Diversity of Life
Chapter 4, Section 3
Evolution overview
• All life on earth began about 3.5 billion years
ago with organisms that were a single cell
• Then one billion years ago organisms that are
made of many cells appeared as a result of
evolution
• During evolution traits that do not help
organisms survive disappear while good traits
that help with survival remain
Classification
• As a result of evolution earth is populated by
many different organisms with different traits.
• We group these organisms according to their
similar characteristics
• Classification – grouping and naming of
organisms according to their evolutionary
relationships and shared characteristics
Tree of Life
Organisms are
classified into
based on:
1.Cell Type
a. Prokaryotes
b. Eukaryotes
Prokaryotic Cell
Eukaryotic Cell
2. Number of Cells
a. Unicellular
b. Multi-cellular
Unicellular
Multicellular
3. Cell Structure
4. Mode of Nutrition
a.Autotrophs
- Chemoautotrophs
- Photoautotrophs
b.Heterotrophs
3 Domains of Life
• Domain Bacteria
–Eubacteria
• Domain Archae
–Archaebacteria
• Domain Eukarya
–Protists, Fungi, Plantae, Animalia
Three Domain System
Domain Eukarya - includes organisms
composed of eukaryotic cells (plants, animals,
fungi, protists – 4 kingdoms)
Domain Bacteria - includes all prokaryotic cells
from Kingdom Eubacteria
Domain Archaea – prokaryotic cells, includes
only "ancient" bacteria, Archaebacteria (1
kingdom)
6 Kingdoms of Life
• Archaebacteria
• Eubacteria
• Protist
• Fungi
• Plant
• Animal
Kingdom Fungae
•Multicellular (most), some unicellular (baker's
yeast)
•Heterotrophic (mainly decomposers)
•Eukaryotic
Photos by
nutmeg66
Fungi
Play an important role in breaking down the bodies
of dead organisms.
Recycle matter, nutrients
Fungi are not the only decomposers (worms,
bacteria)
No decomposers = no life = no cycling of materials
= organisms won't have the building blocks to grow
and reproduce
Kingdom Protista
•Most are unicellular
•Can be heterotrophic (Ameba) or autotrophic
(Algae)
•Eukaryotes (all have nucleus)
•Most live in water
Photo of Ameba by PROYECTO
AGUA **/** WATER PROJECT
Kingdom Eubacteria & Kingdom
Archaebacteria
•Unicellular
•Can be autotrophic or heterotrophic
•Prokaryotes (do not have a nucleus)
Eubacteria = common bacteria
(E. coli, Salmonella)
Archaebacteria = “ancient
bacteria”, exist in extreme
environments
Archaea and Bacteria
• Archaea differ from bacteria in their genetics and
the makeup of their cell wall.
• Bacteria are microscopic, unicellular organisms that
usually have a cell wall and reproduce by cell
division.
• Unlike all other organisms, bacteria and archaea lack
nuclei.
• Bacteria and archaea live in every habitat on Earth,
from hot springs to the bodies of animals.
Bacteria and the Environment
• Some kinds of bacteria break down the remains
and wastes of other organisms and return the
nutrients to the soil.
• Others recycle nutrients, such as nitrogen and
phosphorus.
• Certain bacteria can convert nitrogen from the
air into a form that plants can use. This
conversion is important because nitrogen is the
main component of proteins and genetic
material.
Bacteria and the Environment
• Bacteria also allow many organisms, including
humans, to extract certain nutrients from
their food.
• The bacterium, Escherichia coli or E. coli, is
found in the intestines of humans and other
animals and helps digest food and release
vitamins that humans need.
Kingdom Plantae
• Multicellular
• Autotrophic
• Eukaryotic
• Cannot move
(due to cell walls)
Plants
• Mosses – example of plants with no vascular
tissue (can not transport water inside the
plant) – live near water or in humid areas,
can't grow tall
• Vascular Plants – transport water fro roots all
the way to the top of the plant – can grow tall,
no need to be near water
Vascular Plants
• Gymnosperms – cone bearing plants – naked
seed – seeds are not enclosed
• Angiosperms – flowering plants – greatest
number of plants on Earth – seeds are
enclosed in a ........ fruit; flower serves to
attract pollinators
Kingdom Animalia
Photo by Tambako the
Jaguar
•Multicellular
•Heterotrophic
•Most can move
•Examples: birds,
insects, worms,
mammals, reptiles,
humans, anemones
Photo by Eduardo Amorim
Animals
• Invertebrates are animals that do not have
backbones (insects, squid, horseshoe crab).
• Vertebrates are animals that have a backbone,
and includes mammals, birds, reptiles,
amphibians, and fish. Only Birds and
mammals are warm-blooded.