Interactions Between Living Beings
Living organisms do not exist in isolation. They constantly interact with each other and their environment.
Types: Symbiosis, Predation, Competition
Why study interactions?
- Understanding dependency
- Ecosystem balance
- Energy transfer
Symbiosis - Living Together
Symbiosis is a close, long-term interaction between two organisms.
Greek: sym (together) + biosis (living)
Three types:
- Mutualism
- Commensalism
- Parasitism
Mutualism - Both Benefit
In mutualism, both organisms benefit.
+ Both Win
Examples:
- Bee and Flower
- Rhizobium & Legumes
- Clownfish & Anemone
- Oxpecker & Buffalo
- Lichen
Commensalism - One Benefits
One benefits, other unaffected.
+ One Benefits ○ Unaffected
Examples:
- Remora & Shark
- Barnacles on Whale
- Orchids on Trees
- Birds in Trees
- Egret & Cattle
Parasitism - One Harms Other
Parasite benefits at host's expense.
+ Parasite - Host
Examples:
- Mosquito & Human
- Tapeworm
- Tick on Dog
- Cuscuta on Plants
- Head Lice
Predation - Hunter & Prey
Predator hunts, kills, and eats prey.
Controls population and transfers energy.
Examples & importance:
- Lion → Zebra
- Hawk → Mouse
- Snake → Frog
- Population Control
- Natural Selection
- Energy Transfer
Competition - Struggle for Resources
Competition for limited resources: food, water, space, mates.
Types & examples:
- Intraspecific
- Interspecific
- Plants for Resources
- Animals for Mates
- Effects on Evolution
Food Chain & Food Web
Food Chain: Linear sequence of who eats whom.
Food Web: Interconnected food chains.
Grass → Grasshopper → Frog → Snake → Eagle
Key concepts:
- Producers
- Primary Consumers
- Secondary Consumers
- Apex Consumers
- 10% Energy Rule
- Food Web Stability