Classifying Life's Diversity: Study Notes

• Study notes on classifying life's diversity, viruses, bacteria, protists, and multicellular organisms

Classifying Life's Diversity

• Morphological species concept relies on appearance and physical traits for species identification
• Biological species concept uses the ability to mate and produce fertile offspring to define a species
• Phylogenetic species concept defines species based on shared ancestry and evolutionary divergence
• Binomial nomenclature is a two-name system including genus and species for classifying organisms
• Taxonomy is the science of classifying organisms

Species Relationships

• Anatomical evidence uses bone structure and physical traits
• Physiological evidence studies internal processes like metabolism
• DNA evidence analyzes genetic similarities
• Phylogenetic trees are diagrams depicting evolutionary relationships between species

Kingdoms and Domains

• The three domains of life are Bacteria, Archaea, and Eukarya
• Bacteria and Archaea are prokaryotic domains
• Eukarya is the eukaryotic domain
• There are six kingdoms: Eubacteria, Archaebacteria, Protists, Fungi, Plantae, and Animalia
• Prokaryotic cells lack a nucleus
• Eukaryotic cells possess a nucleus and complex organelles
• Dichotomous keys help identify organisms through a series of choices

Biodiversity

• Species diversity measures the variety of species in an ecosystem
• Genetic diversity reflects the variety of genes within a species
• Ecosystem diversity represents the variety of ecosystems in a region

Viruses

• Viruses are not considered living organisms because they cannot reproduce independently, grow, develop, or produce energy
• Viruses are classified by capsid shape and size, and by the diseases they cause

Viral Reproduction: Lytic Cycle

• Injects DNA into host cell
• Replicates rapidly using the host
• Destroys the host cell (lysis)
• Releases new viruses to infect more cells

Viral Reproduction: Lysogenic Cycle

• Viral DNA integrates into the host cell's genetic material
• Viral genetic material replicates along with the host cell DNA
• Host cell functions normally
• Can enter the lytic cycle under certain triggers

Bacterial Shapes and Arrangements

• Cocci are spherical-shaped bacteria
• Bacilli are rod-shaped bacteria
• Spirilla are spiral-shaped bacteria
• Diplo indicates pairs of bacteria
• Staphylo indicates clustered bacteria
• Strepto indicates chains of bacteria

Bacterial Habitats

• Thermophiles thrive in high-temperature environments
• Acidophiles thrive in acidic environments
• Halophiles thrive in high-salt environments

Bacterial Reproduction: Binary Fission (Asexual)

• Cell elongates and DNA replicates
• Cell wall and plasma membrane start to divide
• DNA copies move to opposite sides
• Cell separates into two identical cells

Bacterial Reproduction: Conjugation (Sexual)

• A resistant bacterium forms a bridge to a sensitive bacterium
• Copies of resistance genes are transferred through the conjugation bridge
• Sensitive bacterium gains resistance

Identifying Bacteria

• Gram-positive bacteria have a thick peptidoglycan layer and stain purple
• Gram-negative bacteria have a thin peptidoglycan layer and stain pink

Eukaryotic Evolution: Endosymbiotic Theory

• Complex eukaryotic cells evolved from simpler prokaryotic cells through endosymbiosis
• Smaller prokaryotic cells were engulfed by larger ones, forming a symbiotic relationship
• Mitochondria and chloroplasts provide evidence for endosymbiosis
• Mitochondria releases energy from sugar
• Chloroplasts use sunlight to make sugar through photosynthesis
• Inward folding of the cell membrane is thought to have created the ER and Golgi apparatus

Protists

• Animal-like protists (protozoa) are heterotrophs classified by movement (pseudopods, flagella, cilia)
• Plant-like protists perform photosynthesis
• Fungus-like protists absorb nutrients from other organisms

Protist Structures

• Paramecium move using cilia and have a nucleus and vacuoles
• Amoeba move using pseudopodia (false feet)

Protist Locomotion

• Cilia are hair-like structures used for movement (e.g., paramecium)
• Flagella are whip-like tails used for movement (e.g., euglena)
• Pseudopodia are false feet used for movement (e.g., amoeba)

Terrestrial Plant Evolution

• Terrestrial plants evolved from algae over millions of years
• Algae can be unicellular or multicellular
• Multicellular algae ("seaweeds") are classified into brown, red, and green algae
• Red algae are the first unicellular organism
• Green algae share chlorophyll types, cellulose cell walls, and store food as starch

Algae Similarities

• Contain chlorophylls a and b
• Have cellulose-based cell walls
• Possess similar genetic information
• Store food as starch

Adaptations for Land Survival

• Protection from drying out
• A transport system for water
• A System to support the plant

Vascular Plants

• Early land plants lacked vascular tissue for long-distance transport
• Vascular tissue evolved in vascular plants

Non-Vascular Plants

• Non-vascular plants (mosses, liverworts, hornworts) lack true roots, stems, and leaves
• Are small in size

Vascular Plants

• Vascular plants contain seedless like ferns, seed producing: angiosperms like monocot and dicot and gymnosperms

Fungi Kingdom

Eukaryotic Heterotrophic Multicellular (mostly) Composed of hyphae (filaments) forming mycelium Reproduce sexually and asexually

Fungi Classification by Nutrition

• Parasitic fungi absorb nutrients from living hosts
• Predatory fungi trap prey
• Mutualistic fungi have partnerships with other organisms
• Saprobial fungi feed on dead organisms

Fungi Types

• Zygospore fungi (e.g., mold)
• Sac fungi (e.g., yeast) produce spores
• Club fungi (e.g., mushrooms)

Animal Kingdom

• Characteristics for classification of animals

Vertebrate and Invertebrate

• animals without a backbone
• animals with a backbone (largest animal being arthropods)

Animal Organization

• Levels of organization differ in structure, tissues, and organ systems
• Body layers: Ectoderm, mesoderm, endoderm

Animal Symmetry

• Bilateral symmetry (equal halves)
• Radial symmetry (circular arrangement)

Animal Body Cavity

• Acoelomates (no body cavity)
• Coelomates (fluid-filled body cavity)

Segmentation

• Division of the body into sections.

Animal Movement

• Movement can be complex, fast, stagnant/stationary movement
• Sessile is unmoving

Animal Reproduction

• Most animals reproduce sexually (gametic reproduction)
• Zygotes produced by external or internal fertilization
• Some animals also reproduce asexually

Animal Characteristics

• Multicellular
• Eukaryotic
• Lack cell walls
• Heterotrophic

Phylogenetic Trees

• Phylogenetic trees can be constructed based on given data to show relationships

Explore the classification of life, covering the morphological, biological, and phylogenetic species concepts. Learn about taxonomy, binomial nomenclature, and the three domains of life: Bacteria, Archaea, and Eukarya. Also, study species relationships using anatomical, physiological, and DNA evidence.