B16: Adaptation, Interdependence and Competition

Population

A group of the same organisms living in an area

Interdependence

Different organisms relying on each other for the survival of the population.

Habitat

The location where an animal lives

Community

All of the populations that live in a habitat

Ecosystem

The interaction between the biotic and abiotic parts of the environment

Abiotic factors

Temperature, Light Intensity, Wind Intensity/Direction, Availability of nutrients in soil, soil pH, Availability of water, Moisture levels, Availability of oxygen (in aquatic organisms), Availability of carbon dioxide

Effects of Abiotic Factors

Temperature → Enzymes

Light Intensity → Photosynthesis

Wind Intensity → Mechanical Damage, Transpiration

Soil pH → Enzymes

Moisture levels → Plants killed by water logging, Transpiration, Photosynthesis

Oxygen availability → Respiration, makes environment acidic

Carbon dioxide availability → Photosynthesis

Biotic factors

Pathogens, Predators, Competition, Food availability

Effects of Biotic factors

Pathogens → Kill organisms

Predators → Disrupts numbers of prey and other organisms

Competition → A new species kills a native species when it outcompetes it

Food availability → Death

When to use random sampling

To estimate organisms in an area or compare difference in abundance in 2 different areas

When to use a line transect

To see if distribution changes as environmental conditions change

Random sampling method

• Determine co-ordinates using a random number generator

• Place quadrats at co-ordinates and measure abundance

• Repeat 10x

• Calculate a mean

• Upscale the mean from the area in a quadrat to the area in the whole field

Line transect method

• Place tape measure from one place to another

• Place quadrat at regular intervals and measure abundance in each quadrat

• Repeat line across the same area in different locations 3x

Equipment needed for random sampling

Quadrat and Random Number Generator

Equipment needed for a line transect

Quadrat and Tape Measure

What do animals compete for

Food, Territory and Mates

Adaptations animals have to compete successfully for food

Poison, Speed, Sharp claws/teeth, Forward facing eyes

Adaptations animals have to compete successfully for territory

Strength, Horns, Long necks, Sharp teeth or claws

Adaptations animals have to compete successfully for mates

Glamorousness, the best singing voice, bright colours

Interspecific competition

Competition between individuals of different species

Intraspecific competition

Competition between individuals of the same species (only the best genes are passed on to the next generation).

Niche

An organism’s niche is it’s role within an ecosystem. It is a description of:

The range of abiotic factors it can tolerate.

The resources in the ecosystem it is able to make use of (e.g available soil nutrients)

It’s interaction with other organisms (biotic factors)

Similar niches cause competition.

What do plants compete for, and why are they needed?

Light, needed for photosynthesis

Water, needed for photosynthesis

Nutrients, needed for growth

Space, needed for growth

Adaptations plants have to compete successfully for light

Big leaves, tall structure, chlorophyll, and the ability to grow quickly

Adaptations plants have to compete successfully for water

Wide or deep roots

Adaptations plants have to compete successfully for nutrients

Wide or deep roots, carnivorous

Adaptations plants have to compete successfully for space

The ability to grow quickly, far seed dispersal

Adaptations

Special features or characteristics that make an organism particularly well suited to the habitat where it lives.

What happens to SA:V ratio as size of organism decreases

SA:V ratio increases. They are inversely proportional.

Extremophile

Organisms that survive and reproduce in the most difficult and extreme conditions. They have adaptations such as enzymes than can cope with high temperatures without being denatured, and the ability to use minerals released into the water in a process called chemosynthesis, to create sugars.

Types of adaptations

Structural - How an organism is built

Functional - Ones which take place inside the organism

Behavioural - How an organism acts

Adaptations of a camel (hot, dry climate)

Structural: Long eyelashes to bat away sands, large SA:V ratio to let off heat, flat hooves to make it easier to walk on desert sands and soils, sandy brown colour to camouflage, humps to store fat which provide energy during daytime.

Functional: Tissues that can cope with large changes in core temperature, a kidney adaptation allowing them to produce very concentrated urine so they need little to nothing to drink, ability to take water from their food.

Behavioural: Most activate in the early morning and evening, where it is cooler, they rest in shady areas or burrows during the day.

Adaptations of a polar bear (cold climate)

Structural: Thick layer of blubber (fat) that builds up under skin, white fur to camouflage in winter, large size to reduce SA:V ratio, which reduces energy transfer to the surroundings, small ears to reduce SA:V ratio, thick fur to provide effective insulation, black skin for heat absorption, sharp claws to grip ice.

Functional: Ability to swim for underwater hunting, antifreeze in cells.

Behavioural: Basking in the sun to absorb energy

Xerophytes

Plants adapted to live in extreme conditions, such as cacti.

Adaptations of a cactus (hot and dry climate)

Structural: Small SA:V ratio, leaves reduced to small spines with a tiny SA, so they only lose small amounts of water, extensive root systems (taproots) can access underground water sources, wide and shallow roots to capture rain as soon as it falls.

Functional: Full of water storing tissue, can take in 1 tonne of water in a day while losing less than 1 glass per day, spines deter animals from eating them.

Behavioural: Stomata close at night to reduce water loss

Adaptations of marram grass (dry and salty climate)

Structural: Tightly curled leaves reduce SA for water loss so it can survive the dry conditions, sunken stomata in hairy pits trap humid air to prevent transpiration (also traps lost water).

Functional: Thick waxy cuticle prevents water loss, can tolerate salty water, leaves collect dew that forms in the cold evenings which is funnelled to the roots.

Behavioural: Stomata close at night to reduce water loss

Environments that extremophiles can survive is

Salt flats, Glaciers, Caves, or deep sea vents.