Transcript Living things are made of units called cells.

Chapter 1
A View of Life
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I. How to Define Life
1. Living things are made of units called
cells.
All living things are made of one or more cells.
Cells are made of molecules that contain
atoms.
Many microorganisms consist of only a single
cell. Animals, plants, and fungi are almost
all multi-cellular.
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 2. Living Things Reproduce.
Reproduction is the ability of an
organism to copy itself or make new organisms
like itself.
– Bacteria, protozoans, etc. simply split into two.
– Multicellular organisms may pair sperm with
egg; resulting in an immature individual, which
develops to become the adult.
– Flies produce flies, dogs produce dogs, roses
produce roses.
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3. Living things are based
on a universal genetic code.
– Organisms develop as result of blueprint of
instructions encoded in their genes.
– Genes are made of long molecules of DNA that
specify how the organism is ordered.
– Mutations can occur EX Sickle cell anemia
 Heredity= the passing of traits/genes from
parent to offspring.
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4. Living things grow and
develop.
 Flies begin life as eggs, then become
maggots, and then become adult flies.
 An oak tree begins life as an acorn in the
ground, germinates becoming a seedling,
and then grows and develops into the
mighty oak tree.
 You started life as an embryo in the womb,
were born as a young baby, and have grown
into a teenager/young adult.
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5. Living Things Acquire
Materials and Energy.
Metabolism is the sum of all chemical
reactions that occur in a cell. Using energy!!
– Ultimate source of energy for nearly all life on
earth is the sun through photosynthesis.
– Using materials/food organisms obtain
(consume/absorb) from the environment or
produce themselves, organisms can build
molecules they put into growth and development,
and this also takes energy to build something.
Organisms also use/release energy when they
break molecules down, this too is part of
metabolism.
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 6. Living Things Respond to their
Environment. This ability to respond
helps organism survive.
– Responses to environment altogether constitute
behavior of organism.
– Example: The leaves and stems of plants grow
towards light.
 7. Living Things Maintain a Stable
Internal Environment.
– Homeostasis:Organisms must remain
homeostatic or keep themselves stable inside
their cells and tissues. Temperature, moisture
level, acidity, etc. are all factors that need to be
maintained by physiology and behavior. EX.
Sweating, when too hot, release heat and cools
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 8. Taken as a group, living things
change over time, they evolve
 Natural selection is the mechanism by
which species become modified over time.
• A species is a group of interbreeding
individuals.
• In natural selection, members may inherit a
genetic change that makes them better suited to
a particular environment.(Darwin)
• Example: Plants that live in the desert survive
because they have become adapted to the dry
conditions of the desert.
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Biological Organization
All the same type of organisms (species)
inhabiting an area at the same time make up a
population.
The populations inhabiting an area at the same
time make up a community.
– A community plus its physical environment
constitutes an ecosystem.
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