LIFE MOVES ONTO LAND

Question 1

Marine green algae

Answer 1

Eukaryotes
First on land were mats of bacteria and algae
Land plants evolved from algae
First spores are from ordovician 
likely ancestors of earliest land plants

Question 2

Ordovician land plants

Answer 2

seedless, non-vascular mosses. Akin to modern mosses. Use spores instead of seeds, no multicellular roots, no xylem for transporting water and nutrients. No leaves.

Question 3

Silurian land plants

Answer 3

seedless plants with primitive vascular system (Cooksonia). Rudimentary roots but no true leaves. Have conducting tissues of woody vessels to uptake and transfer water and nutrients which also serves as structural support.

Question 4

Devonian land plants

Answer 4

Lycopod (seedless, vascular) plants, coal swamps.
Plants with leaves and deep root systems with tree sized dimensions.
Evolution of xylem and leaves led to adaptive radiation

Question 5

Devonian land plants - first gymnosperms

Answer 5

(seed plants)

Seeds allow plants to withstand dry conditions by unbinding them from moist, wet conditions.

Question 6

Devonian – Carboniferous: how did evolution of large plants with roots affect global carbon cycle and climate?

Answer 6

Roots pump co2 into soils thereby enhancing chemical breakdown of silicate minerals, which pulls co2 atmospheric levels down

Question 7

Photosynthesis-Respiration Loop for cycling carbon

Answer 7

photosynthesis: takes co2 and water to make organic matter and o2
respiration: takes organic matter and o2 to create co2 and water

Question 8

Significance of carbon BURIAL on atmospheric chemistry and global climate

Answer 8

Causes atmosphere to become more oxygen rich, because trees take in co2, output oxygen and then don’t decompose(which would release the co2). This causes lower co2 levels.

Question 9

Carbon cycle during the Carboniferous Period (“Age of Coal”)

Answer 9

Trees intake co2 and put out oxygen. Most trees die, fall into swamps, where they get preserved. Some die and decompose, releasing co2

Question 10

Organic C burial (Coal Swamps), atmospheric CO2 levels, and climate change during Carboniferous

Answer 10

The carboniferous had a reduced rate of decomposition and high rate of burial of trees. I.e. many trees, which would normally give off CO2 when composing were buried, causing there to be low levels of CO2 in the atmosphere

Question 11

Ordovician/Silurian: first land animals – what were they? BUGS (Trigonotarbids & Millipedes) When do they first appear?

Answer 11

Trigonotarbids appear in the late silurian ~420 Ma. Millipedes appear after, still in the late silurian.