- Domains and Kingdoms
Three Domains of Life
• In the three-domain system of classifications,
all known organisms belong to one of three
domains–Bacteria, Archaea, or Eukarya.
-
Life Comes From
Life
• Francesco Redi
designed one of the
first controlled
experiments. In his
experiment, Redi
showed that flies do
not spontaneously
arise from decaying
meat.
- What Is Life?
Life Comes From Life
• Louis Pasteur’s
carefully
controlled
experiment
demonstrated that
bacteria arise only
from existing
bacteria.
What do all living things have in
Common?
All living things are made of cells
•
•
•
•
Unicellular- one cell
Multicellular- many celled
Eukaryotic- has a nucleus
Prokaryotic- no nucleus
All living things are organized.
• From as small as a molecule to as large as an
organism.
– atom, compound, cell, tissue, organ, organ
system, organism
• Organization depends on their function
All living things use energy?
• Metabolism----the chemical reactions of all
the energy intake and use
• People take chemical energy (food) and
change it in heat and mechanical energy
• Plants take light energy(sun) and change it
into chemical energy(food)
All living things maintain a stable
internal environment
• Homeostasis
• Examples:
– Sweating
– Shivering
– goosebumps
All living thing grow and develop
• Growing is getting more and more cells in
body
– As you get bigger you have more cells
• Development is when the cells become
specialized and have a particular job or
function….example of blood cells
• All is determined by the genetic code for life
All living things reproduce
• Sexual reproduction- require two cells and
creates a unique offspring
• Asexual reproduction- only requires one cell
that simply splits or makes a copy of them
selves
• Both occur in the human body
- Discovering Cells
Development of the Cell Theory
•The cell theory states the following:
• All living things are composed of cells.
• Cells are the basic units of structure and function in living things.
• All cells are produced from other cells.
- Discovering Cells
•how the work of Hooke, Leeuwenhoek,
Schleiden, Schwann, and Virchow contributed
to scientific understanding of cells.
Discovering Cells
Hooke sees cells in cork.
Leeuwenhoek sees many one-celled organisms.
Schleiden concludes that all plants are made of cells.
Schwann concludes that all animals (and all living things) are
made of cells.
Virchow proposes that new cells form only from cells that
already exist.