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Explore the concept of emergent properties and self-organization in various systems, including plants, nervous systems, slime mold, ant colonies, and cities. Learn how these systems make decisions without a central nervous system and the implications for our society.
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Plant can integrate information and make decisions without a central nervous system.
Stomata control entry of CO2 and exit of H2O from plant leaves Fig 10.21 Stomata
Plant can integrate information and make decisions without a central nervous system. Stomata aperture is affected by many stimuli: light, water, temperature, sugar content, circadian rhythm, CO2 levels…
Emergent properties- A complex system that arises from simple interactions of the individual components. So organisms or groups may have properties that none of the individual components possess. From: “Emergence” by Steven Johnson (2001)
Nerves allow us to perceive the environment while the brain integrates the incoming signals to determine an appropriate response. Fig 45.18 Response
Fig 45.3 Nervous systems can make complex calculations with cells that are on/off (1 or 0)
Fig 45.21 There is no boss in the brain. Nor directions in how to make one.
Slime mold aggregation Fig 29.9
Slime mold aggregation Fig 29.9
It has been known for some time that slime mold aggregation occurs via cAMP signaling
It was assumed that certain cells (pacemakers) signaled the others to aggregate
But, no one could find the pacemakers single cell
Each cell releases cAMP and responds to local conditions. Cells follow cAMP trail to aggregate with other cells. cAMP cAMP cAMP cAMP single cells cAMP cAMP cAMP cAMP cAMP cAMP cAMP
Each cell releases cAMP and responds to local conditions. Cells follow cAMP trail to aggregate with other cells… self-organizing cAMP cAMP cAMP cAMP single cells cAMP cAMP cAMP cAMP cAMP cAMP cAMP
Ant colonies: this is our concept of how an ant colony is organized.
The Queen is fed and lays eggs, but gives no orders. http://www.antstop.co.uk/nests/nest-static.jpg
Harvester ant wokers have four distinct tasks that they can perform outside the nest: foraging, patrolling, nest maintenance, and midden work
Each ant uses local information to determine what to do. Can do this without central command. With a few simple criteria, the plan comes together.
Interaction rate informs harvester ant task decisions Fig 2. Interaction rate informs harvester ant task decisions. M. Greene D. Gordon. Behavioral Ecology 18: 451-455
Patroller return rate increases about 30 min. before foragers leave nest Fig 2. Interaction rate informs harvester ant task decisions. M. Greene D. Gordon. Behavioral Ecology 18: 451-455
Adding beads (coated in patroller extract) at the correct rate can induce forager activity Fig 1. Interaction rate informs harvester ant task decisions. M. Greene D. Gordon. Behavioral Ecology 18: 451-455
Each ant uses local information to determine what to do. Can do this without central command. With a few simple criteria, the plan comes together.
Cities: Before zoning regulations were self-organizing. -Different zones: industrial, residential, markets, arts, etc.
Much of our society is based on emergent properties. Problems can arise as individuals try to manipulate the system.
Much of our society is based on emergent properties. Problems can arise as individuals try to manipulate the system. Google Bombs:Miserable failure directed searchers to the White House biography of G.W. Bush. http://news.bbc.co.uk/2/hi/americas/3298443.stm
…Stock Market prices set by what other people think will happen.
Much of our society is based on emergent properties: Democracy- as a group can we make better decisions than an individual?