Unit 6: Ecosystems And Climate Change

Question 1

Habitat

Answer 1

An ecological or environmental area that is inhabited by a particular species, community, or population.

Question 2

Adaptations of grasses to sand dunes

Answer 2

• thick waxy cuticles (to limit transpiration)
• sunken stomata + epidermal hair (water condenses during transpiration)
• leafs roll up during droughts (water vapour is not lost)
• long extensive roots (to extract water)
• accumulation of fructans (complex sugars) in roots and leafs to increase osmotic potential and water uptake

Question 3

Adaptations of mangrove swamps

Answer 3

Develop on the coast in the tropics and subtropics where mud accumultates. They are flooded with seawater at high tide. Dominant species are trees.
- secretion of excess salt from leaves (salt conc disrupt amount of water plant can absorb).
- root epidermis is suberized (a fatty substance) to reduce salt permeability
- cable roots growing close to soil surface (to take in oxygen)

Question 4

Abiotic variables

Answer 4

Non-living things. Temperature, water availability. For plants: soil pH, soil salinity, availability of mineral nutrients, light intensity + animal things

Question 5

Limiting factors

Answer 5

Any variable that slows life processes or stops a population from growing.

Question 6

Range of tolerance

Answer 6

Levels of environemtnal factors beyond which an organism can’t survive (optimum). The adaptations of a species gives its range of tolerance. Outside of that, its zones of stress.

Question 7

Coral reefs

Answer 7

biodiverse marine ecosystems that can only develop where conditions are suitable for hard corals. Mutualistic relationship with zooxanthellae (need light for photosynthesis).
-Depth should be less than 50 for light
-pH should be above 7.8 to allow deposition of CaCO3 in the skeleton of coral.
-Salinity between 32 and 42 parts per thousand of dissolved ions to avoid osmotic problems
-Clarity to allow light to pass through water
-Temperature 23-29C for it to remain healthy

Question 8

Biome

Answer 8

Large geographic unit comprising groups of ecosystems with similar abiotic conditions and communities defined by their climate and plant dominate species.

Question 9

Temperate forest

Answer 9

Moderate temp (warm summer cold winter), seasonal variation, rainfall medium to high, light intensity moderate (limits productivity)