Ecological niches

Define ecological niche

Role of an organism in an ecosystem

• Growth of individual 

• Survival of individual

• Ability to reproduce

• Mode of nutrition

• Interactions with other species

• Interactions with its own species

What is obligated anaerobes

Cannot survive in the presence of oxygen

What is facultative anaerobes

Can survive in the presence or absence of oxygen

Obligated aerobes

Cannot survive in the absence of oxygen

Define autotrophic nutrition (and 2 types)

Organisms that produce their own foods

• Photoautotrophs: Uses light energy to convert CO₂ into sugar

• Chemoautotrophs: Uses energy from chemical reactions involving inorganic substances. Eg some bacteria and archaea use chemicals like hydrogen sulphide and ammonia

Define heterotrophic nutrition

Organisms that cannot make their own food and takes it from other organisms

Define Holozoic nutrition

A type of heterotrophic nutrition where organisms:

Ingest → Internally digest → absorbs and assimilate nutrition from digested food

Define mixotrophic nutrition and 2 types

Can behave like autotrophs or heterotrophs

Obligated mixotrophs: Requires both autotroph and heterotrophic modes of nutrition to survive

Facultative mixotrophs: Can switch between the 2 modes of nutrition based on available resources

Define Saprotrophic nutrition

Heterotrophs that obtain nutrition by external digestion of foods

Release digestive enzymes → Externally digest food → Absorb and assimilate digested food

Define detritivores

Heterotrophs that obtain carbon compounds from dead organisms by internal digestion (worms, vultures)

What are archaeas

one of the 3 domains of life

Prokaryotes that are found in a wide variety of environments and are metabolically diverse

• Phototroph: Use light energy to produce atp NOT photosynthesis (no O₂ produced)

• Chemolithotroph: oxidise inorganic compounds to produce atp

• Organotrophs: Oxidise organic compounds (sugars and fatty acids) to produce atp)

How does hominid dentition help scientists

Scientists can make predictions about the diet of extinct species (like hominids) by examining the anatomy of fossils and comparing them to the anatomy of living descendants

What are the adaptations of plants against herbivores

Physical: Thorns on blackberry bushes, Sharp trichomes on stinging nettles, Grass, fern, etc have tough fibrous leaves

Chemical: Chilli plant produce capsaicin in fruits and seeds which causes burning sensation, Tobacco plants produce toxin nicotine to deter herbivours (tobacco hawk moths evolved to detoxify nicotine)

Adaptation of grazing mammals

• Flat molars for grinding grass

• Teeth continue to grow throughout life so they don’t become worn down

Herbivore insect adaptations

• Chewing mouth parts: strong mandibles with serrated edges that are able to cut through cell walls in leaves of plants. Strong muscles to manipulate mandibles

• Piercing mouthparts: Aphids have stylets which they insert directly into phloem of plants to obtain nutrients in phloem of plants

Adaptations of predators

Physical

• Sharp claws and talons: Grip and hold prey

• Powerful jaw and teeth: Aid predators to capture and kill prey

• Speed and agility: Use speed to chase and catch prey

• Camouflage: Blend in with environment to stealthily approach prey or wait in bush to ambush prey

Chemical: Venom glands to immobilise or kill prey animals (komodo dragons, snakes, scorpians)

Behavioural:

• Hunting in packs: Overwhelm large prey

• Ambush tactics: Lie in wait for prey to come within striking distance.

Adaptations of prey

Physical

• Armour or protective coating: Spikes, shells, exoskeleton

• Swift and agile: outrun and avoid predator

• Camouflage: high from predator

• Mimicking enviro or dangerous species

Chemical

• Toxicity

• Unpalatable chemicals

Behavioural:

• Travelling in groups: Protection for individuals

• Swarms: Confuse predators

• Alarm calls

• Nocturnally or diurnally: Avoid times when predators are most active

Adaptations of Canopy trees

• Height and crown structure: Tall trunks to reach sunlight. crown maximise absorption of light

• Broad leaves: maximise absorption of light. Leaves arranged to minimise self shading

Liana vines

• Climbing mechanisms: Climbs trunks of canopy trees to reach light. Twisting around trunks or use adhesive pads or hoods

• Rapid growth: Allows lianas to reach light quickly

• Flexible and think stems: Grow around obstacles as they grow toward light

• Large broad leaves: Maximise light absorption for photosynthesis

Epiphytes adaptations

Grow

Strangler epiphyte adaptations

• Germinate in branch of canopy trees and send aerial roots towards ground

• Eventually surrounds trunk of host, out competes it for light. 

Shade tolerant plant adaptations

• Branching: increase surface area for absorbing light

• Broad leaves

• High concentration of chlorophyll

Define fundamental niche

Niche that organism could potentially occupy in the absence of competition

Define realised niche

Niche that organism does occupy due to competition

Define competitive exclusion

No 2 species can occupy the same niche, one will be better adapted for the nich, and out compete and exlude the other specie