B4.1 Adaptation to environment

Habitat

Habitat

A place where organisms live

If more than one species has similar requirements than it can be a place for a community

→ Provides basic requirements for life

→ Described by geographical/physical location + type of ecosystem

→ Organisms impact each other

Sand dune grass species

Species: Sea oat (Uniola paniculata)

Drought resistant, shallow root systems, narrow leaves

Root systems maximise water intake and hold sand in place, prevent erosion

Thrive in sun, tolerate salt spray

Produce nodes and rhizomes near base, asexual growth shoots produce shoots above it

Sexual reproduction accomplished with seed head production

Mangrove tree species

Species: Red mangrove (Rhizophora mangle)

Grows in saltwater tidal zone

Prop roots extend above water line, build system and absorb air for root tissues, filter salt out of water

Tangled roots provide habitat for marine animals

Produce fruit that germinates before leaving (propagule), falls and absorbs water, orients itself in shallow water with roots downwards

Abiotic factors

Non living components of an ecosystem e.g water availability, temperature range, light intensity/duration, soil composition, pH range, salinity

Effect of an abiotic factor

Can and do limit a population if it is out of tolerance range

Examples of organisms in unusual habitats

Red mangroves (high salinity shorelines)

Sea oats (sandy soil beaches)

Polar bear (low air temperature in arctic regions)

Thermophilic bacteria (water at 60-80C temp)

Optimums usually higher/lower for these so little competition

Limiting factors

Factor limiting population size or presence of a particular species in a habitat

→ Possible to work out what this is by collecting data measuring species abundance + factor level

Coral reef formation

Found in less than 1% of ocean, 25% of marine species live in them

Symbiotic relationship between coral polyps + microscopic algae (zooxanthellae)

Effect of water depth on coral reefs

Light only gets to shallow depths, zooxanthellae needs light

Effect of water temperature on coral reefs

Corals need 20-80C, if higher corals get stressed and expel zooxanthellae→ bleached coral

Effect of salinity on coral reefs

Corals needs correct salt levels, fresh water run off makes this suitable

Effect of water clarity on coral reefs

Corals need clear water for light to get through, sediment/pollution decreases it so light can’t get through

Effect of water pH on coral reefs

Increased CO2 in water leads to lower pH (acidification), less calcium carbonate to build reefs

Biome

Large geographical area containing communities of plants/animals adapted to the environment

Often named after dominant vegetation

Can exist in multiple locations on Earth

Characterised by temperature and rainforest

Subdivided based on other environmental conditions

Ecosystem

Made of physical environment and the plants/animals living there

Plants and animals in similar biomes

Although geographically separated, may have similar morphology and physiology because of convergent evolution

Similar species in same biome

Often genetically related, result of adaptive radiation (have fairly recent common ancestors)

Carnivorous plants

Independently adapted to low nitrogen soil by evolving to catch and digest insects

Hot desert biome

Low rainfall, hot days, cold nights

Sparse vegetation, spines for leaves, burrowing animals active during night

Grassland biome

500-950mm annual rainfall, temperature varies between -20-30C, dry and wet seasons

Mostly grass, animals are mostly grazers

Tundra biome

-40-80C, low precipitation, long dark winters

No trees, frozen soil, animals hibernate or migrate

Taiga biome

Cold winters, -40-20C, 300-900mm annual rainfall

Conifer trees, animals adapted to cold

Temperate forest biome

Four seasons, no extreme temperatures, abundant rain

Deciduous trees, variety of animals

Tropical forest biome

High rainfall, warm temperatures, nutrient poor soil

Very high plant and animal biodiversity

Saguaro cactus

(Carnegiea gigantea)

Native to Sahara desert

Thick, waterproof skin with bristles to defend from grazers

Single long taproot retrieving deep water, shallow roots absorb occasional rainfall

Fennec fox

(Vulpes zerda)

Native to Sahara desert

Large, highly vascular ears to help heat dissipation and locate small underground prey

Nocturnal, spend days in underground dens

Kidneys adapted to reabsorb most water passing through them so they can obtain water from food

Kapok tree

(Ceiba pentandra)

Forms upper canopy in Costa Rica and Amazon

Buttress roots create strong foundation for growth

Poison dart frogs

Lay eggs in small water pools in canopy plants

Toxic chemicals in skin due to diet of poisonous insects

Bright colours/patterns warn predators so not eaten