Copy of Classification

Classification

• A process of grouping organisms by similarities.

Prokaryotes vs. Eukaryotes

Prokaryotic Cell

• Components:

  • Nucleoid

  • Pili

  • Cytoplasm

  • Cell wall

  • Plasma membrane

  • Flagella

Eukaryotic Cell

• Components:

  • Nucleus

  • Nucleolus

  • Golgi apparatus

  • Cytoskeleton

  • Plasma membrane

  • Endoplasmic reticulum

  • Vesicle

Autotroph vs. Heterotroph

Autotroph (Producers)

• Produce their own food for energy.

• Methods include photosynthesis or chemosynthesis.

• Examples include plants, algae, some bacteria.

Heterotroph (Consumers)

• Obtain energy by eating other organisms.

• Examples include animals, fungi, most bacteria.

Three Domains of Life

1. Bacteria

2. Archaea

3. Eukarya

   • Sub-divided into:

     • Protista

     • Plantae

     • Fungi

     • Animalia

Questions about Three Domains of Life

1. Which domain includes animals, plants, protists, and fungi?

   • Answer: Eukarya; contains complex cells including multicellular organisms.

2. How many domains consist solely of prokaryotes?

   • Answer: Two (Bacteria and Archaea).

Endosymbiotic Theory

• Explains the origin of eukaryotic cells.

• Proposes that early prokaryotes were engulfed by larger cells, leading to a mutually beneficial relationship.

• Engulfed prokaryotic cells evolved into organelles (e.g., chloroplasts and mitochondria).

Overview of Endosymbiosis Process

• Key Players:

  • Ancestral Prokaryote

  • Cyanobacterium (became chloroplast)

  • Aerobic bacterium (became mitochondrion)

Evidence for Endosymbiosis

• Supporting Features:

  • Membranes: Double membrane bound

  • Antibiotics: Susceptibility patterns

  • Division: Mode of replication resembles bacteria

  • DNA: Presence of circular DNA similar to bacterial DNA

  • Ribosomes: Size similar to those in prokaryotes

Mnemonic for Endosymbiotic Evidence

• MAD DR:

  • Chloroplast

  • Mitochondrial Evidence

Taxonomy

• Branch of biology that groups and names organisms.

• Example Classification:

  • Species: Canis lupus

  • Genus: Canis

  • Family: Canidae

  • Order: Carnivora

  • Class: Mammalia

  • Phylum: Chordata

  • Kingdom: Animalia

8 Levels of Classification

1. Domain

2. Kingdom

3. Phylum

4. Class

5. Order

6. Family

7. Genus

8. Species

• Progression from largest (Domain) to smallest group (Species).

Organisms Classified Today Using:

• Structural Similarities: Homologous parts

• Biochemistry: DNA and proteins

• Embryology: Developing embryos

• Breeding Behavior: Courtship patterns

• Geographic Distribution: Location and environmental barriers

Archaebacteria

• Characteristics:

  • Prokaryotic

  • Unicellular

  • Nutrition: Heterotrophs and autotrophs

  • Cell wall: No peptidoglycan

  • Mobility: Flagella present

Types of Archaebacteria

1. Thermophiles: Live in high-temperature environments

2. Halophiles: Salt-loving bacteria

3. Extreme Acidophiles: Thrive in acidic conditions

Eubacteria

• Characteristics:

  • Prokaryotic

  • Unicellular

  • Nutrition: Heterotrophs and autotrophs

  • Cell wall: Peptidoglycan present

  • Mobility: Can be mobile (flagella or cilia) or non-mobile

Reproduction

• Binary fission (asexual) and conjugation (sexual).

• Some are pathogenic, but many are harmless.

Eukaryotes

• Characteristics:

  • Nucleus and membrane-bound organelles

  • Unicellular or multicellular

  • Nutrition: Heterotrophs and autotrophs

  • Cell walls (in some) made of cellulose (plants)

  • Can reproduce asexually or sexually

Divisions of Eukarya

Protista

• Characteristics:

  • Some unicellular, most multicellular

  • Nutrition: Heterotrophs

  • Types include paramecium, volvox, algae

Fungi

• Characteristics:

  • Multicellular (mostly)

  • Nutrition: Heterotrophs and decomposers

  • Cell wall made of chitin

  • Usually non-mobile

  • Reproduction via spores

Plantae

• Characteristics:

  • Multicellular

  • Nutrition: Autotrophs

  • Cell wall made of cellulose

  • Reproductive structures in pollen

  • Organized into tissues, organs, and systems

Animalia

• Characteristics:

  • Multicellular

  • Nutrition: Heterotrophs

  • No cell wall (membrane only)

  • Almost all move

  • Reproduction: Mostly sexual

  • Organized into tissues, organs, and systems

Kingdoms Summary

• Animalia

• Archaebacteria

• Eubacteria

• Protista

• Fungi

• Plantae

• Phylum categories in Animalia include:

  • Chordata

  • Porifera

  • Cnidaria

  • Platyhelminthes

  • Nematoda

  • Annelida

  • Mollusca

  • Arthropoda

  • Echinodermata

Conclusion

• Classification is crucial for understanding and organizing life forms across various domains, emphasizing evolutionary relationships and adaptations!