Bio 1202: Exam 3

A flexible rod providing structural support; in vertebrates, it becomes part of the spinal column.

Notochord

Develops into the central nervous system (brain and spinal cord).

Dorsal hollow nerve cord

Function as filter-feeding structures in primitive chordates and develop into gills or parts of the head and neck in higher groups.

Pharyngeal slits or clefts

Extends beyond the anus and aids in movement and balance; it is often reduced in later development.

Post-anal tail

Tunicates have free-swimming larvae that display all four chordate traits, but adults lose most of them and become sessile filter feeders.

Urochordata (Tunicates)

Lancelets keep all four chordate features into adulthood; they are small, fish-like marine animals that use their pharyngeal slits for filter feeding.

Cephalochordata (Lancelets)

Evolved from early chordates during the Cambrian period, gaining new traits that allowed greater movement and sensory control.

Vertebrates

Protects the dorsal nerve cord and replaces the notochord's supportive role.

Backbone (vertebrae)

Encloses the brain, providing protection and a base for sensory organs.

Skull

Embryonic cells that migrate and form bones, cartilage, and nerves in the head and face.

Neural crest cells

Increase genetic complexity, allowing for advanced development of the nervous system and skeleton.

Duplicated Hox genes

Include hagfishes and lampreys; both lack jaws and true vertebrae but are still considered vertebrates due to rudimentary cartilage vertebrae.

Cyclostomes (Jawless Vertebrates)

Marine scavengers that produce large amounts of slime for defense.

Hagfishes

Often parasitic, using their round, toothed mouths to attach to other fish and feed on blood.

Lampreys

Evolved jaws from modified skeletal rods that once supported pharyngeal slits, allowing them to grasp and chew food.

Gnathostomes (Jawed Vertebrates)

Derived trait of gnathostomes that allows for active swimming.

Paired fins

Includes sharks, rays, and chimaeras; skeleton made mostly of cartilage instead of bone.

Chondrichthyes (Cartilaginous Fish)

Have a bony endoskeleton and lungs or lung derivatives like the swim bladder, which helps control buoyancy.

Osteichthyes (Bony Fish)

Cover osteichthyes and use an operculum to cover and move water over their gills.

Bony scales

One of the two main lineages of osteichthyes.

Ray-finned fish (Actinopterygii)

Have muscular fins with bones and joints, providing the foundation for the evolution of limbs in tetrapods.

Lobe-finned fish (Sarcopterygii)

Four-limbed vertebrates that evolved from lobe-finned ancestors and adapted to life on land.

Tetrapods

Limbs with digits, neck, and pelvic girdle fused to the backbone for weight support.

Derived traits of Tetrapods

A fossil species that shows the transition with fins that contain humerus, radius, and ulna—the same basic limb bones seen in all land vertebrates.

Tiktaalik

The earliest terrestrial tetrapods, including frogs, salamanders, and caecilians.

Amphibia

Most amphibians have a tadpole stage before becoming terrestrial adults.

Aquatic larval stage

Allows gas exchange but ties them to wet environments for reproduction due to eggs lacking shells.

Moist skin in Amphibians

Most species have external fertilization.

Fertilization in Amphibians

Shows the early adaptation from water to land while still depending on moisture.

Dual life in Amphibians

Include reptiles and mammals—the first vertebrates fully adapted to life on land.

Amniotes

Contains four protective membranes (amnion, chorion, yolk sac, allantois) allowing embryos to develop in dry environments.

Amniotic egg

A derived trait in amniotes for efficient lung breathing.

Rib-cage ventilation

Helps conserve water.

Less permeable skin in Amniotes

Includes turtles, snakes, lizards, crocodiles, and birds.

Reptilia

Protect reptiles against desiccation.

Keratin scales

Laid on land by reptiles.

SHELLED amniotic eggs

A reproductive strategy used by most reptiles.

Internal fertilization in Reptiles

Most reptiles rely on external heat sources to regulate body temperature.

Ectothermic

Birds maintain body temperature through metabolism.

Endothermic

Feathers, wings, and hollow bones for flight, making them highly energy-efficient.

Adaptations in Birds

Amniotes with hair and mammary glands.

Mammalia

Produce milk to nourish young.

Mammary glands

Provides insulation and sensory function.

Hair in Mammals

Supports high metabolic rates.

Endothermy in Mammals

Allow processing of various foods.

Differentiated teeth in Mammals

Monotremes (egg-laying), Marsupials (pouch), and Eutherians (placental).

Three main groups of Mammals

Trend from simple to complex structures, development of jaws and limbs, transition from aquatic to terrestrial life.

Evolutionary trends in Chordata

Deuterostomes that share ancestry with echinoderms but are distinguished by four chordate characteristics.

Chordates

Refers to the biological structure of an organism — the physical arrangement of its parts.

Anatomy

Refers to biological function — how those structures work.

Physiology

Helps it retain heat and survive in cold environments.

Emperor penguin's blubber

The relationship between form and function is the result of evolution by natural selection.

Evolution by natural selection

The rate of exchange depends on surface area.

Surface area

The amount of materials needed depends on volume.

Volume

As a cell becomes larger, its volume increases faster than its surface area, making diffusion inefficient.

Diffusion efficiency

Solved the problem of material exchange by allowing many small cells, each with a large surface area relative to volume.

Multicellularity

Larger, complex animals evolved specialized internal structures (like lungs, intestines, and kidneys) that are folded or branched to increase surface area for exchange.

Specialized internal structures

These internal exchange surfaces connect to the circulatory system, which transports materials to and from cells.

Circulatory system

Determines how efficiently materials like gases or nutrients can diffuse.

Surface area to volume ratio (SA/V)

Means faster exchange with the environment.

High SA/V ratio

Means slower exchange.

Low SA/V ratio

Increase surface area for diffusion.

Structures with folds

Has millions of microvilli, maximizing nutrient absorption.

Human small intestine

The basic functional units of life.

Cells

Groups of similar cells that perform a shared function.

Tissues

Made of multiple tissue types working together for a specific role.

Organs

Consist of multiple organs that coordinate to carry out major life functions like digestion or circulation.

Organ systems

Covers the outside of the body and lines internal organs and cavities.

Epithelial Tissue

Include protection, absorption, and secretion.

Epithelial functions

Include squamous (flat), cuboidal (cube-shaped), and columnar (tall); may be simple (one layer) or stratified (multiple layers).

Epithelial cell shapes

Holds tissues and organs together and provides support.

Connective Tissue

Liquid (blood), jellylike (cartilage), or solid (bone).

Matrix types

Fibroblasts (make fibers) and macrophages (engulf foreign material).

Main cell types in connective tissue

Collagenous (strength, flexibility), elastic (stretch, recoil), reticular (connect tissues).

Types of fibers in connective tissue

Responsible for movement of body or internal organs.

Muscle Tissue

Components of muscle tissue that contract.

Actin and Myosin Filaments

Voluntary, striated muscle attached to bones.

Skeletal Muscle

Involuntary muscle found in the digestive tract and blood vessels.

Smooth Muscle

Involuntary, striated muscle found only in the heart, with intercalated disks for coordination.

Cardiac Muscle

Specialized for communication and control.

Nervous Tissue

Cells that transmit electrical impulses.

Neurons

Cells that nourish and support neurons.

Glial Cells

Uses chemical messengers (hormones) released into the bloodstream.

Endocrine System

Uses electrical impulses along neurons.

Nervous System

Maintaining a stable internal environment despite external changes.

Homeostasis

Target value (e.g., normal body temperature) in feedback control systems.

Set Point

Detects changes (e.g., temperature receptors) in feedback control systems.

Sensor

Interprets input and triggers a response (e.g., hypothalamus) in feedback control systems.

Control Center

Returns the variable toward the set point (e.g., shivering or sweating) in feedback control systems.

Response

Reduces the initial stimulus and restores balance.

Negative Feedback

Amplifies the stimulus and pushes a process to completion.

Positive Feedback

Generate heat mainly through metabolism (e.g., mammals, birds).

Endothermic Animals

Gain heat mostly from the environment (e.g., reptiles, amphibians, fish).

Ectothermic Animals

Animals with a stable body temperature.

Homeotherms

Animals with a variable body temperature.

Poikilotherms

Four ways heat is exchanged with animals: radiation, evaporation, convection, conduction.

Heat Exchange

Hair, feathers, fur, or blubber that reduce heat loss.

Insulation

Adjusting blood flow to skin.

Circulatory adaptations

Increases heat loss by widening blood vessels.

Vasodilation

Conserves heat by narrowing vessels.

Vasoconstriction