Community Interactions

Community Interactions Powerfully affect an ecosystem Include: Competition Predation Symbiosis

Competition When organisms of the same or different species attempt to use an ecological resource at the same place and the same time Resource any necessity to life Plants and animals compete Winner and losers

Rules, rules, rules Fundamental rule in ecology Competitive Exclusion Principle No two species can occupy the same niche in the same habitat and the same time Prevents competition

Predation Interaction where an organism captures and feeds on another organism Predator Organism that does the killing and eating Prey Organism that is being killed and eaten (victim)

Symbiosis Any relationship where two species live closely together Symbiosis literally means “living together” 3 main types Parasitism Mutualism commensalism

What type of relationship is this? Who is helping who?

Mutualism Both species benefit from the relationship A Happy couple Flowers and bees Flowers need bees for pollination, bees need flowers nectar

What type of relation ship is going on here? Who is helping who?

Commensalism One member of the relationship benefits while the other is neither harmed nor helped One-sided Food or shelter Barnacles on whale

Ants and aphids

What type of interaction is going on here?

Parasitism One organism lives on or inside another organism and harms it Parasite obtains all or part of its nutrients from the other organism Host Organism that is harmed in relation ship; the one that provides the nutrients to the parasite Parasite Organism that gets its nutrients from the host Do they want to kill their host? No, because they need them…they will weaken or hurt the host in some way

Recap What are the three types of interactions in a community? Competition Predation Symbiosis What types do we have? Mutualism Commensalism Parasitism

Ecological Succession Do all ecosystems stay the same all the time? What are some things that cause changes to ecosystems? Natural and unnatural Quickly and slowly

Ecosystems are constantly changing in response to human and natural disturbances. As an ecosystem changes, older habitants die out and new organisms move in, causing more change

Ecological Succession Series of predictable changes that occur in a community over time Physical environment Natural disturbance Human disturbance

Primary Succession Succession on land that occurs on surfaces where no soil exists Volcanic eruptions Glaciers melting

Stages of Primary Succession Start with no soil, just ash and rock First species to populate this area “pioneer species” For example, pioneer species on volcanic rock are lichens (LY-kunz) Lichens made up of fungus and algae that can grow on bare rock When lichens die, they for organic material that becomes soil…now plants can grow

Secondary Succession Succession following a disturbance that destroys a community without destroying the soil Natural hurricane fires Human disturbances Farming Forest clearing

Succession in Marine Ecosystems Deep and dark Can succession happen? 1987 dead whale off of California Unique community of organisms living in remains Represents stage in succession in an otherwise stable, deep-sea ecosystem Whale-fall community

Whale-Fall Succession Begins when large whale dies Sinks to barren ocean floor Scavengers and decomposers flock to carcass , our first community Amphipods Hagfish sharks After a year, most tissues have been eaten Now, second small community of organisms live here Body is decomposing, releasing nutrients into the water Small fishes Crabs Snails worms Only skeleton remains… Third community moves in Heterotrophic bacteria Decompose oil in bones release of chemical compounds Who uses these chemical compounds? Chemoosynthetic autotrophs In come the crabs, clams, and worms that feed on this bacteria

Study Chemical reactions, enzymes, and Chapters 3 and 4 Teacher,