide deposits |
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Term
| What happened when oxygen levels started to rise due to photosynthesis? |
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Definition
| Prokaryotic groups were killed so aerobic respiration evolved |
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Term
| Why were prokaryotic groups killed when oxygen levels rose? |
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Definition
| Oxygen attacks chemical bonds and can inhibit enzymes and damage cells |
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Term
| In which forms can oxygen damage cells? |
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Definition
| O2, H2O2 or other compounds |
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Term
| Fill in the blanks about energy levels[image] |
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Definition
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Term
| What is suggested that is the cause of the formation of eukaryotic cells? |
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Definition
| Prokaryotic cells were engulfed and formed a symbiotic relationship |
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Term
| How does the cell membrane allow energy to be generated? |
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Definition
| It allows metabolite enzymes to be spatially arranged in a sequence such as for electron transport |
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Term
| What is Mixotricha paradoxa and how is it an example of complex symbiosis? |
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Definition
| A protist living in gut of termites living in symbiosis with three bacteria, two provide movement and one digests wood. |
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Term
| What is Elysia chlorotica and how is it an example of a genetic chimera (hybrid)? |
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Definition
| A slug that eats algae and contains palstid DNA and fragments of chloroplast genes |
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Term
| What are the advantages of being a multicellular organism (metazoa)? |
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Definition
-Further specialisation is possible
-Cells co-operate to give rise to a functional organism |
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Term
| What was the first animal to evolve? |
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Definition
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Term
| What are the two most distinct body forms of Ediacaran fauna? |
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Definition
-radical symetry
-fronds and tube like forms |
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Term
| What does the snowball earth hypothesis suggest? |
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Definition
| -That there were long periods where oceans were frozen |
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Term
| How may life have survived when the oceans were frozen? |
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Definition
| By living near deep sea thermal vents and having accelerated chemistry |
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Term
| What was the Cambrian explosion? |
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Definition
| The evolution of bilaterals |
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Term
| What first colonised land? |
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Definition
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Term
| What two life forms evolved and in which order? |
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Definition
-Vascular plants
-Predatory insects |
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Term
| What four adaptations allowed vertebrates to live on land? |
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Definition
-developed ability to breathe air
-developed limbs
-limbs were specialised
-developed amniotic egg |
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Term
| What were the first lung like organs to evolve? |
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Definition
| Air sacks in primitive bony fish |
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Term
| What did the air sacks in primitive bony fish become in modern fish? |
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Definition
Swim bladders in bony fish
Lungs in lung fish |
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Term
| In which animal did the first limbs evolve? |
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Definition
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Term
| How did the first limbs evolve? |
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Definition
Lobe finned fish - had small bones in fins that allowed them to pull out of the water and support their weight
Early amphibians - lost fin rays and only had bones in their limbs |
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Term
| What was the first tetrapod fish? |
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Definition
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Term
| How did Ichthyostega live? |
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Definition
| Mostly in the water, using its back legs for paddling |
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Term
| What is special about Ichthyostega? |
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Definition
| All land creatures with backbones can trace ancestry to them |
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Term
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Definition
| After the Cretaceous-Tertiary (K/T) event |
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Term
| What happened in the Cretaceous-Tertiary (K/T) event? |
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Definition
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Term
Complete the diagram of defining evolutionary moments for each vertibrate
[image] |
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Definition
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