Biomes

Biome: a large community of plants and animals that has developed as a result of environmental factors

Abiotic Factors as the determinants of terrestrial biome distribution

--> earth temperature and annual rainfall are the two main abiotic factors which determine the distribution of terrestrial biomes

Regions that experience similar abiotic factors will contain the same biome

The ecosystems found in equivalent biomes in different parts of the world contain similar communities

--> due to shared abiotic factors and resultant convergent evolution

Adaptions to biomes: traits that increase survival chances in a specific environment

--> come about by the process of natural selection

Hot dessert

Very high daytime temperature, very low night time temperatures

Little water availability due to low annual rainfall

Limited soil development

Predators and little shelter

E.g. saguaro cactus

• Stem has a thick waxy cuticle to reduce water loss by evaporation

• Spines instead of leaves, reduced the surface area of which water can be lost by transpiration

• Cells in the stem can expand to take on and store water

• A deep tap root enable access to water deep under ground

• Shallow surface roots allow fast absorption of any water form rainfall

E.g. Kangaroo rate

• Spend daylight hours in underground burrows, allows them to avoid daytime temperatures

• Can extract enough water from their diet to produce high concentrated urine

Tropical Rainforest

E.g. Kapok tree

• Rapid growth allows them to absorb enough sunlight

• Wide buttress roots provide a sturdy base to support the trees in growth

E.g. Orchid Mantis

• Appears similar to an orchid flower enabling it to attract insects as prey

• Small and pain allowing to to camouflage amongst stems and branches of plants