B4.2 Ecological Niches

Obligate aerobes

Cannot function without continuous oxygen (e.g,: all plants and animals)

Obligate anaerobes

Killed by oxygen (e.g: tetanus bacteria)

Facultative anaerobes

Can respire aerobically or anaerobically (e.g: yeast, E-coli)

Stages in holozoic nutrition

• Ingestion →Taking food into gut

• Digestion →Breaking large food molecules into smaller molecules

• Absorption → Transport of digested food across the plasma membrane

• Assimilation →Using digested foods to synthesis proteins and other macromolecules

• Egestion →Voiding undigested material from the end of the gut

Autotrophs

Make their own carbon compounds

Transpiration

Evaporation of carbon dioxide from stomata of leaves

Stomata

Pores in leaves that open and close for gas exchange to happen

Heterotrophs

Obtain energy from other organisms

Obligate Mixotrophs

Must use both auto and heterotrophic nutrition

Mixotrophic nutrition vs Holozoic nutrition

Mixotrophic Nutrition	Holozoic Nutrition
Are autotrophic and heterotrophic	Form of heterotrophic nutrition
Can use whichever nutrient	Involves ingesting of an organism

Saprotrophs

Secrete digestive enzymes into dead organisms and digest it externally

3 domains of life

• Archaea

• Bacteria

• Eukaryotes

Functions of teeth

• Incisors → Biting chunks

• Canines → Ripping or tearing

• Premolars → Slicing or crushing

• Molars → Grinding

Folivore

Organisms that mostly eat leaves

Frugivore

Organisms that mostly eat fruit

How do giraffes adapt to eating plants

• Specialised teeth

• Long necks

• Specialised digestive system

• Tough tongue

Categories of adaptations

• Structural

• Chemical

• Behavioural

Epiphytes

Plants that grow around other plants for support

Range of tolerance

Environmental conditions tolerable for survival

Ecological theory

Every species must have a realised niche that differs from the realised niches of all other species if it is to survive in an ecosystem