Lecture 4 CM

Question 1

What is biomass?

Answer 1

the total quantity or weight of living organisms in a given area or volume

Question 2

What do the interrelated factors determine in biomass?

Answer 2

the kind, abundance and permanence of biomass in any place is determined by a number of interrelated factors

Question 3

What does biomass reflect?

Answer 3

it reflects circumstances

Question 4

What does the growth form of plants in any habitat reflect?

Answer 4

it reflects the environmental conditions
- e.g. grass, shrub, evergreen etc

Question 5

What are formations aka biome?

Answer 5

they are vegetation types that can be classified based on their predominant growth forms

Question 6

The structure of biomes is predominately governed by?

Answer 6

by the ecology of the dominant plants and vegetation, with the exception of grasslands

Question 7

What are the roles of plants and animals in ecological processes?

Answer 7

plants are the drivers and animals are the passengers

Question 8

Globally biomes are seen to have?

Answer 8

• particular proportions of vegetation growth form
• consistent vertical structure

Question 9

Particular proportions of vegetation growth form examples

Answer 9

• arid or seasonally dry habitats have abundant drought-hardy shrubs
• temperate woodlands are dominated by deciduous tree species
• tropical rainforests have an important canopy epiphyte layer

Question 10

Consistent vertical structure examples

Answer 10

• single vegetation layer in arctic tundra
• multiple vegetation layers in forest biomes

Question 11

What are the 9 principal terrestrial biomes?

Answer 11

1. Arctic tundra
2. Boreal forest/taiga
3. Temperate deciduous forest
4. Temperate evergreen forest
5. Temperate shrubland/Mediterranean scrub
6. Temperate grassland/steppe
7. Desert
8. Tropical seasonal forest/savanna (sub-tropical)
9. Tropical rainforest
   (10. Mountain biome)

Question 12

What does the global distribution of the 9 biomes reflect?

Answer 12

they reflect variations in mean temperature and precipitation

Question 13

What are the 9 biomes distributed at?

Answer 13

they are distributed at specific latitudes within discreet precipitation zones

Question 14

What is latitude?

Answer 14

it is a reliable estimator for mean annual temperature in terms of intensity of solar radiation and relative proximity to the equator and poles

Question 15

Precipitation is not correlated with?

Answer 15

Latitude

Question 16

What is the Hadley cell?

Answer 16

intense solar radiation over the equator drives evaporation and upward convection of air currents, leading to powerful low pressure systems and near constant rainfall at 0-30 degrees N&S of the equator the tropical biome

Question 17

What is the Hadley cell the principal driver of?

Answer 17

it is the driver of the global weather system

Question 18

Where does the continual upward convection drive the dry air to?

Answer 18

it drives the dry air int the high atmosphere to the north and south
- some dry air descends at c.30 degrees N&S, giving rise to the dry, hot desert biome
- the remaining air currents continue to move N&S, eventually descending at the poles in the dry, cold polar cell

Question 19

What is the Ferrell cell?

Answer 19

low lying warm air moving north from the desert biome gathers moisture and collides with cold air moving south from the polar cell

Question 20

What does the Ferrell cell sustain?

Answer 20

it sustains the cold, moist temperate biome

Question 21

What do zones of high pressure comprise?

Answer 21

they comprise dry air masses descending from the upper atmosphere (building up air pressure at sea level) and produce little precipitation
- desert regions, polar regions

Question 22

What do zones of low pressure comprise?

Answer 22

they comprise moist air masses rising into the atmosphere (reducing air pressure at sea level) and produce abundant precipitation
- tropical regions, temperate regions

Question 23

What drives the latitudinal distribution of biomes over the surface of the earth?

Answer 23

the relationship between the Hadley and Ferrell cell