Major Events in the History of Earth
Cenozoic
Humans
Land plants
Origin of solar
system and
Earth
Animals
4
1
Proterozoic
eon
Multicellular
eukaryotes
2
Archaean
eon
3
Prokaryotes
Single-celled
eukaryotes
Atmospheric
oxygen
Classification systems
5 Kingdom system
1. Monera
2.
3.
4.
5.
Protista
Fungi
Animalia
Plantae
3 Domain system
1. Bacteria
2. Archaea
3. Eukarya
Prokaryotes vs. eukaryotes
Unicellular vs. multicellular
autotrophic vs. heterotrophic
Symbiotic relationships between any two organisms:
1. commensalism one organism benefits and the other is
unaffected
2. mutualism both organisms benefit
3. parasitism one organism benefits and the other one is
harmed.
Bacteria
-
Very diverse
Unicellular prokaryotes (lack a nucleus)
Three basic shapes: Bacillus, coccus, spirillum
Some are filamentous
Have a complex cell wall
Some autotrophic (Phototrophic or chemotrophic) others
heterotrophic
- Found everywhere. Many live as symbionts in other
organisms
Protista
Bottom–dwellers: attached or creeping
Drift passively near the water surface (plankton)
Phytoplankton
- photosynthetic (planktonic algae and
cyanobacteria) form the foundation of most
marine and freshwater food webs
- free–living species
Zooplankton- Protozoa
- heterotrophic
Eukaryotic- Protista
• Majority unicellular
• Multicellular – seaweed,
kelp
• Cell wall present or
absent
• Vary in cell wall
composition:
o Silica (glass)
o Calcium carbonate
(limestone)
o Cellulose
• Vary in energy source
o Photosynthetic –
Euglena
o Heterotrophic –
Amoeba &
Paramecium
Parasitic pathogens:
• Giardia
• Malaria
Amoeba
Euglena
Paramecium
Diatoms
Volvox
Early aquatic photosynthetic organisms :
- Prokaryotic Cyanobacteria
- Eukaryotic algae
Unicellular Chlamydomonas
Multicellular Spirogyra
Cyanobacteria filamentous photosynthetic
prokaryote
Spirogyra filamentous photosynthetic algae, pond
scum
Fungi
Eukaryotic decomposers (heterotrophic) found in many
environments
- saltwater or fresh water
- on land
- cold or warm temperatures
Serve as a valuable ecological function by processing dead
organic matter
Unicellular (yeast)
Multicellular filamentous (mold)
Parasitic pathogens:
Fungi evolved from an aquatic, flagellated ancestor
A fungus usually consists of a mass of threadlike
hyphae called a mycelium
Hypha
Mycelium
Fungi absorb food after digesting it outside
their bodies and absorb the nutrients
Fungal life cycles include asexual and sexual
stages
ASEXUAL
- Haploid spores give rise to multi-cellular
filamentous haploid hyphae by mitosis
- The haploid hyphae are made of mating
types
Fungal groups differ in their life cycles and
reproductive structures
Key
Haploid (n)
Zygosporangium (n + n)
Heterokaryotic (n + n)
Diploid (2n)
Mycelia of
Cells fuse
different
mating types
2
3
Fusion of
nuclei
1
Meiosis
Young
zygosporangium
(heterokaryotic)
4
Sporangium
Spores
(n)
SEXUAL in fruiting bodies
- Fusion of haploid hyphae produces a
stage containing nuclei from two parents
heterokaryotic hyphae
- Nuclei fuse and undergo meiosis which
produces haploid spores
Fungal groups have characteristic reproductive
structures
Key
Haploid (n)
Heterokaryotic (n + n)
3 Diploid nuclei
Fusion of
nuclei
Meiosis
Diploid (2n)
4 Spores
released
Basidia
Spores (n)
Mushroom
5 Germination of spores
and growth of mycelia
2 Growth of
heterokaryotic mycelium 1 Fusion of two hyphae
of different mating types
Lichens consist of fungi living mutualistically
with photosynthetic organisms
Fungal
hyphae
Algal
cell
Colorized SEM 1,000 ×
Lichens consist of algae or cyanobacteria within a
fungal network
Early land photosynthetic organisms
Lichens- symbionts of a fungus and a
photosynthetic organism either a cyanobacteria or
an algae
The photosynthetic algae or bacteria provide
organic compounds which the fungus can use and
the fungus provides support and protection for
either the algae or the bacteria.
Lichens can be found in the harshest of
environments on rocks