Biological Classification

Biological Classification

Why classify?

Helps to understand things under the complexity of biological diversity

One and half million types of organism have been discovered on this planet and it has been estimated that there may be 10-100 million kinds of organisms.

How Classification Began?

Classification began By ancient people that observed nature and had a desire to organize the knowledge gained.

Classification- the grouping of objects based on similarities ex:: baseball cards, coins, shoes, etc

Ancient Chinese classification of dogsStray DogsThose have broken flower vaseResemble flies at a distance

Taxonomy•…the identification, naming, and classification of species

Has two parts

NomenclatureSystematics

Taxonomic hierarchy

Kingdom*Phylum (Introduced by Heackel in 19th century)Class*Order*Family*Genus*Species*

* Introduced by Linnaeus

What is species

Group of closely related interbreeding individual capable of producing fertile offspring

Mule

Types of classification

Artificial classificationBased on easily observed characters (Ancient Chinese

classification) Linnaeus classification of worms in Vermes (Earthworm,

Nematode, Snakes)

Natural classificationUse natural relation between organisms

Use diverse characters like anatomy, physiology, biochemistry etc.

Phylogenetic classificationBased on evolutionary relationship

Phenetic Classification – Numerical taxonomy

Aristotle(384-322 B.C.)Developed first widely accepted system of biological classification

According to his system, birds, bats, and flying insects are classified together even though they have little in common besides the ability to fly. As time passed, more organisms were discovered and some did not fit easily into Aristotle’s groups, but many centuries passed before Aristotle’s system was replaced

Animals (classified based on Habitat)

Living on landLiving in waterLiving in air

Plants (classified based on structure)

Herbs-- has (soft) stemsShrubs-- has several (woody) stemsTrees-- has one main (woody) trunk

Linnaeus’s system of binomial nomenclature Carolus Linnaeus (1707—1778)

Based on physical and structural similarities of organisms

As a result,, the groupings revealed the relationships of the organisms

Eventually, some biologists proposed that structural similarities reflect the evolutionary relationships of species

Binomial nomenclature system

Kingdom concept

Linnaeus(1735)

2 kingdoms

Haeckel(1866)

3 kingdoms

Chatton(1925)

2 groups

Copeland(1938)

4 kingdoms

Whittaker (1969)

5 kingdoms

Woese (1977,199

0)3

domains

Animalia Animalia

Eukaryote

Animalia Animalia

EukaryaVegetabilia

PlantaePlantae Plantae

Protoctista

Fungi

Protista

Protista Procaryote

Monera MoneraArchaea

Bacteria

Prokaryote lifestyle

unicellular: all alone

colony: forms a film

filamentous: forms a chain of cells

Prokaryote Feeding

Photosynthetic: energy from sunlight Disease-causing: feed on living

things Decomposers: feed on dead things

Eukaryotes are bigger and more complicated

Have organelles Have chromosomes can be multicellular

Organelles are membrane-bound cell parts Mini “organs” that

have unique structures and functions

Located in cytoplasm

Cell membrane delicate lipid

and protein skin around cytoplasm

found in all cells

Cell Structures

Nucleus a membrane-bound

sac evolved to store the cell’s chromosomes(DNA)

has pores: holes

Nucleolus inside nucleus location of

ribosome factory made or RNA

mitochondrion makes the

cell’s energy the more energy

the cell needs, the more mitochondria it has

Ribosomes build proteins from

amino acids in cytoplasm

may be free-floating, or

may be attached to ER

made of RNA

Endoplasmic reticulum may be smooth:

builds lipids and carbohydrates

may be rough: stores proteins made by attached ribosomes

Golgi Complex takes in sacs of

raw material from ER

sends out sacs containing finished cell products

Lysosomes sacs filled with

digestive enzymes digest worn out cell

parts digest food

absorbed by cell

Cytoskeleton

made of microtubules

found throughout cytoplasm

gives shape to cell & moves organelles around inside.

Structures found in plant cells Cell wall

very strong made of cellulose protects cell from

rupturing glued to other

cells next door

Vacuole huge water-

filled sac keeps cell

pressurized stores starch

Chloroplasts filled with

chlorophyll turn solar

energy into food energy

How are plant and animal cells different?

Structure Animal cells Plant cells

cell membrane Yes yes

nucleus Yes yes

nucleolus yes yes

ribosomes yes yes

ER yes yes

Golgi yes yes

centrioles yes no

cell wall no yes

mitochondria yes yes

cholorplasts no yes

One big vacuole no yes

cytoskeleton yes Yes

Virus

Bacteria

Pritista

Fungi

Plantae

Animelia