What shapes an Ecosystem?

Biotic and Abiotic Factors• Biotic Factors – biological (living)

influences on organisms within an ecosystem.

• Abiotic Factors – non-living factors that shape an ecosystem.

• Key point – together, biotic and abiotic factors determine the survival and growth of an organism and the productivity of the ecosystem in which the organism lives.

• What are some biotic factors?

• Abiotic?

• Biotic factors include the type of animals that live in the ecosystem, and the type of food available for organisms.

• Abiotic factors include how much water is available, are there sufficient areas for the animals to breed?

Areas within an Ecological System.

• Habitat – The area where an animal lives that includes both abiotic and biotic factors.

• Niche – (nitch) – a habitat supplying the factors necessary for

the existence of an organism or species – the full range of physical and biological

conditions in which an organism lives and the way in which the organism uses those conditions.

Areas within an Ecological System.

• Examples of niches of organisms include– Its place in the food chain– The range of temperatures it needs to survive– The type of food it eats– How it gets its food– How it reproduces

Let’s look at a particular organism’s niche

• Place in the food chain?• Temperatures need to survive?• Type of food it eats?• How it gets its food?• How it reproduces?

No two species can share the same niche in the same habitat.

This is a fundamental rule in ecology called:

The Competitive Exclusion Principle(also called Gause's Law)"complete competitors cannot coexist"

Community Interactions• Community interactions such as• competition, • predation, • and various forms of symbiosis, • can powerfully affect an ecosystem.

A look at Community Interactions

• Competition (-/- interaction), - occurs when organisms of the same or different species attempt to use an ecological resource in the same place at the same time.

– Resource can refer to food, water, nutrients, light or space.

– Competition results in a winner and a loser. What happens to the loser in an ecological system?

• Predation • (+/- interaction), –

An interaction where one organism captures and feeds on another organism.

• Symbiosis –Any relationship where two organisms live closely together

- Mutualism (+/+ interaction),

both species benefit from the relationship. Ex: flowers and bees

- Mutualism (+/+ interaction), both species benefit from the relationship.

- Mutualism (+/+ interaction), both species benefit from the relationship.

- Commensalism – One member of the association benefits, but the other is neither helped, nor harmed.

Ex: Whale with barnacles.

In commensalism (+/0 interaction), one species benefits and the other is apparently unaffected

Commensal interactions are hard to document in nature because any close association likely affects both species

Commensal interaction between cattle egret and

water buffalo

- Parasitism- (+/0 interaction), - One organism lives

on or in another organism and harms it.

- Ex: tick

Parasitism

Parasitism

ParasitismColonoscopy Demonstrating

a Moving Ascaris Worm

Doctors at a clinic in central Serbia, have removed an 11 centimeter-long Ascaris intestinal worm from a woman's eye socket.

The parasite had probably travelled through the patient's blood from the digestive tract into the eye socket

Ascaris lumbricoides life cycle

Parasite Article

• Create a table to include:– Name of organism– Two ways that people get it– Three symptoms– Who is at risk– How to prevent it