Taxonomy and Classifications - ACT Biology

Taxonomy

Definition: Science of grouping animals and plants based on appearance and relationships.

Purpose: Organize and study Earth's diverse living things.

Domain Bacteria

Characteristics: Prokaryotic, unicellular, thick cell walls with peptidoglycan.

Functions: Some are decomposers or photosynthetic

Gene Transfer: Horizontal gene transfer through conjugation, transformation, and transduction.

Domain Archaea

Characteristics: Unicellular, prokaryotic, thrives in extreme conditions.

Types: Extremophiles, halophiles, thermophiles.

Domain Eukarya

Multicellular, membrane-bound organelles, nucleus.

Kingdom Protista

Mostly unicellular, various modes of movement.

Kingdom Fungi

Heterotrophic, decomposers, chitin cell wall.

Kingdom Animalia

Multicellular, heterotrophic eukaryotes.

Germ Layers

Definition: Primary cell layers in embryonic development.

Types: Ectoderm (skin, nervous system), Mesoderm (muscles, bones), Endoderm (viscera, digestive system).

Triploblast

Organism with three germ layers.

Diploblast

Organism with two germ layers.

Body Symmetry

Types: Radial (e.g., sea anemones), Bilateral (e.g., humans).

Importance: Defines organism structure and function.

Body Cavity

Coelom: Fluid-filled body cavity in higher animals.

Types: Acoelomate, Pseudocoelomate, Coelomate.

Porifera (Sponges)

Simple, aquatic, sessile, filter nutrients.

Cnidaria (Cnidarians)

Jellyfish, corals, radial symmetry, diploblast.

Platyhelminthes (Flatworms)

Bilateral symmetry, triploblast, hydrostatic skeleton.

Annelida (Annelids)

Segmented worms, closed circulatory system.

Mollusca (Mollusks)

Bilateral symmetry, open circulatory system, gills.

Arthropoda (Arthropods)

Largest phylum, jointed appendages, chitinous exoskeleton.

Nematoda (Roundworms)

Bilateral, non-segmented, found in various environments.

Echinodermata (Echinoderms)

Radial symmetry, sessile, endoskeleton, tube feet.

Chordata (Chordates)

Vertebrates, classified into fish, amphibians, reptiles, birds, mammals.

Monotremes

Egg-laying, lack nipples (e.g., platypus).

Marsupials

Birth to undeveloped young, pouch (e.g., kangaroos).

Placentals

Developed live young, placenta (e.g., humans).

Bacteria

Microorganisms
Prokaryotes, unicellular, peptidoglycan cell wall.

Reproduction: Binary fission.

Fungi

Microorganisms
Multicellular eukaryotes, chitin cell wall.

Function: Decomposers.

Protists

Microorganisms
Eukaryotic, unicellular/multicellular.

Example: Malaria-causing organisms

Viruses

Microorganisms
Non-living, genetic material in protein coat.

Reproduction: Lytic and lysogenic cycles.

Virus Life Cycles

Lytic Cycle: Virus makes new viruses, host cell rupture.

Lysogenic Cycle: Viral genetic material hides, can switch to lytic later.

Mammals Classification

• Monotremes

• Marsupials

• Placentals

Extremophiles

Lives in extreme environments such as pools with high concentrations of methane gas

Halophiles

Lives in environments with high salt concentrations

Thermophiles

Lives in environments elevated temperature

Paramecium Movement

Propelled by cilia (hair-like structures).

Amoeba Movement

Uses pseudopods (temporary extensions).

Euglena Movement

Flagellum (whip-like tail).