Diversity of Life

Exploring the vast array of living organisms on Earth today and in the

past

VIII. Classification

A. Taxonomy - science of classifyingOrganisms grouped into taxa

1. Linnaeus - developed a system of classifying living things

2. Five-Kingdom Classification systema. Kingdom

i. Animaliaii. Plantaeiii. Fungiiv. Protistav. Monera

Classification

2. Five Kingdom Classification systema. Kingdomb. Phylumc. Classd. Ordere. Familyf. Genusg. Species

3. Binomial nomenclaturea. Two word naming systemb. Scientific name - Genus species

Example: Homo sapiens

Classification

B. A closer look at the kingdoms1. Monera - bacteria, unicellular, prokaryotic2. Protista - “catchall kingdom”, unicellular and some

multicellular eukaryotes that do not belong to other kingdoms

3. Fungi - eukaryotic, heterotrophic, cell walls composed of chitin

4. Plantae - eukaryotic, multicellular, autotrophic, cell walls composed of cellulose

5. Animalia - eukaryotic, multicellular, heterotrophic, no cell walls

Classification

C. Three domain system is being constructed

1. Bacteria

2. Archae

3. Eukarya

5 Kingdom System Vs. 3 Domain System

Classification

D. Classification as it relates to evolution1. Organisms are grouped according to physical

characteristics and evolutionary relationships

2. Not all similar looking organisms belong in the same group

a. Convergent evolution results in the formation of analogous structures

b. Example - sharks and dolphins have similar characteristics, but they do not share a common ancestor

Origin of Life on Earth

D. Theories on the origin of life1. Spontaneous generation - life arises from nonlife

a. Needham - supported theoryb. Redi- questioned theory with experiments involving meatc. Spallanzani - disproved Needham’s experimentsd. Pasteur - disproved the theory of spontaneous generationhttp://www.kent.k12.wa.us/staff/TimLynch/sci_class/chap01/spontaneous.html

2. Extra-terrestrial3. Organic soup - cells developed from the materials present

in Earth’s early atmosphere a. Miller and Urey experiment simulated how life could have begunb. Ammonia, water, hydrogen, and methane with a spark of energy

(lightning) formed organic matter (amino acids,etc.)

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Origin of Life on Earth

E. Evolution of life1. First cells were prokaryotic

2. Endosymbiosis results in formation of first eukaryotic cells (Protista)

3. Multicellular organisms develop (Fungi, Plantae, Animalia)