emester Exam #4 W 5/6 in class (don’t forget your cheat sheet) Class on F 5/8 will be a review for the optional FINAL EXAM Final T 5/19 at 9am-noon

Two ways to think about the world: atoms molecules organelles cells tissues organs systems organisms environment Reductionism holism

Emergent properties- properties of an organism or group that none of the individual components possess. From: “Emergence” by Steven Johnson (2001)

Plant can integrate information and make decisions without a central nervous system.

Fig 37.4 Water travels from ground out through stomata via xylem

Stomata control entry of CO 2 and exit of H 2 O from plant leaves Stomata Fig 10.21

Stomata on the underside of a leaf

Stomata aperture is affected by many stimuli: light, water, temperature, sugar content, circadian rhythm, CO 2 levels… Plant can integrate information and make decisions without a central nervous system.

Fig Nerves allow us to perceive the environment while the brain integrates the incoming signals to determine an appropriate response. Response

Fig 45.3 Nervous systems can make complex calculations with cells that are on/off (1 or 0)

Fig 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. single cells cAMP

Each cell releases cAMP and responds to local conditions. Cells follow cAMP trail to aggregate with other cells… self-organizing single cells cAMP

Slime molds can learn. The plasmodium can figure out the shortest path through a maze.

Ant colonies: this is our concept of how an ant colony is organized.

The Queen is fed and lays eggs, but gives no orders.

So who is in charge?

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.

Fig 2. Interaction rate informs harvester ant task decisions. M. Greene D. Gordon. Behavioral Ecology 18: Interaction rate informs harvester ant task decisions

Fig 2. Interaction rate informs harvester ant task decisions. M. Greene D. Gordon. Behavioral Ecology 18: Patroller return rate increases about 30 min. before foragers leave nest

Fig 1. Interaction rate informs harvester ant task decisions. M. Greene D. Gordon. Behavioral Ecology 18: Adding beads (coated in patroller extract) at the correct rate can induce forager activity

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.

Not everyone uses the same criteria to make decisions...

…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?

emester Exam #4 W 5/6 in class (don’t forget your cheat sheet) Class on F 5/8 will be a review for the optional FINAL EXAM Final T 5/19 at 9am-noon