In This Lesson:
Characteristics of
Life
(Lesson 3 of 4)
Today is Friday (!),
th
September 4 , 2015
Pre-Class:
What makes something alive? Can you come up with a
list of qualities a living thing must have in order to be
alive? Be prepared for an informal discussion.
Having trouble? Try this:
Convince me that a rock is not alive.
Today’s Agenda
• Get a life…
• …characteristics list.
• Where is this in my book?
– Academic: P. 17 and following…
– Honors: P. 4-5
By the end of this lesson…
• You should be able to assess the living or nonliving nature of an object based on set criteria.
Introducing…
• Let’s do two introductory activity-like things:
– Das Rad
– Identifying Life Activity
Das Rad
• German Short Film
• Things to think about:
– What’s alive in the film? What is just “fictionally
alive?”
– What’s not alive in the film?
– What’s the difference?
Being alive…
• There’s a lot of weird stuff out there.
• Biologists have settled on eight characteristics
that something must have in order to be
considered alive.
• Important:
– It must have all eight.
– Only seven? Too bad. Not alive.
#1: Made of Cells
• All living things are made of cells.
– Unicellular beings have only one cell.
– Multicellular beings have more than one cell.
#2: Can Reproduce
• Reproduction can be asexual (one parent) or
sexual (two parents).
#3: Has Genetic Code
• DNA (or sometimes other forms) is found in
almost every cell and ultimately controls your
traits.
http://www-nmr.cabm.rutgers.edu/photogallery/proteins/gif/dna.gif
#4: Grow and Develop
• All living things develop and grow during their
lives (at least part of ‘em).
• That’s why we don’t look like big overgrown
babies. We look like adults…most of us…
http://www.coachr.org/growth2.jpg
#5: Need Materials/Energy
• All living things need some kind of food or
energy source.
http://energybusinessdaily.com/wp-content/uploads/2009/10/Photosynthesis.jpg
#6: Respond to Stimuli
• Organisms respond to stimuli (signals either
from their bodies or the environment).
– Internal Stimuli – from within the organism.
– External Stimuli – from outside the organism.
http://man-over-board.com/wp-content/uploads/2009/10/baseball-head.jpg
#7: Homeostasis
• Homeostasis is the process of maintaining
internal balance.
– Body acidity, oxygen levels, and temperature (even if
you’re ectothermic) must all be kept in balance.
http://www.reptilechannel.com/images/blog/beardie-bask-500.jpg
Homeostasis Example
• Humboldt penguins
are not cold-weather
birds.
• To deal with warm
temperatures in their
native South America,
the bare skin near
their beaks turns red.
– The redness is due to
increased blood flow
to the area, allowing
the outside air to cool
them.
http://twearth.com/images/penguins/humboldt-penguin-79da1c624ed78b95a6eb3c2a1fc041e2.jpg
#8: Evolve
• Anything that’s considered alive has to have
evolved at some point.
http://images.wikia.com/fossil/images/7/79/Geological_time_spiral.png