Download Animal Kingdom: Evolution and Diversity

Bio 10
Lecture Notes 8: Animal Diversity and Physiology
SRJC
1.) Animal Kingdom: Evolution and Diversity
 Characteristics of Animals
 Multicelled
 Aerobic heterotrophs
 Sexual reproduction
 Some also reproduce asexually
 Embryos produce primary tissues
 Motile at some stage
 Animal Lineages
 Vertebrates (single phylum: Chordata)
 Mammals
 Birds
 Reptiles
 Amphibians
 Fishes
 Invertebrates (many phyla)
 No backbone
 Animal Origins
 Monophyletic group
 Ediacarans
 Oldest date to 610 million years ago
 Animals probably arose from Ediacaran ancestors about 610 million years
ago.
 Variety of forms
 Early animals were thin, flat-bodied, with a good surface-to-volume ratio
for absorbing nutrients.
 Cambrian explosion of diversity
 During the Cambrian, animals underwent an enormous adaptive radiation
resulting in all of the major groups of animals
 Animal Diversity
 Many characteristics are used to group animals and determine evolutionary links
 Body Plans
 Symmetry
 Segmentation and cephalization
 Body cavities
 Digestive systems (none, incomplete or complete)
 Embryonic Development (protostomes and deuterostomes)
 Body Plans
 Radial symmetry
 Parts arrayed around a central point
 Bilateral symmetry
 Two halves that mirror each other
 Cephalization
 Concentration of nerve and sensory cells at anterior end
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Lecture Notes 8: Animal Diversity and Physiology
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 Segmentation
 Repeating series of body units
 Units may or may not be similar to one another
 Earthworms: segments appear similar
 Insects: segments may be fused and/or have specialized functions
 Body Cavities
 Coelom- (lined with peritoneum) is a space between the gut and body wall that
allows internal organs to expand and operate freely
 Acoelomate
 Some animals (flatworms) do not have a coelom but instead are packed
solidly with tissue between the gut and body wall
 Pseudocoelomate
 Others, such as roundworms, have a “false” coelom (pseudocoel), not
lined with peritoneum
 Coelomate
 Most animals are coelomates and have a “true” coelom, lined with
peritoneum
 Digestive Systems Region where food is digested and then absorbed
 No digestive system- intracellular (in cell) digestion (e.g. sponges)
 Incomplete digestive system ( saclike gut)
 One opening for taking in food and expelling waste (e.g. flatworms, sea
anemones)
 Complete digestive system
 Opening at both ends, mouth and anus
 Sponges
 No symmetry, tissues, or organs
 Filter feeders with intra-cellular digestion, no digestive system
 Reproduce sexually
 Microscopic swimming larva
 Cnidarians
 Radial symmetry
 Only animals that produce nematocysts
 Epithelial tissues
 Nerve net
 Hydrostatic skeleton
 Saclike gut (incomplete digestive system)
 Medusa and polyp forms
 Jellyfish, corals, sea anemones, hydras
 Protostome vs Deuterostome
 Two animal lineages distinguished by embryonic development
 Protostome (first mouth)- blastopore develops into mouth
 (e.g.) insects, snails, worms
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Lecture Notes 8: Animal Diversity and Physiology
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 Deuterostome (second mouth) blastopore develops into anus
 (e.g.) seastars, vertebrates
 Flatworms
 Bilateral, cephalized, no body cavity
 Most are hermaphrodites
 Include
 Turbellarians (including planarians)
 Flukes (including schistosomes)
 Tapeworms
 Schistosomes
 Parasitic flatworms
 Complicated life cycles, infect multiple hosts at different stages
 Larval stage infects a mollusk
 Adult infects a vertebrate
 Annelids
 Segmented, coelomates
 Earthworms
 Leeches
 Marine polychaetes
 Some with rudimentary brains and nerve cords
 Setae
 Chitin-reinforced bristles for crawling
 Oligochaetes
 Few bristles per segment (earthworms)
 Polychaetes
 Many bristles per segment (marine worms)
 Leeches
 Mollusks
 Bilateral, soft-bodied, coelomate
 Many have a shell or reduced version of one
 Mantle drapes over body and secretes shell
 Molluscan Diversity
 Gastropods (snails)
 Chitons
 Bivalves (clams, etc)
 Cephalopods (squids, octopuses)
 Cephalopod Adaptations
 Closed circulatory system
 Increases oxygen
 Squids
 Fastest invertebrates
 Jet propulsion
 Octopuses
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 Smartest invertebrates
 Largest brains
 Most complex eye among inverts.
 Roundworms (Nematodes)
 Bilateral, cephalized
 Pseudocoelom
 Complete digestive system
 Most free-living
 Some parasitize plants, animals, or humans
 Trichinosis
 Elephantiasis
 Arthropods
 Invertebrate group with the greatest number of species
 Five lineages:
 Trilobites (extinct)
 Chelicerates (spiders, mites, ticks, scorpions)
 Crustaceans (crabs, shrimps, barnacles)
 Insects
 Myriopods (centipedes, millipedes)
 Adaptations for Success
 Hardened exoskeleton
 Jointed appendages
 Fused and modified segments
 Respiratory structures
 Specialized sensory structures
 Specialized developmental stages
 Exoskeleton
 Molting of the cuticle
 Metamorphosis
 Division of labor between different developmental stages
 Growth as embryo (caterpillar)
 Reproduction and dispersal as adult (butterfly)
 Chelicerates
 Marine chelicerates : horseshoe crabs, sea spiders
 Arachnids (terrestrial chelicerates); Spiders, Mites, Scorpions, Chiggers,
“Daddy longlegs”, Ticks
 Crustaceans
 Most are marine, some freshwater, a few terrestrial
 Head has two pairs of antenna, three pairs of food-handling appendages
 Insects
 3 Segments (head, thorax, abdomen)
 The only winged invertebrates
 More than 800,000 known species
 High reproductive capacity
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Lecture Notes 8: Animal Diversity and Physiology
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SRJC
The most successful animals in terms of
 Distribution
 Number of species
 Population size
 Competitive adaptations
 Exploitation of diverse foods
 Echinoderms
 Marine group
 Calcium carbonate spines or plates
 No brain
 Tube feet
 Adults radial with bilateral features, but considered bilateral
 Chordates
 Chordate Features
 Notochord supports body
 Nervous system develops from dorsal nerve cord
 Embryos have pharynx with slits
 Embryos have tail that extends past anus
 Tunicates
 Notochord, tail and nerve cord occur only in larval stage (tadpole larval)
 Neoteny (paedomorphosis): sexual maturity in larval stage
 Possible mechanism for rise of vertebrates from tunicate ancestor
 Lancelet: An invertebrate Chordate
 Craniates (vertebrates)
 A chamber of cartilage or bone holds the brain
 Fishes
 Amphibians
 Reptiles
 Birds
 Mammals
 Key Innovations
 Shift from notochord to vertebrae
 Nerve cord expanded into brain
 Evolution of jaws
 Paired fins evolved, gave rise to limbs
 Gills and eventually lungs
 Jawed Fishes
 Most diverse and numerous group of vertebrates
 Cartilaginous fishes
 Sharks and rays
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Lecture Notes 8: Animal Diversity and Physiology
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 Bony fishes
 Ray-finned fishes:
 Soft ray fishes
 Salmonids (salmon, trout)
 Cyprinids (carp, gold fish, Koy)
 Spiny ray fishes
 Perciform (perch, bass, blue gill)
 Scorpiniform (sculpin, rock fish, ling cod)
 Scrombiform (tuna, sword fish, etc)
 Lobe-finned fishes
 Lungfishes and coelocanths
 Very ancient, mostly extinct, group
 Likely gave rise to terrestrial vertebrates
 Early Amphibians
 Fishlike skull and tail
 Four limbs (tetrapods)
 Short neck
 Modern Amphibians
 Require water at some stage in life cycle; most lay eggs in water
 Lungs are less efficient than those of other vertebrates
 Skin serves as respiratory organ
 Frogs, toads, salamanders
Rise of Amniotes
 Arose during Carboniferous
 Adaptations to life on land
 Tough, scaly skin
 Internal fertilization
 Amniote eggs
 Water-conserving kidneys
Living Reptiles
Not a monophyletic group, several ancestral groups
 Crocodilians
 Turtles
 Snakes and lizards
Dinosaurs
 Descended from Triassic reptiles
 Several mass extinctions, ending with K-T asteroid impact
 Some are now considered early birds
Birds
 Vertebrates with feathers
 Diverse
 Good learners
 Diverged from small dinosaurs during Mesozoic
 Amniote eggs fertilized internally
Feathers and Flight
 Flight required full-body modification
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 Bone structure, respiration, circulation
 Wings, feathers, musculature
 Mammals
 Mammal Characteristics
 Hair
 Mammary glands
 Distinctive teeth
 Highly developed brain
 Extended care for young
 Three Mammalian Lineages
 Monotremes
 Egg-laying mammals
 Marsupials
 Pouched mammals
 Eutherians
 Placental mammals
2.) Animal Physiology
 Required Nutrients
 Water
 Carbohydrates
 Lipids
 Proteins
 Minerals
 Vitamins
 Water
 Makes up ~90% of some animals
 Makes up a major portion of many body parts
 Humans require at least 1 L / day
 Carbohydrates
 Main source of energy
 High in bulk fiber
 Refined carbohydrates do not supply need
 Obesity
 Americans consumption ~2 lb refined sugar/week
 Lipids
 Parts of membranes
 Energy reserves
 Essential fatty acids
 (olive oil, canola oil)
 Saturated fats
 Roughly 40% of American diet
 Proteins
 Consist of amino acids hooked together
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Lecture Notes 8: Animal Diversity and Physiology
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20 amino acids
8 essential amino acids
Animal protein contains all 20 amino acids
Vegetables do not contain required balance of amino acids for humans
 A vegetable does not provide complete protein
 Complementarities can supply all essential amino acids.
 Beans supply lysine, corn supplies methionine
 Minerals
 17 essential minerals
 Inorganic substances: Iron, iodine, zinc, calcium, sulfur, potassium, chloride,
magnesium, etc.
 Required for growth, metabolism, survival
 Deficiencies – stunted growth or weak
 Vitamins
 13 essential vitamins
 Complex organic compounds
 Play metabolic role cofactors and coenzymes
 Animals cannot synthesize themselves
 Water Soluble vitamins
 Taken in excess – eliminated in urine generally do no harm
 C, B complex (B1, B2, B6, B12, niacin)
 Fat Soluble vitamins
 Taken in excess – stored in fatty tissues can cause serious health problems
 A, D, E, K
 Simple Digestive Processes
 Intracellular Digestion
 Phagocytosis
 Extracellular Digestion
 carbohydrates  simple sugar
 proteins  amino acids
 lipids  glycerol & fatty acids
 Digestive Systems
 Incomplete Digestive System
 Mouth and gut, no anus
 Complete Digestive System
 Mouth, Pharynx, Esophagus, Crop/gizzard (birds and grass hoppers),
Stomach, Intestine, Anus
 Digestive System Functions
 Mechanical Processing – breakdown, mixing, and food movement
 Secretion – release of digestive enzymes that aid digestion
 Digestion – breakdown of food particles
 Absorption – passage of digested nutrients and fluid from the tube (extracellular
space) into the body’s cells
 Elimination – expulsion of undigested materials
 Vertebrate Mouth Specializations
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 Herbivores- have teeth for grinding (molars are well developed)
 Carnivores- have teeth for tearing and chewing flesh (canines well developed)
 Omnivores have combination of above
 Circulatory Systems
 Single-celled organisms, direct exchange with environment
 Circulatory Systems
 Rapidly transports substances to and from cells
 May carry gases, food, chemical messages, waste material and living cells
 Interstitial fluid bathes tissues
 Heart – muscular blood vessel that acts as a pump
 Open Circulatory Systems
 Vessels empty into interstitial fluid, blood is re-collected
 Closed Circulatory System
 Vessels are continuous, but increasingly small
 Hearts
 Fish – 2 chambered heart
 Amphibians – 3-chambered heart
 Birds and Mammals – 4-chambered heart 2 ventricles 2 atria
 Atrium – thin-walled; receives blood from body; pumps to ventricle
 Ventricle – muscular wall; forces blood into major arteries
 Cellular Respiration
 C6H12O6 + O2  CO2 + H2O + energy
 Respiration in Water and Air
 aquatic environments- involves gills
 terrestrial environments- involves lungs
 Gas Exchange –
 Surface exchange- directly across epidermis, found in small animals with good
SA/V ratio
 Vascular exchange- across gills or lungs, in larger animals, provide good SA/V
ratios
 Gills- external structures
 Lungs- internal structures
 Trachea- only found in insects, like lungs
 Gills
 Gill Filament- has small branches for increased surface area
 Countercurrent Exchange- provides efficient gas exchange with water
 Lungs
 Amphibians have inefficient gas exchange system, augmented by exchange
through skin
 Birds- need extra efficient system for flight, have air sacs that re-run air through
lungs
 Human- air is driven into lungs by downward movement of diaphragm which
expands lungs. Diaphragm contraction, expels air at exhalation
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3.) Animal Organ Systems
3.1) Human Digestion
 Human Digestive System
 Complete system with many specialized accessory glands and organs
 About 10 meters long (30 ft)
 Lined with mucus-secreting epithelium
 Movement is one way, from mouth to anus
 Major Components
 Mouth (oral cavity)
 Pharynx (throat)
 Esophagus
 Gut
 Stomach
 Small intestine
 Large intestine
 Rectum
 Anus
 Accessory Organs
 Salivary glands
 Secrete saliva
 Liver
 Secretes bile
 Gallbladder
 Stores and concentrates bile
 Pancreas
 Secretes digestive enzymes
 Mechanical Processing
 Food is reduced down to its molecular components throughout the digestive
process
 First it must be broken mechanically in the mouth
 Teeth break down food
 Saliva
 Produced by salivary glands at back of mouth and under tongue
 Saliva includes
 Salivary amylase (enzyme)
 Bicarbonate (buffer)
 Mucins (bind food into bolus)
 Water
 Swallowing
 Complex reflex
 Tongue forces food into pharynx
 Epiglottis and vocal cords close off trachea; breathing temporarily ceases
 Food moves into esophagus, then through esophageal sphincter into stomach
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 Structure of Stomach
 J-shaped organ lies below the diaphragm
 Sphincters at both ends
 Outer serosa covers smooth muscle layers
 Inner layer of glandular epithelium faces lumen
 Stomach Secretions
 Secreted into lumen (gastric fluid)
 Hydrochloric acid (HCl)
 Mucus (protective)
 Protein-digesting enzymes
 Stomach cells also secrete the hormone gastrin into the bloodstream
 Small Intestine
 Longest segment of digestive tract
 Receives chyme from stomach
 Receives secretions from liver, gallbladder, and pancreas
 Pancreas – secretes enzymes to breakdown food, sodium bicarbonate to
neutralize stomach acid
 Liver – secretes bile salts to breakdown fats
 Digests food into absorbable subunits
 Pancreas – secretes enzymes to breakdown food, sodium bicarbonate to neutralize
stomach acid
 Liver – secretes bile salts to breakdown fats
 Walls of Small Intestine
 Projections into the intestinal lumen increase the surface area available for
absorption
 Nutrient Absorption
 Passage of molecules into internal environment
 Occurs mainly in small intestine
 Various methods of absorption
 Osmosis, transport proteins, diffusion
 Absorption Mechanisms
 Monosaccharides & amino acids are actively transported across plasma
membrane of epithelial cells, then from cell into internal environment
 Fat Absorption
 Bile salts emulsify lipids
 Into the Blood
 Glucose and amino acids enter blood vessels directly
 Triglycerides enter lymph vessels, which eventually drain into blood vessels
 Large Intestine (Colon)
 Concentrates and stores feces
 Actively transports sodium ions out of lumen; water follows (by osmosis)
 Resident bacteria produce vitamins
 Rectum
 Final portion of large intestine
 Stores feces
 Anus
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 Final sphincter
 Controls Over Digestion
 Nervous system
 Secretion of acids and enzymes
 Smooth muscle contractions
 Endocrine system
 Appetite (leptin and grehlin)
 Digestion (gastrin, secretin, CCK)
3.2) Circulation and Respiration
 Blood Flow and Gas Exchange
 Rate of blood flow varies with diameter of blood vessels
 Slowest flow in smallest vessels, the capillaries
 Gases are exchanged between blood and interstitial fluid across capillary walls
 Vertebrate Circulatory Systems
 4 chambered hearts in birds and mammals
 Heart is fully partitioned into two halves. Blood circulates in two circuits: from
the heart’s right half to lungs and back, then from the heart’s left half to oxygenrequiring tissues and back
 Double Circuits
 In birds and mammals
 Right half of heart
 Pulmonary circuit
 Heart to lungs and return
 Left half of heart
 Systemic circuit
 Heart to body tissues and return
 Functions of Blood
 Transports oxygen and nutrients to cells
 Carries carbon dioxide and wastes away from cells
 Helps stabilize internal pH
 Carries infection-fighting cells
 Helps equalize temperature
 Components of Blood
 Plasma
 Water
 Proteins
 Dissolved materials
 Cells
 Red blood cells
 White blood cells
 Platelets
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 Blood Cell Development
 Stem cells in bone marrow produce blood cells and platelets
 Body continually replaces blood cells
 Erythrocytes (Red Cells)
 Most numerous cells in blood
 Transport oxygen and carbon dioxide
 Colored red by oxygen-binding pigment (hemoglobin)
 Have no nucleus when mature
 Leukocytes (White Cells)
 Function in housekeeping and defense
 Cell types
 Basophils
Dendritic cells
 Eosinophils
B cells
 Neutrophils
T cells
 Macrophages
 Platelets
 Membrane-bound cell fragments
 Derived from megakaryocytes, which arise from stem cells
 Release substances that initiate blood clotting
 Clotting Mechanism
 Prothrombin is converted to thrombin
 Fibrinogen is converted to fibrin
 Fibrin forms net that entangles cells and platelets
 Human Heart Is a Double Pump
 Partition separates heart into left and right sides
 Each pumps blood through a different circuit
 Pulmonary Circuit
 Heart to lungs
 Oxygenates blood
 Systemic Circuit
 Starts at aorta
 Carries oxygenated blood to body tissues
 Four Chambers
 Each side has two chambers
 Upper atrium
 Lower ventricle
 Valves between atria and ventricles
 Cardiac Cycle
 Diastole-(early) both chambers relax, atria fill
 Diastole (mid-late) atria contract, ventricles fill
 Systole ventricles contract
 Conduction and Contraction
 SA node in right atrium is pacemaker
 Electrical signals cause contraction of atria
 Signal flows to AV node and down septum to ventricles
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 Blood Vessels
 Arteries: carry blood away from heart
 Arterioles: diameter is adjusted to regulate blood flow
 Capillaries: diffusion occurs across thin walls
 Blood Pressure
 Highest in arteries, lowest in veins
 Usually measured in the brachial artery
 Systolic pressure is peak pressure
 Ventricular contraction
 Diastolic pressure is the lowest pressure
 Ventricular relaxation
 Resistance
 Adjusted at arterioles
 Vasodilation
 Increases vessel diameter
 Lowers blood pressure
 Vasoconstriction
 Decreases vessel diameter
 Increases blood pressure
 Capillary Beds
 Diffusion zone; site of exchange between blood and interstitial fluid
 Capillary wall is one cell thick
 Flow is slow; allows gases to diffuse across membranes of blood cells and across
endothelium
 Capillary Exchange
 Delivers to the interstitial fluid
 Sugar
 Amino acids
 Fatty acids
 Glycerol
 White blood cells
 Gases
 Bulk Flow in Capillary Bed
 Normally, ultrafiltration only slightly exceeds reabsorption
 Fluid enters interstitial fluid and returned to blood via the lymphatic system
 High blood pressure causes excessive ultrafiltration and results in edema
 The Venous System
 Blood flows from capillaries to venules to veins
 Veins are large-diameter vessels with some smooth muscle in wall
 Vein Function
 Valves in veins prevent blood from flowing backward
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3.3) Respiration
Respiration
 Physiological process by which oxygen moves into an animal’s internal
environment and carbon dioxide moves out
 Aerobic respiration
 Cellular process, produces ATP
 Oxygen is used
 Carbon dioxide is produced
Respiratory System
 Works with the circulatory system to deliver oxygen and remove carbon dioxide
 Also helps regulate acid-base balance
Pressure Gradients
 Concentration gradients for gases
 Gases diffuse down their pressure gradients
 Gases enter and leave the body by diffusing down pressure gradients across
respiratory membranes
Factors In Gas Exchange
 Surface-to-volume ratio
 Small, flat animals
 Ventilation
 Adaptations enhance exchange rate
 Respiratory pigments
 Hemoglobin and myoglobin
Surface-to-Volume Ratio
 As animal size increases, surface-to-volume ratio decreases
 Small, flat animals can use the body surface as their respiratory surface
 Larger animals have special structures to increase respiratory surface, such as gills
or lungs
Vertebrate Lungs
 Originated in some fishes as outpouching from gut wall (swim bladder)
 Allow gas exchange in air and in oxygen-poor aquatic habitats
3.4) Human Respiratory System
 Breathing
 Moves air into and out of lungs
 Occurs in a cyclic pattern called the respiratory cycle
 One respiratory cycle consists of inhalation and exhalation
 Inhalation
 Diaphragm flattens
 External intercostal muscles contract
 Volume of thoracic cavity increases
 Lungs expand
 Air flows down pressure gradient into lungs
 Normal (Passive) Exhalation
 Muscles of inhalation relax
 Thoracic cavity recoils
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 Lung volume decreases
 Air flows down pressure gradient and out of lungs
Active Exhalation
 Abdominal and internal intercostal muscles contract
 Contraction decreases thoracic cavity volume more than passive exhalation
 Greater volume of air flows out to equalize intrapulmonary pressure with
atmospheric pressure
Respiratory Membrane
 Area between an alveolus and a pulmonary capillary
 Oxygen and carbon dioxide diffuse across easily
Oxygen Transport
 Most oxygen is bound to heme groups in hemoglobin in red blood cells
 Hemoglobin has higher affinity for oxygen when it is at high partial pressure (in
pulmonary capillaries)
 Lower affinity for oxygen in tissues, where partial pressure is low
Bicarbonate Formation
 Most carbon dioxide is transported as bicarbonate
 Some binds to hemoglobin
 Small amount dissolves in plasma
Control of Breathing
 Nervous system controls rhythm and magnitude of breathing
 Breathing is adjusted as a result of changes in
 Carbon dioxide levels
 Oxygen levels
 Blood acidity
A Carranza
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7/25/2015