Transcript Inquiry into Life Twelfth Edition

Lecture PowerPoint to accompany
Inquiry into Life
Twelfth Edition
Sylvia S. Mader
Chapter 30
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
30.1 Evolutionary Trends
Among Animals
• Characteristics of Animals
– Heterotrophic, acquire food by ingestion
– Locomotion by means of muscles
– Multicellular, high degree of cell specialization
– Adult is diploid
– Reproduction usually sexual, with embryo undergoing
developmental stages
Animal Diversity
30.1 Evolutionary Trends
Among Animals
• Invertebrates- lack an endoskeleton of bone or
cartilage
– All but one animal phylum are invertebrates
• Vertebrates- have an endoskeleton of bone or
cartilage
Evolutionary Tree
30.1 Evolutionary Trends
Among Animals
• Level of Organization
– Cellular: no true tissues; sponges
– Tissue: have ectoderm and endoderm;
cnidarians like hydra
– Organ: have ectoderm, endoderm, and
mesoderm; majority of animals
• Type of Body Plan
– Sac-Plan: incomplete digestive system (ex: cnidarians)
– Tube-Within-a-Tube Plan• inner tube is digestive system, outer tube is body wall; two
openings
30.1 Evolutionary Trends
Among Animals
• Type of Symmetry
– Asymmetrical:
– Radial Symmetry:
no particular symmetry
circular organization, can be bisected in any
plane to produce mirror images
– Bilateral Symmetry: definite right and left halves; only a cut down
the midline will produce mirror images
30.1 Evolutionary Trends
Among Animals
• Type of Body Cavity
– Acoelomate:
lacks a body cavity
– Pseudocoelomate: body cavity incompletely lined with
mesoderm
– Coelom:
cavity that contains organs, and is lined with
mesoderm
30.1 Evolutionary Trends
Among Animals
• Segmentation
– Repetition of body parts
– Molluscs and echinoderms are unsegmented
coelomates
– Annelids, arthropods, and chordates are segmented
coelomates
– Leads to specialization of body parts
• Jointed Appendages
– Specialized for locomotion
30.2 Introducing the Invertebrates
• Sponges: Multicellular
– Phylum Porifera
– Saclike body with many pores
• Lack organized tissues
– Filter feeders
• Amoeboid cells act as a circulatory device
– Asexual and Sexual Reproduction
• Hermaphroditic, usually not self-fertilizing
– Spicules
• For internal support
Simple Sponge Anatomy
30.2 Introducing the Invertebrates
• Cnidarians: True Tissues
– Phylum Cnidaria
– Multicellular, tubular or bell-shaped animals with
radial symmetry
– All aquatic, mostly marine
– Two germ layers during development, adults exhibit
true tissues
30.2 Introducing the Invertebrates
• Cnidarians: True Tissues
– Nematocysts-stinging cells unique to cnidarians
– Two body types: polyps and medusa
• Life cycle alternates between both forms in some; in others
one form is reduced or absent
– Gastrovascular cavity: sac-like body plan
– Includes corals, jellyfish, and hydrozoans
• Corals- polyps
• Jellyfish-medusae
• Hydrozoans-may have both forms
Cnidarian Diversity
30.2 Introducing the Invertebrates
• Cnidarians: True Tissues
– Hydra – a representative cnidarian (Class Hydrozoa)
• Freshwater, attaches to rocks and plants
• Small tubular polyp, sac-like body plan with a single opening
–
–
–
–
Outer tissue layer: epidermis from ectoderm
Inner layer: gastrodermis from endoderm
Longitudinal and circular muscle fibers present
Diffuse nerve net
• Digestion begins in gastrovascular cavity, completed in cells
• Can reproduce sexually and asexually (budding)
– Sexual reproduction
» hydra develops an ovary or testis in body wall-produces
gametes
Anatomy of Hydra
30.2 Introducing the Invertebrates
• Flatworms: Bilateral Symmetry
– Phylum Platyhelminthes
– Three germ layers, but not a true coelom
– Free-living flatworms have:
• Muscles, excretory, reproductive, and digestive systems
– Free-living flatworms lack:
• Respiratory and excretory systems
– Diffusion suffices
30.2 Introducing the Invertebrates
• Planarians
– Found in lakes, ponds, and streams
• Feed on small organisms such as worms and crustaceans
– Possesses an excretory system (flame cell system)
– Ladder-like nervous system
• Cephalization
– Reproduce both asexually and sexually
• Regeneration (asexual)
• Hermaphroditic (sexual)
Planarian Anatomy
30.2 Introducing the Invertebrates
• Parasitic Flatworms
– Tapeworms
• Endoparasites
• Range in length from several millimeters to 20 meters
• Tough outer tegument to protect from host’s enzymes
• Scolex-has hooks for attachment; not a sucker
• Body of segments called proglottids
– Organs of both sexes in each proglottid
– Fertilization is internal—proglottids filled with fertilized eggs are
called gravid
– Gravid proglottids drop off and pass out in feces
– Ingested by intermediate host—larvae become encysted
– Intermediate host is then eaten by definitive host and larvae
mature to adults
Life Cycle of a Tapeworm, Taenia
30.2 Introducing the Invertebrates
• Parasitic Flatworms
– Flukes
•
•
•
•
•
•
•
Endoparasites of many species
Body covered by a tough tegument
Two suckers: one for feeding, one for attachment
Alimentary canal is well-developed
Muscles and excretory system much like free-living flatworms
Poorly developed senses
Hermaphroditic, with a complex life cycle involving two
intermediate hosts– The liver fluke Clonorchis sinensis is an example
» eggs pass out of human in feces and enter a snaillarvae
leave the snail and burrow into muscles of a fish fish
ingested by human and adults form in the bile ducts
30.2 Introducing the Invertebrates
• Roundworms: Pseudocoelomates
– Phylum Nematoda
• Tube within a tube body plan
– Mouth and anus
• Body cavity (pseudocoelom)
• Hydrostatic skeleton
• Nonsegmented
• Some roundworms are free-living, others are parasitic
30.2 Introducing the Invertebrates
• Roundworms: Pseudocoelomates
– Ascaris
•
•
•
•
Move with whip-like motion
Most commonly parasites in pigs and humans
Females are much longer than males and highly prolific
Eggs enter host in uncooked vegetables, soil, or feces
– Larvae burrow out of intestine and migrate to heart and lungs
– Larvae are coughed up and swallowed
– Mature to adults in intestines
30.2 Introducing the Invertebrates
• Roundworms: Pseudocoelomates
– Other Roundworms
• Trichinosis
– Caused by Trichinella spiralis
– Humans contract the worm by eating undercooked pork
– Larvae migrate out of intestines and form painful cysts in the
muscles
• Elephantiasis
– Caused by a filarial worm
– Migrates into lymphatic vessels and prevents lymph drainage
– Swelling of limbs occurs
• Pinworms and hookworms
– Roundworm parasites which cause problems in children
» Pinworms
» Hookworms
30.3 Molluscs: Coelomates
30.3 Molluscs: Coelomates
• Coelomates (Characteristics)
– Bilateral symmetry
– Three germ layers
– Organ level of organization
– Tube-within-a-tube body plan
30.3 Molluscs: Coelomates
• Coelomates (Characteristics)
– Advantages:
• Free body movements
• Space for development of complex organs
• Greater surface area for absorption of nutrients
• Protection of internal organs
30.3 Molluscs: Coelomates
• Molluscs
– Second largest animal phylum
– Unique characteristics of molluscs
• Three distinct parts
– Visceral mass: includes most organs
– Foot: muscular portion used for locomotion
– Mantle: covering that envelopes visceral mass
» Mantle cavity-space between the two folds of the
mantle
» Mantle may secrete a shell
• Radula-rasping organ for feeding
Diversity of Molluscs
30.3 Molluscs: Coelomates
• Gastropods
– Nudibranchs, conchs, and snails
• Foot is flattened ventrally
• Move by muscle contractions along the foot
• Nudibranchs(sea slugs)
– lack shell
• Conchs and snails have a shell
– Protection, prevents dessication in land snails
• Aquatic gastropods have gills
• Terrestrial gastropods: mantle has lung-like function
30.3 Molluscs: Coelomates
• Cephalopods
– Squid, octopus, chambered nautilus
• Foot has evolved into tentacles
• Powerful beak and radula for feeding
• Extremely well-developed eyes; complex behaviors
• Ink glands- secrete “ink”as defense mechanism
Gastropod and Cephalopod Anatomy
30.3 Molluscs: Coelomates
• Bivalves
– Clams, oysters, scallops
• Two-part shells (valves)
• Gills enclosed in mantle cavity
• Filter-feeders: water enters through incurrent siphon
• Visceral mass
– Coelom is reduced
– Pericardial cavity is the only remains of the coelom
• Heart pumps blood to dorsal aorta and then to organs
– Described as an open system because blood not always in
vessels
30.3 Molluscs: Coelomates
• Bivalves– Clams, oysters, scallops
• Lack cephalization
– Nervous system consists of ganglia connected by nerves
• Digestive system
– Mouth with labial palps, esophagus, stomach, intestine
• Excretion is by kidneys
• Sexes are separate
Clam, Anodonta
30.4 Annelids: Segmented Worms
• Phylum Annelida
– Segmentation
– Hydroskeleton
– Tube-within-a-tube body plan-segmentation allows
specialization of systems
• Pharynx, esophagus, crop, gizzard, intestine, accessory
glands
• Closed circulatory system
• Nervous system consists of brain, ventral nerve cord, and
ganglia in each segment
• Excretory system consists of nephridia
– Excretion is through openings in the body wall
30.4 Annelids: Segmented Worms
• Polychetes
– Have setae• Bristles for anchoring worm or helping in locomotion
– Used for swimming and respiration
• Ragworms (ex: Nereis)
– Predators: eat crustaceans and other small animals
• Tube worms
– Tentacles that form a funnel-shaped fan
– Sessile filter feeders
• Polychaetes are seasonal breeders
Polychaete Diversity
30.4 Annelids: Segmented Worms
• Oligochetes (Earthworms)
– Few setae per segment
– Head is not well developed
– Locomotion
• Contraction of longitudinal and circular muscles
– Gas exchange is across the body wall
– Feed on leaves and other organic matter
• Food is drawn into mouth by muscular movements
• Digestive tract has a large surface area
Earthworm, Lumbricus
30.4 Annelids: Segmented Worms
• Oligochetes (Earthworms)
– Segmentation in earthworms
• External segmentation evident by body rings
• Internal segmentation by septa
• Ventral nerve cord has ganglionic swellings in
each segment
– Lateral nerves extend from ganglions
30.4 Annelids: Segmented Worms
• Oligochetes (Earthworms)
– Segmentation in earthworms
• Paired nephridia in each segment
– 1 funnel-like opening collects coelomic fluid
– 2nd opening exits through body wall
• Blood moves anteriorly in dorsal vessel
– Enters pumping vessels ”hearts”
– Pump blood to ventral vessel, blood then moves
posteriorly
– Branches in each segment
30.4 Annelids: Segmented Worms
• Oligochetes (Earthworms)
– Reproduction
• Hermaphroditic
– Male organs: testes, seminal vesicles, sperm ducts
– Female organs: ovaries, oviducts, seminal receptacles
• Worms lie parallel in opposite directions
– Clitellum produces mucus to keep sperm moist
» After separation, produces a slime tube which moves
eggs and sperm together for fertilization
» Slime tube then produces a cocoon
30.4 Annelids: Segmented Worms
• Leeches- Class Hirudinea
– Most live in freshwater
– Most are ectoparasites- have suckers for feeding
• Saliva contains hirudin-anticoagulant
– Have same general body plan as other annelids
• Lack setae
• Each body ring has transverse grooves
30.5 Arthropods: Jointed Appendages
• Phylum Arthropoda
– Over 1 million species have been described, over 30
million may exist (mostly insects)
– Appendages are for:
• Walking, swimming, reproduction, eating, sensory reception
– Exoskeleton of chitin (must molt to grow)
– Three body regions
• Head, thorax, abdomen
– Well-developed nervous system
• Brain and ventral nerve cord
• Sense organs
30.5 Arthropods: Jointed Appendages
• Crustaceans
– Barnacles, shrimps, lobsters, and crabs (marine)
– Crayfish (freshwater)
– Sowbugs (terrestrial)
– Known for their hard shells
– Usual anatomy is a pair of compound eyes and five
pairs of appendages
• Front two pairs have sensory functions
• Other three pairs are used in feeding
Male Crayfish, Cambarus
30.5 Arthropods: Jointed Appendages
• Crustaceans
– Internal Organs
• Digestive system– Stomach (Two parts),
– Green glands (waste excretion)
• Vascular system-heart pumps blood with hemocyanin into
hemocoel
– Hemocyanin has blue pigment
– Hemolymph flows around organs
30.5 Arthropods: Jointed Appendages
• Crustaceans
– Internal Organs
• Nervous system-brain and ventral nerve cord with segmental
ganglia
• Sexes separate- sperm transfer by first pair of swimmerets
– Ovaries open at base of third walking legs
– After fertilization, eggs attach to swimmerets of female
30.5 Arthropods: Jointed Appendages
• Insects
– Three body regions
• Head
– Sensory antennae, eyes
– Mouthparts are adapted to each insect’s way of life
• Thorax
– Three pairs of legs and the wings
• Abdomen
– Contains most internal organs
Insect Diversity
30.5 Arthropods: Jointed Appendages
• Insects (ex: grasshopper)
– Internal organs
• Digestive system: stomach, intestine, rectum, anus
• Excretory system: Malpighian tubules
– Nitrogenous wastes are excreted into the digestive tract
• Respiratory system: spiracles lead into trachae
– Air pumped by contraction and relaxation of body wall
• Circulatory system: heart pumps hemolymph into aorta,
leads to a hemocoel
– Hemolymph has no specialized pigment and is colorless
30.5 Arthropods: Jointed Appendages
• Insects (ex: grasshopper)
– Reproduction and Development
• Adapted to terrestrial life
– Male has a penis which is inserted into female
– Female has seminal receptacles which store sperm
– Internal fertilization protects zygotes and gametes from
drying
– Female deposits fertilized eggs into ground
• Metamorphosis: Change in form and physiology that occurs
as a larva becomes an adult
Female Grasshopper, Romalea
30.5 Arthropods: Jointed Appendages
• Comparison of Grasshopper and Crayfish
– Grasshoppers and crayfish share a common ancestry
– Grasshoppers are adapted for terrestrial life, crayfish
are adapted for aquatic life
• Crayfish have gills, grasshoppers have spiracles and trachae
– Crayfish require oxygen-carrying pigment to carry oxygen to
cells
– Oxygen diffuses directly through spiracles and trachae to reach
cells so no pigment needed
• Crayfish excrete liquid nitrogenous wastes (ammonia),
grasshoppers excrete solid wastes (uric acid)
• Grasshopper has tympanum for reception of sound
30.5 Arthropods: Jointed Appendages
• Comparison of Grasshopper and Crayfish
– Grasshoppers are adapted for terrestrial life, crayfish
are adapted for aquatic life
• Male grasshoppers have a penis for passing sperm to female
to prevent drying out
• Crayfish utilize uropods when swimming, grasshoppers have
legs for hopping and wings for flying
30.5 Arthropods: Jointed Appendages
• Arachnids
– Scorpions, Spiders, Ticks, and Mites
• Cephalothorax has 6 pairs of appendages
– Chelicerae, pedipalps, and 4 pairs of walking legs
• Abdomen contains internal organs
• Scorpions
– Oldest terrestrial arthropods
– Abdomen ends with a venomous stinger
30.5 Arthropods: Jointed Appendages
• Arachnids
– Ticks and Mites
• Parasites
– Transmit diseases such as Rocky Mountain spotted fever or
Lyme disease.
– Spiders
• Spiders have a narrow waist that separates cephalothorax
from abdomen
– Chelicerae have fangs that deliver poison to prey
– Book lungs-lamellae of inner body wall for gas exchange
– Silk glands for web-spinning
Arachnid Diversity