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Species Interactions & Community Ecology. Environmental biology. Case Study. Mussels & the Great Lakes Border of US and Canada 5 giant lakes & a number of small ones These were formed by the last Ice Age More polluted in the past
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Species Interactions & Community Ecology Environmental biology
Case Study • Mussels & the Great Lakes • Border of US and Canada • 5 giant lakes & a number of small ones • These were formed by the last Ice Age • More polluted in the past • Took ‘Big Government’ intervention to clean up - Clean Water act, 1970 • Arrived by ship from Europe
Case Study cont… • Within 2 years the mussels had established themselves in all the Great Lakes • Then spread even further to the great Mississippi River Watershed - 40% of US land mass. • Their main limiters were absent here • Predators • Competitors • Parasites
Case Study cont……. • IMPACT • = Economic mostly • = industrial interference • = infrastructure damage • = Ecological • = Overeat the native phytoplankton • = Kill local molluscs • = Alter local ecology towards bottom dwellers • Permit more light penetration • Deposit organic matter on bottom
Case Study cont……. • However, recently they are being replaced by another species • Quagga mussel is moving in • It is reducing the zebra mussels • What impact this new one shall have? We will have to wait and see….
INVASION!!!!! • Look up and see. They are coming… • ___________
What is ecology? • The study of how organisms interact with each other and their physical environment.
Species Interactions • Species interact with each other • Many ways have been studied and documented • Some are beneficial to both species • Other to one or the other • And some to neither….
Competition • Intraspecific - within a species • Example = _______________???? • Interspecific - between species • Example = _______________???? • Solution is resource partitioning = basically sharing by adapting • There is a total negative effect on both!
Predation • One species kills the other to live • Predator is the killer • Prey is the victim • Example = _______________???? • Drives evolution - Natural selection • These interaction are direct and do generally cycle…
Parasites • No immediate death involved • Example = _______________???? • Parasite depends on the host for food and shelter • The host is harmed to some degree! • The parasite benefits entirely • Co-evolution also works here
Herbivory • Animals feed on plants • Insects on plants • Example = _______________???? • Plant does not die (at least not initially) • Plants defend themselves too • Example = _______________???? • Evolutionary Arms Race!
Mutualists • Both are good for each other • Provide other with something it needs • Example = _______________???? • Symbiotic • Example = _______________???? • Pollination • Example = _______________????
Ecological Communities • Each has its; • Producers - make food • Consumers - • Primary - grasshoppers • Secondary - frogs • Tertiary - birds • Decomposers - Nonliving organic consumers • recyclers
Food chains & Energy • As one feeds on another, in a community, there is a relationship built - this is known as the food web. • As one moves further away from produces then amount of energy available is reduced (by 90% per level) • Energy Pyramid
Keystone Species • If you were to eliminate a single species from a community and see the effects of that action, one would notice: • Most have little impact • One will devastate the ecosystem • This one species is the keystone species • Example = _______________????
Ecological Succession • A new volcanic island will be populated by life in a predictable way; • Primary succession - No life at beginning • Primary species = first • Example = _______________???? • Secondary succession - Some form of life or organic matter remains - and it starts with that. • WATCH ME!
Biomes • What are they? • Just regions of the planet with certain similar communities of life. • The Earth has 12 such regions • http://www.youtube.com/watch?v=ag5ATGEplbU
Biomes… • In general, there is no sharp demarcation between biomes. • Life on Earth is a continuum based on moisture and heat…
Other Biomes… • Also, there are aquatic biomes too… • These are considered later in the course