1.2 Ecosystems Ecosystem – a part of a biome in which abiotic (non-living) factors interact with biotic (living) components Can be many hectares of land, or the size of an old log. Within an ecosystem, there are many habitats. The habitat of the red fox often includes the edges of forests or marshlands

Abiotic Interactions in Ecosystems It is the abiotic components that allow the biotic components to survive in an ecosystem. Abiotic factors include : Oxygen - produced by green plants & micro-organisms. Water - necessary for all life. Nutrients - for growth. Light - required for photosynthesis. Soil - contains water & nutrients.

Biotic Interactions in Ecosystems Community: all organisms that interact within an ecosystem. Population: all members of a certain species within an ecosystem. Species: all organisms within an ecosystem that have the same structure & who can reproduce with each other (and produce fertile offspring).

Species can have many types of relationships in a population. Symbiosis refers to the interaction between the members of two different species. Commensalism - one species benefits, one is not affected For example, the barnacles on a whale Mutualism - both species benefit For example, a bee gathering nectar from a flower Parasitism - one species benefits, the other is harmed For example, hookworm living in dogs

COMMENSALISM

COMMENSALISM (Biological hitch-hiking) The Imperial shrimp hitches a ride on a large sea cucumber. It rides along through areas of potential food, at no cost to the other organism. Anyone home? The pearlfish is a small fish (5-10cm) that lives inside a seacumber in the day and at night, exits through the anus of the seacumber to feed.

MUTUALISM

MUTUALISM Leaf Cutter Ants Cut the leaf.. These ants cultivate (grow) a fungus. They feed the fungus and the fungus serves as their food! Chew into a pulp Store the pulp with ant feces and fungus spores Teachers' Domain: Ancient Farmers of the Amazon Fungus begins to grow...

MUTUALISM LICHEN = algae + fungus Fungus provides a place for the algae to live. It also provides moisture that the algae needs. The algae provides food (glucose) for the fungus through photosynthesis.

PARASITISM

PARASITISM MOUTH HOOK WORMS The common way for hook worms to enter is through the skin (walking barefoot)... A parasitic worm that lives inside the intestines of its host (mammal). These worms such blood from the host’s intestinal walls ...this leads to anemia (iron deficiency).

PARASITISM The Pine Beetle The pine beetle has infested lodgepole pine trees in BC’s Central Interior. Burrows in the tree, feeds on trees phloem (nutrients) and lays its eggs.

Niches, Competition and Predation Niche: the role an organism has within an ecosystem. also refers to the environment in which a species prospers Competition: occurs when a limited resource is desired by 2 or more individuals in a niche. this limits the size & health of individual organisms, & perhaps the population . Predation: the relationship between the “eaters” & the “eaten”. Predators have adaptations to help them catch prey. Prey have adaptations to help avoid predators. Eg. spines & shells, camouflage and mimicry.

EXAMPLES OF PREDATOR-PREY MODELS

Biodiversity in Ecosystems Biodiversity: the variety & number of different individuals & species in an ecosystem. Healthy ecosystems generally have high biodiversity. Most biodiversity losses occur from the loss of habitat. Humans often have a negative impact on biodiversity. Ecological management programs try to balance human progress with maintaining biodiversity. Take the Section 1.2 Quiz