The document discusses the classification of living organisms, emphasizing the importance of grouping based on structural and evolutionary similarities. It introduces phycology, the study of algae, detailing its characteristics, diversity, reproduction methods, and ecological roles. Algae, primarily photosynthetic and aquatic, vary in size and complexity, lacking true roots, stems, and leaves, making them distinct from higher plants.

1. Classification
 grouping of different types of organisms based upon
similarities in structure and evolutionary relationships
Why classify?
In order to more easily study the unity and diversity of
living organisms in an organized manner, biologists classify
organisms
This means that they group organisms together based
on their common characteristics
 Physical structure is often the primary basis for
biological classification

2. Early classification
Animals & Plants
With the discovery of the MICROSCOPE in the 1600’s
many new organisms were discovered
This was the basis for the change in the classification
system

3. MODERN CLASSIFICATION SYSTEM
• KINGDOM
• PHYLLUM
• CLASS
• ORDER
• FAMILY
• GENUS
• SPECIES (the smallest)
Taxonomic rankings:

4. Five kingdom of life
 Kingdom Monera: bacteria and blue green
algae
 Kingdom Protesta: protozoans and algae
 Kingdom Fungi: funguses, molds, yeasts etc
 Kingdom Animalia: animals
 Kingdom Plantae: bryophytes, pteridophytes,
gymnosperms and angiosperms

5. BIONOMIAL NOMENCLATURE
• Carolus Linneaus devised binomial nomenclature
• (2 names in Latin) Genus-Species
– Both have to be printed in italics or underlined
– -Genus is ALWAYS capitalized
– ex. scientific name of humans ..... Homo sapiens
– Homo is the genus name .... sapiens is the
species name

6. Introduction about phycology
 Phycology or algology: is the study of the algae.
 The word phycology is derived from the two Greek
word:
 Phykos, which means seaweed or algae
 Logous: study
 This discipline deals with the morphology, taxonomy,
phylogeny, biology, and ecology of algae in all
ecosystems
 The scientists who study about algae are called
phycologists
Algae are a diverse group of mostly photosynthetic
organisms that share a few characteristics, but which lack
the structural complexity associated with higher plants

7. Introduction con’t
 Cell types: prokaryotic-nuclei and other organelles
lack double membranes
 eukaryotic -cells have organelles with double
membranes.
 And it compost of either unicellular or multicellular
cells.
 Reproduction: reproduce through asexually and
sexually.
• The algae exhibit an immense range of size,
structural complexity, and morphology.
• Size: varies from micrometers (e.g., the unicell
Chlorella) to meters (e.g., the giant kelp Macrocystis).

8. • Structural complexity: varies from undifferentiated single cells to highly
differentiated multicellular kelps, which may even have cells specialized
for translocation of photosynthates.
• Morphology varies from unicells and colonies to finely divided
filaments, to blades with stipes and holdfasts.
• Plant body is thallous and the vegetative structures of multicellular
algae has:
 Thallus: Lacks conductive tissue.
 Holdfasts: Anchor alga to rock.
 Stipes: Hollow, stem-like structures. Does not support weight.
 Blades: Leaf-like structures.
 Pneumatocyst: Floating, gas-filled bladder.
Diversity: There are millions of algal species
 Most are useful, A few produce toxins that are harmful to
humans

9. DISTINCTIVE CHARACTERSTICS OF ALGAE
 Algae are chlorophyll bearing organisms which are thalloid
(having no true roots, stems and leaves)
• As result, thallophytes (plants lacking roots, stems, and leaves)
 The thallus shows little differentiation of true tissues
 No xylem or phloem
 Even the complex thalli lack vascular tissue and epidermis with
stomata.
 The sex organ are unicellular (one celled), when multicellular
(brown algae) each cell is fertile and there is no jacket of sterile
cells.
 No embryo formation after gametic union
 Both generations when represented in their life cycle are
independent. There are no algae with a sporophyte parasitic on
the gametophyte plant.
 Except a few, all algae are predominantly aquatic.

10. Ecology of algae
On the bases of habitat they may be:
• 1. Aquatic algae: most commonly occur in water: fresh
water, marine, or brackish.
• Need water for support, reproduction, and nutrition.
Absorb nutrients from the water over entire surface.
• 2. Terrestrial algae-growing:
• in snow mountains
• on bare rocks with lichen,
• in and on soils parts.
• 3. Algae of unusual habitats: some algae also occur in
uncommon habitats-on other algae or aquatic plants,
grow on animals like snails fishes

11. Ecol. Con’t
• Algae illustrate the importance of photosynthesis
to the Earth’s ecology
• The primary photo synthetic organisms in
freshwater and marine food chains.
• As a food source for zooplankton and filter
feeding shellfish, the algae are an extremely
important group.

12. Comparison of Algae and Plant Structure