Topic 8- The tree of life

Question 1

Fossil

Answer 1

Perserved remnant or impression of an organism that lived in the past

Question 2

Stromatolite

Answer 2

Layered rock that results from the activities of photosynthetic prokaryotes that bind thin films of sediment together.

Question 3

Polymerisation

Answer 3

Can bind to other carbon atoms

Question 4

How did life originate on earth?- Steps for organic molecules to protocells

Answer 4

1. The abiotic synthesis of small organic molecules (monomers: amino acids, nitrogenous bases…)
2. The polymerization of small molecules into macromolecules (polymers: proteins, nucleic acids…)
3. The packaging of these molecules into protocells (precursors of cells, with only some components)
4. The origin of inheritance through the transmission of self-replicating molecules

Question 5

Protocell

Answer 5

Protocells droplets with membranes (ex. bilayer of fatty acids) that maintained an internal chemistry different from that of the environment.

Question 6

Self-replication

Answer 6

Proteins (e.g. enzymes) are synthesized from genetic information encoded in DNA and RNA
DNA and RNA are synthesized and replicated by the cell machinery through enzymatic reactions

Question 7

Ribozymes

Answer 7

RNA molecules can also be catalysts and function as enzymes

Question 8

“RNA word”

Answer 8

The first cells were likely encoding the genetic information within RNA

Question 9

What is the Tree of Life

Answer 9

-The first cells were likely encoding the genetic information within RNA.
-Similarities in morphology, anatomy or genetic sequences can be used to group species together

Question 10

Faunal suceession

Answer 10

Specific vertical sequence of fossilized flora and fauna that can be identified reliably over wide horizontal distances.

Question 11

Radiometric dating

Answer 11

Uses changes in the isotope composition of an organism during its transition into a fossil

Question 12

Radiometric dating- At the time of the organism’s death

Answer 12

The ratio between two carbon isotopes is the same as that of the environment

Question 13

Radiometric dating- Overtime

Answer 13

The unstable (parent) isoptope decays into a daughter ispotope at a constant rate

Question 14

Radiometric- Half-life

Answer 14

Amount of time it takes for 50% of the parent isotope to decay into a daugher isotope

Question 15

Adaptive radiations

Answer 15

Period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities

Question 16

Mass extinction

Answer 16

Geological and paleontological eras are defined by the massive changes in the abundance/composition of the fossil record such as mass extinctions (when large number of species become extinct)

Question 17

what are the 3 doman systems of the tree of life and which are more closely related to eachother?

Answer 17

Eukarya, Archaea and Bacteria
Eukarya and Archaea are more closely related than they are to Bacteria.

Question 18

Serial endosymbiosis

Answer 18

prokaryotic cells engulfed by an ancestral archaea cell