What is life?
Characteristics
of Living Things.
Mr. Hanczyc
8 Characteristics of Living Things
1.
2.
3.
4.
5.
6.
7.
8.
Composed of cells
Respond to external stimuli
Obtain and use energy
Grow and develop
Reproduce
Maintain stable internal environment
Change over time: Adapt and evolve
Based on a universal genetic code
1. Composed of cells
 Organisms
are composed of one or more
cells
 Cells are the basic unit of life – they can
grow, respond to stimuli, and reproduce
2. Respond to external stimuli
 Organisms
detect and respond to stimuli
from their environment
 Stimulus – a signal to which an organism
responds
3. Obtain and use energy
 All
organisms must take in energy to grow,
develop, and reproduce.
 Metabolism - combination of chemical
reactions that release energy in food.
 Endocytosis – a process that cells use to
absorb substances by engulfing
3. Obtain and use energy

Endocytosis (ex. amoeba vs. paramecia)
4. Grow and develop
 Every
organism has a pattern of growth
and development.
 Humans - A single fertilized egg divides
again and again into multiple cells.

Cells differentiate to form specialized cells
ex. muscle cells, neurons, blood cells
4. Grow and develop
5. Reproduce
 All
organisms reproduce to form similar
organisms.


asexual reproduction – single organism
divides to produce identical new organisms
sexual reproduction – cells from two
organisms unite to form the first cell of a
new organism
5. Reproduce
5,000,000,000,000,000,000,000
6. Maintain a stable internal
environment
 Homeostasis
– process by which
organisms keep their internal environment
stable, even when external conditions
change rapidly.
 ex.
constant body temperature in humans
7. Change: Adapt and Evolve
 Adaptations
are traits that provide an
advantage for organisms in a certain
environment.
 Organisms adapt to their environment as
species through natural selection.
 Evolutionary change occurs on the
population level and links organisms to a
common ancestor 3.5 BYA.
8. Universal Genetic Code
 Offspring
inherit traits from their parents.
 DNA / RNA provide mechanism of
inheritance.
 Asexual Reproduction – identical offspring
 Sexual Reproduction – genetic variation
8. Universal Genetic Code
References
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

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
PA Standards – 3.1.B.A1, 3.3.10
Miller and Levine. Biology. pp. 17-25. 2014
Amoeba
Videohttps://www.youtube.com/watch?v=jNhj07qa-A
Sensitive Plant Video
https://www.youtube.com/watch?v=DF-b6TsO1DM
Acorn Video
https://www.youtube.com/watch?v=4BtKAkP5xOk
Bacteria Growth Video
https://www.youtube.com/watch?v=gEwzDydciWc