Unit 5 Study Guide: Microbial Diversity, Evolution of Vertebrates, and Animal Structure & Function

Microbial Life: Prokaryotes and Protists

Major Shapes and Types of Prokaryotes

Prokaryotes are classified based on their shapes and cell wall composition. These characteristics are fundamental for identification and understanding their ecological roles.

• Bacilli: Rod-shaped bacteria. Example: Escherichia coli.

• Cocci: Spherical bacteria. Example: Staphylococcus aureus.

• Spirochetes: Spiral-shaped bacteria. Example: Treponema pallidum.

• Gram-positive: Bacteria with thick peptidoglycan cell walls that retain crystal violet stain.

• Gram-negative: Bacteria with thin peptidoglycan layers and an outer membrane; do not retain crystal violet stain.

• Peptidoglycan: A polymer forming the cell wall of most bacteria, providing structural support.

Metabolic Diversity in Prokaryotes

• Chemoautotrophs: Obtain energy from inorganic chemicals and carbon from CO2.

• Chemoheterotrophs: Obtain both energy and carbon from organic molecules.

• Photoautotrophs: Use light energy to convert CO2 into organic compounds. Example: Cyanobacteria.

• Photoheterotrophs: Use light for energy but require organic compounds for carbon.

Archaea: Extremophiles

• Methanogens: Archaea that produce methane as a metabolic byproduct; often found in anaerobic environments.

• Thermophiles: Archaea that thrive in extremely hot environments, such as hot springs.

Protists: Diversity and Structure

• Diatoms: Unicellular algae with silica cell walls; important primary producers in aquatic ecosystems.

• Dinoflagellates: Mostly marine protists with two flagella; some cause red tides.

• Brown algae: Large, multicellular algae (e.g., kelp); important in marine habitats.

• Pseudopodia: Temporary extensions of the cell membrane used for movement and feeding (e.g., in amoebas).

• Foraminiferans: Protists with porous shells (tests) made of calcium carbonate; use pseudopodia for movement.

• Radiolarians: Protists with intricate silica skeletons and radiating pseudopodia.

• Flagella: Long, whip-like structures used for movement in many protists and some bacteria.

The Evolution of Vertebrate Diversity

Major Vertebrate Groups and Characteristics

• Monotremes: Egg-laying mammals (e.g., platypus).

• Marsupials: Mammals with pouches for developing young (e.g., kangaroo).

• Mammals: Vertebrates with hair and mammary glands; include monotremes, marsupials, and placental mammals.

• Tetrapods: Vertebrates with four limbs (amphibians, reptiles, birds, mammals).

• Amniotes: Vertebrates with amniotic eggs, allowing reproduction on land (reptiles, birds, mammals).

• Ectothermic: Organisms that rely on external sources for body heat (e.g., reptiles, amphibians).

• Endothermic: Organisms that regulate body temperature internally (e.g., birds, mammals).

Scientific View of Birds

• Birds are considered a group of reptiles, specifically derived from theropod dinosaurs.

• Key adaptations include feathers, hollow bones, and endothermy.

Evolutionary Trees

• Evolutionary trees (phylogenies) depict relationships among groups based on shared characteristics and ancestry.

• Reading a tree involves tracing branches from common ancestors to modern groups.

Major Defining Characteristics in Mammalian Evolution

• Key traits include hair, mammary glands, differentiated teeth, and three middle ear bones.

• Placental development distinguishes eutherians from monotremes and marsupials.

Unifying Concepts of Animal Structure and Function

Levels of Organization in Life

• Molecule → Cell → Tissue → Organ → Organ System → Organism

• Each level builds on the previous, increasing complexity and specialization.

Tissues: Types, Structure, and Function

• Tissue: A group of similar cells performing a specific function.

• Organ: Structure composed of multiple tissue types working together (e.g., heart).

• Organ System: Group of organs working together (e.g., respiratory system).

Major Categories of Tissues

• Epithelial Tissue: Covers body surfaces and lines cavities; functions in protection, absorption, and secretion.

• Connective Tissue: Supports and binds other tissues; includes bone, blood, cartilage, adipose, and loose connective tissue.

• Muscle Tissue: Responsible for movement; includes skeletal, cardiac, and smooth muscle.

• Nervous Tissue: Conducts electrical impulses; includes neurons and supporting cells.

Examples and Locations of Tissues

• Epithelial: Skin, lining of digestive tract, respiratory passages.

• Connective: Tendons, ligaments, fat, blood, bone.

• Muscle: Skeletal muscles (attached to bones), heart (cardiac), walls of hollow organs (smooth).

• Nervous: Brain, spinal cord, nerves.

How to Name Epithelial Tissue

• Based on number of layers (simple = one layer; stratified = multiple layers) and cell shape (squamous = flat, cuboidal = cube-shaped, columnar = tall).

• Example: Simple squamous epithelium (single layer of flat cells).

Types of Connective Tissues and Their Characteristics

Type	Defining Characteristics	Location/Function
Loose Connective	Most common; loosely arranged fibers	Binds epithelia to underlying tissues
Adipose	Stores fat	Insulation, energy storage
Fibrous	Dense collagen fibers	Tendons, ligaments
Cartilage	Flexible matrix	Joints, ear, nose
Bone	Rigid matrix with calcium	Skeletal support
Blood	Cells in plasma	Transport of substances

• Most common connective tissue: Loose connective tissue.

Types of Muscle Tissues and Their Functions

Type	Function	Location
Skeletal	Voluntary movement	Attached to bones
Cardiac	Pumps blood	Heart
Smooth	Involuntary movement	Walls of hollow organs

Nervous Tissue

• Neurons: Cells that transmit electrical signals.

• Nerve: Bundle of neuron fibers.

Organs of the Respiratory System

• Nose, pharynx, larynx, trachea, bronchi, lungs, alveoli.

Homeostasis and Feedback Mechanisms

• Homeostasis: Maintenance of a stable internal environment.

• Negative Feedback: Mechanism that counteracts a change to maintain balance (e.g., body temperature regulation).

• Positive Feedback: Mechanism that amplifies a change (e.g., blood clotting, childbirth contractions).

Physiologist

• A scientist who studies the functions and mechanisms of living organisms.

Structure-Function Relationship

• Biological structures are adapted to their functions (e.g., thin alveoli walls for gas exchange).

Examples of Positive and Negative Feedback

Feedback Type	Example
Negative	Regulation of blood glucose by insulin
Positive	Oxytocin release during childbirth

Additional info: Academic context and examples have been added to expand on the brief points in the original study guide.