Ecosystems & Populations Chapters 4 & 5. Levels of Organization in Ecology Ecologists study...
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Transcript of Ecosystems & Populations Chapters 4 & 5. Levels of Organization in Ecology Ecologists study...
Levels of Organization in Ecology
• Ecologists study individual organisms, but this only provides part of the story of its life cycle.
• An individual organism interacts with others of its species; it is also dependant on other organisms for food, shelter, reproduction and protection.
Levels of Organization in Ecology cont.
• Population – a group of organisms of one species that interbreed and live in the same place at the same time
• Members of the same population may compete with each other for food, water, and other resources.
• How organisms share the resources determines how far apart organisms live and the size of the population.
Levels of Organization in Ecology cont.
• Community – a collection of interacting populations
• A change in one population in a community will cause changes in the other populations.
Levels of Organization in Ecology cont.
• Ecosystem – made up of the interactions among the populations in a community and the community’s physical surroundings
• Terrestrial, freshwater and saltwater (marine) ecosystems are the three major kinds.
Levels of Organization in Ecology cont.
• Biome – a large region characterized by a specific climate and certain plants and animals
• Biosphere – the portion of Earth that supports life
• The biosphere extends from high in the atmosphere to the bottom of the ocean.
Organisms in Ecosystems
• Habitat – the place where an organism lives out its life
• Niche – the role and position a species has in its environment – how it meets its needs for food and shelter, how it survives and how it reproduces.
Niche
• Several species may share a habitat, but the food, shelter, and other resources of that habitat are used in different ways.
• These differences lead to reduced competition.
• It is an advantage for a species to occupy a niche different from those of other species.
Living Relationships
• Predator-Prey Relationship – beneficial for one species and harmful to another, involves a fight for survival.
• However, some species enhance their chances of survival by forming close, permanent relationships with other species - symbiosis.
Symbiotic Relationships
• Commensalism –relationship in which one species benefits and the other species is neither harmed nor benefited
• The clownfish lives among the stinging tentacles of an anemone and is protected from potential predators not immune to the sting of the anemone.
Symbiotic Relationships cont.
• Mutualism – relationship in which both species benefit
• Some fish and shrimp clean the bodies and mouths of large fish and turtles.
• The cleaner fish get a meal while the large fish have parasites removed.