A.D. Tropical Environments - Rainforests, Savannah

Question 1

What are the climatic conditions in tropical rainforests?

Answer 1

• high annual rainfall: 2000-10000mm
• high average temperatures: 29 degrees
• high humidity: 80%
• stable conditions throughout the year - only 5 degrees difference

Question 2

What are the 4 layers of the rainforest?

Answer 2

• emergent
• canopy
• understory
• forest floor

Question 3

Describe the Emergent layer:

Answer 3

• up to 60m tall - only tall trees
• intense sunlight, dry conditions
• lower transpiration - waxy leaves
• lightweight seeds - easier wind pollination
• animals: large birds of prey - Crowned eagle

Question 4

Describe the Canopy:

Answer 4

• 30-45m tall
• rich in vegetation, thick and dense
• a roof - blocks sunlight, rainfall
• seed dispersion through fruit droppings
• animals: parrots, tucans, spider monkeys, sloths

Question 5

Describe the Understory:

Answer 5

• darker, more humid - beside rivers
• shorter plants that adapted to low light conditions
• colourful or aromatic plants to attract pollinators
• animals: predators-jaguar, frogs, snakes

Question 6

Describe the Forest Floor:

Answer 6

• low sunlight - difficult for plant to grow
• decaying matter
• animals: okapi, tapir

Question 7

How does the vegetation interact with the climate in the rainforest?

Answer 7

• high temperature, humidity is ideal for growth - most diverse ecosystem
  -high net primary productivity - more than 2x more than in savannah
  -adaptations: carnivorous pitcher plants get nutrients from other species
  lianas require only small amount of nutrients
  animals have adapted to plant toxicity - synchronised fruiting - not practical source of food
  buttress roots - stability
  pollination with insects, bats

Question 8

What affects the nutrient cycle in the rainforest?

Answer 8

• amount of soil erosion - material dissolved
• amount of rainfall - higher runoff
• rates of decomposition - increased with high humidity
• nature of vegetation - woody hold nutrients

Question 9

Describe the nutrient cycle in the rainforest:

Answer 9

• gain in soil by weathering - lost by leeching
• gain in biomass by uptake from soil - lost by fallout pathway onto litter
• gain in litter from precipitation - lost by runoff
• gain in soil by decay pathway from litter

Question 10

What are the climatic conditions in the Savannah?

Answer 10

-hot: Tropic of Cancer and Capricorn
-alternating wet and dry conditions: floods, drought
mean annual rainfall: 800-1600mm
driest month: 60mm annually
mean annual temperature: 20-30 degrees
differences between night and day temperatures

Question 11

How do the winds affect the conditions in the Savannah?

Answer 11

• summer: on shore winds bring rain from water

- winter: off shore winds from the land to water keep the climate dry

Question 12

How do soils change during wet and dry seasons in the Savannah?

Answer 12

-wet season: leaching of nutrients, minerals that get deposited deep in the soil
-dry season: minerals get brought back up to the surface because evapotranspiration increases
-following wet season: upper horizon of iron oxides formed from leaching of surface nutrients forming an impermeable crust - laterite
=not very fertile, poor for agriculture

Question 13

Describe the nutrient cycle in the savannah:

Answer 13

• gain in litter from precipitation - loss by runoff
• gain in soil from litter and weathering - nutrients get stored as a protection from fire
• loss in soil through leaching
• biomass gains from the soil

Question 14

How does fire impact the vegetation in savannah?

Answer 14

• mineralises litter layer
• kills off weeds, competitors or diseases
• prevents over colonisation