Interactions Within an Ecosystem Interactions is an ecosystem are influenced by the fact that all organisms are trying to meet at least one of their basic needs – food, water, shelter and space.

Ecosystem – All of the populations that live in a certain area and everything that affects them. (both abiotic and biotic )

Abiotic – all the physical (non-living) parts of the environment that affect organisms living in the area. –Temperature –Water –Soil –Air –Sunlight

Biotic – all living organisms and the organic matter they produce, such as dead leaves and molted skin.

How do you know if something is “living”? Every living thing is made up of one or more cells Living things sense and respond to change Living things have DNA Living things reproduce Living things use energy Living things grow and develop

Niche - the ecological role of an organism in a community especially in regard to food consumption. –Every organism in an ecosystem occupies a niche (plays a role), such as – producers, consumers, decomposers, etc.

3 ways species interact within an ecosystem: I.Competition II.Predation III.Symbiosis

1. Competition – Occurs when 2 or more organisms or populations try to use the same limited resource.. (ex. different species of trees compete for living space and sunlight)

Limiting factors – When one or more of the essential needs of a population (food, water, shelter) becomes scarce then the ecosystem cannot support all organisms of a population, the strongest and smartest will survive.

Carrying capacity – The largest population that can live in an ecosystem. When a population grows larger than the ecosystem’s carrying capacity, limiting factors cause the population to get smaller.

2. Predation – Certain species interact with each other by hunting and killing other species.

Predation Niches Prey – the animal that is hunted, killed, and eaten. Prey have developed many adaptations to keep from getting killed (ex. camouflage, strength in numbers, speed, bright colors, etc.)

Predator – the animal that hunts, kills, and eats another animal. Predators have developed many adaptations to allow them to be better hunters (ex. speed, traps, hunting in packs, sharp claws and teeth, etc.)

3. Symbiosis – A close, long-term association between 2 or more species. 3 types – Mutualism, Commensalism, Parasitism

Mutualism – Both organisms are helped in the interaction –Ex. Birds eat leechs out of a crocodile’s mouth obtaining food, the crocodile gets cleaned off.

Commensalism – One organism is helped while the other is unaffected Ex. Remoras “hitch” a ride on sharks eating scraps of food left behind and sharks are unaffected.

Parasitism – One organism benefits from the relationship (parasite) and the other is harmed (host) Ex. Ticks / fleas on a dog using blood to survive while harming your dog.

Practice – add as examples to notes Mutualism Parasitism

Mutualism Parasitism

Mutualism Commensalism

Mutualism Parasitism