Characteristics of Living Things
What does it
mean to be
alive?
The Big Ideas…
• Made of Cells
• Reproduce (sexually or asexually)
Living things are made of units called cells
• The cell is the smallest part of
an organism that is considered
alive.
• Organisms can be unicellular
(one cell) or multicellular
(many cells)
Living things reproduce
• All living organisms come from
other living things.
• Sexual reproduction – two cells
from different parents.
• Asexual reproduction – Offspring is
created from a single parent.
The Big Ideas…
•
•
•
•
Made of Cells
Reproduce (sexually or asexually)
Have DNA (genetic information)
Grow & Develop
Living things have a universal genetic code (DNA)
• Directions for inherited traits
are included in an organisms
DNA
• Living things make copies of
themselves; to do so they pass
on genes.
• All organisms have the same
basic DNA structure.
Living things grow and develop
• Some organisms increase in size
(unicellular).
• Some organisms start as a single
cell that grows, divides into two
that stay connected and grows
again (multicellular).
The Big Ideas…
•
•
•
•
•
•
Made of Cells
Reproduce (sexually or asexually)
Have DNA (genetic information)
Grow & Develop
Need/Use Energy (metabolism)
Respond to Environment
Living things need and use materials for energy
(nutrient source)
• Nutrient source allows for chemical
reactions that take place in cells.
• Materials come from surrounding
environment.
• Metabolism is the combination of all
the chemical processes in an
organism that build up or break down
materials.
Living things respond to their environment
• Reaction to immediate changes or needs
(stimulus)
• Light, temperature, other organisms,
hunger
The Big Ideas…
•
•
•
•
•
•
•
•
Made of Cells
Reproduce (sexually or asexually)
Have DNA (genetic information)
Grow & Develop
Need/Use Energy (metabolism)
Respond to Environment
Maintain Homeostasis (constant internal environment)
Change Over Time (evolve)
Living things maintain an internal balance
• External conditions may change dramatically, but most organisms must
keep internal conditions relatively steady.
• Called homeostasis
• Connects with responding to our environment.
Evolution is the change in living things over time
• Adaptations are beneficial inherited traits
that are passed to future generations.
• Evolution can occur through natural selection
of adaptations.
• The genetic makeup of a population changes.
The Big Ideas…
•
•
•
•
•
•
•
•
•
•
Made of Cells
Reproduce (sexually or asexually)
Have DNA (genetic information)
Grow & Develop
Need/Use Energy (metabolism)
Respond to Environment
Maintain Homeostasis (constant internal environment)
Change Over Time (evolve)
Form Systems & Have Systems (related parts)
Structure & Function are Related
All levels of life have systems of related parts
• A cell is a system of
chemicals and processes.
• A body system includes
organs that interact.
• An ecosystem includes
living and nonliving things
that interact.
Structure determines function.
• Cells have a different structures
and functions in complex
organisms. (specialization)
• Different species have different
anatomical structures with
different functions.
…and now for Marty’s story.