Animal Diversity and Function

Animals: Core Characteristics

Eukaryotes, multicellular heterotrophs, lack cell walls, and use ingestion.

Mammalian Teeth: Carnivore

Serrated teeth like a knife for cutting and tearing meat.

Mammalian Teeth: Herbivore

Blunt teeth with many molars for grinding plants and breaking cell walls.

Four Steps of Food Processing

Ingestion, digestion, absorption, and elimination.

Cnidarian Digestive System

A gastrovascular cavity with a single opening for digestion, circulation, and support.

Alimentary Canal

A digestive tube with two specialized openings.

Gizzard Function

Stores food and performs mechanical breakdown using rocks and sand in toothless animals.

Liver Function in Digestion

Processes and detoxifies blood coming from the intestines.

Herbivore Digestive Tract Adaptation

Long digestive tract with a cecum housing microbes to break down plants.

Ruminants

Grazing mammals with a 4-chambered stomach and different microbes in each section.

Respiratory Surface Requirements

Must be thin and moist for the diffusion of O2 and CO2.

Advantages of Breathing Air over Water

Air has a higher O2 concentration and is much lighter and easier to move.

Tracheal System

Tiny branching tubes transporting O2 directly to body cells without using blood.

Single Circulation

Blood is pumped once through a 2-chambered heart.

Double Circulation

Blood is pumped twice, maintaining higher blood pressure via 3- and 4-chambered hearts.

Endothermic Animals

Use heat generated by metabolism to maintain a warm, steady body temperature.

Ectothermic Animals

Absorb external heat rather than generating much of their own.

Four Mechanisms of Heat Exchange

Conduction, convection, radiation, and evaporation.

Countercurrent Heat Exchange

Warm and cold blood flow in opposite directions to conserve heat in birds and penguins.

Five Categories of Sensory Receptors

Thermoreceptors, mechanoreceptors, pain receptors, chemoreceptors, and electromagnetic receptors.

Snake Pit Organ

A thermoreceptor adaptation used for detecting heat to catch prey.

Shark Electroreceptors

Electromagnetic receptors in pores used to detect electric fields from muscle movement.

Hydrostatic Skeleton

Fluid held under pressure providing support, found in worms and cnidarians.

Endoskeleton

An internal skeleton made of living, growing bones and joint cartilage.

Muscle and Bone Interaction

Muscles connect to bones via tendons, can only pull, and work in paired antagonistic sets.

Excretory System: Nephron

The functional unit of the kidney that filters blood, reabsorbs nutrients, and produces urine.

Neuron Structure and Function

A nerve cell featuring dendrites that receive signals and an axon that transmits electrical impulses.

Osmoregulation

The process by which animals regulate solute concentrations and balance water gain and loss.