Bio2: Final Exam -Mary Susan Potts Santone Biol1113

Lophotrochozoa

clade of protostomes that exhibit a trochophore larvae stage or a lophophore feeding structure

Members generally have either

A lophophore (a crown of ciliated tentacles)

- Bryozoans, Brachiopods

-

Or a trochophore larval stage

- Molluscs, Annelids

-

•Molecular evidence also includes

-Rotifers, which have a lophophore-like feeding device

-Platyhelminthes, some of which have trochophore-like larvae

lophophore

a crown of ciliated tentacles that function in feeding

trocophore

a free-swimming, ciliated larva of many worms and some mollusks

Rotifers

tiny animals that inhabit fresh water, the ocean, and damp soil, which have a lophophore-like feeding device

Platyhelminthes - Flatworms

flatworms

Majority are parasitic (80%)

Organ-level organization

No specialized circulatory or

respiratory structures

Cephalization

Bilateral symmetry

Ladder-type nervous system

Platyhelminthes - Turbellarians

free-living flatworms:

Planarians - Live in freshwater habitats

Head is bluntly arrow shaped

Auricles = sense organs

Two light-sensitive eye spots

Three kinds of muscle layers:

Outer circular layer

Inner longitudinal layer

Diagonal layer

Excretory organ functions in osmotic regulation and water excretion

Asexual

Hermaphroditic

3 muscle layers of turbellarians

Outer circular layer

Inner longitudinal layer

Diagonal layer

excretory organ functions - flatworm

osmotic regulation and water excretion

types of parasitic flatworms

Flukes and Tapeworms

Flukes: Trematodes

Reproductive system well developed

Usually hermaphroditic

Complex life cycle

Tapeworms: Cestodes

Platyhelminthes - Cestodes

Tapeworms:

•Have anterior region with modifications for attachment to intestinal wall of host (scolex)

• Body - Long series of proglottids

Each segment contains a full set of male and female sex organs

Self-fertilize

Complicated life cycles

Rotifera

Rotifers - 2,200 spp.

Named for crown of cilia resembling a rotating wheel (Corona)

Serves as both as an organ of locomotion and aids direction of food to mouth

Mastax = pharynx

Trophi = jaws for grinding

Abundant in freshwater

Pseudocoelomate

mastax

the muscular pharynx in rotifers

Trophi

jaw-like structures in pharynx, grind food collected by the corona

Parthenogenesis

reproduction from an ovum without fertilization, especially as a normal process in some invertebrates and lower plants.

Women only!!

Annelida +DTS

segmented worms:

Segmented partitions (septa) divide the well-developed, fluid-filled coelom, which acts as hydrostatic skeleton

Specialized digestive tract

Closed circulatory system

- Double transport system: Circulatory system

and coelomic fluid both carry nutrients, wastes

and respiratory gases

Ventral solid nerve cord

-Giant axons facilitate rapid responses

Most are marine

Chaetae (bristles) - help in movement

Polychaetes, Oligochaetes, Leeches,

chaetae

Bristle-like extensions found in some annelids - help in movement

Polychaetes, Oligochaetes, Leeches,

Major Annelidan Groups

Errantia and Sedentaria

+ Tube worms/Earthworms/Leecches

Errantia

- Long chaetae on footlike parapodia

- Most are free-ranging predators

- Well-developed eyes, powerful jaws

- Often brightly colored

Sedentaria

- Chaetae close to body wall to facilitate anchoring in burrows

Polychaetes

A class of annelids that have parapodia, ridgelike structures that help it move. The parapodia have numerous chaetae and can also function as gills.

Prostomium, Peristomeum, Parapodia, Many chaetae

Pogonophora (Siboglinids)

•Anterior cephalic lobe, bearing a beard of 1 - 1000's ciliated tentacles

• Trunk with pair of coelomic cavities

• Gut tissue forms an organ (trophosome) that becomes filled with chemosynthetic bacteria

• Segmentation confined to small rear portion (opisthoma)

• Habitat - Near Hydrothermal Vents

Oligochaetes

Do not have well-developed head or parapodia

Chaetae protrude in pairs directly from surface of body

Food drawn into mouth by action of muscular pharynx

Digestion and absorption occur in long internal intestine (Typhlosole for absorption)

Closed circulation

Reproduction - Hermaphroditic

Clitellum - secretes 1) mucus to protect sperm from dessication and 2) the cocoon

Direct Development

Hirudinea

Leeches:

Usually found in fresh water

Same body plan as other annelids

(dorsally flattened)

• No chaetae; No head

• Muscular body wall

• No peristalsis

• Two additional suckers

Some temporarily parasitic

Mollusca Phylum - 3 part body plan

• Visceral Mass - Contains internal organs

• Mantle - May secrete shell and/or contribute to development of gills or lungs

• Head-Foot - Muscle adapted for locomotion, attachment, or food capture, sensory reception

mollusca nervous system

•Nervous system consists of several ventral ganglia connected by nerve cords

mollusca Coelom

Coelom is reduced, and largely limited to the region around the heart

mollusca heart

• Heart pumps hemolymph through vessels into hemocoel (Open circulation)

Hypothetical Ancestral Mollusc

This idea suggests that the diversity of molluscs came about modifications from a single ancestor. All molluscs the same body plan plus or minus a few characteristics but modified in diverse ways.

Bivalves examples

Clams, Oysters, Mussels, and Scallops

Bivalves characteristics

•Shell of two hinged parts, closed by powerful muscles (adductors)

• No head, no radula

• Circulatory system open

• Sexes are separate

• Ciliated gills hang down within mantle cavity on either side of visceral mass

Beating of cilia causes water to enter cavity

Capture tiny food particles suspended in water

Gastropods examples

Snails, Slugs, Nudibranchs, Limpets

Gastropods characteristics

•Have elongated, flattened foot

• Well-developed head region

• Eyes and tentacles project from coiled shell

• Gills are found in mantle cavity in aquatic gastropods

• Mantle functions as lung in terrestrial gastropods

Torsion

esophagus twists taking anus from back to front

Cephalopods examples

Nautilus, Cuttlefish, Squid, Octopus

Cephalopods characteristics

•Head Footed - Force water out mantle cavity (Jet propulsion)

• Tentacles and arms capture prey by adhesive secretions or suckers

• Beak used to tear prey apart

• Well-developed sense organs

• Closed circulatory system

•Spermatophore passed from males to females (Hectocotylus)

• Chromatophores

Ecdysozoa

Supergroup of protostomes; characterized by periodic molting of their exoskeleton. Include the roundworms and arthropods.

•Separation from Lophotrochozoa supported by both molecular data and morphology

•Named for Ecdysis - Molting

•A cuticle provides support and protection

•Some species undergo metamorphosis

•Internal fertilization; amoeboid sperm

-Allows colonization of dry environments

•Of the 8 phyla, Nematodes and Arthropods are most common

Ecdysozoa - Nematodes

• Tiny, ubiquitous, unsegmented worms that possess a cuticle made of collagen

• Most are free-living predators but many are parasitic

• Some parasitic roundworms block lymphatic ducts and cause elephantiasis

•20,000 described nematode species

(4-50x's = actual diversity)

• m2 of coastal mud yields 4.4 million

• One decomposing apple in an orchard contains 90,000

• Majority of nematodes are small predators or saprophytes (they eat decomposing organic matter)

Nematoda

Roundworms:

Non-segmented, generally colorless worms

Larger ones - Pseudocoelomate

Parasitic roundworms infect humans, animals, plants

Homogenous morphology

Molt cuticle

Eutely

Only longitudinal muscles

Hookworm

a parasitic roundworm found in the intestines of mammals

Infects >1/2 billion people worldwide

~1/5 world's population

Parasitic Nematodes

Guinea worm, Elephantiasis, Pinworm, Heartworm, trichinosis, River blindness

Arthropoda

Arthropods have freely movable jointed appendages

Very successful due to many characteristics

Rigid, jointed exoskeleton - Chitin

Must molt as they grow

Segmented, fused

(tagamata)

Head, thorax, abdomen

Arthropods

• Versatile Exoskeleton - highly protective + mobile

• 1 pr appendages/segment

• Growth by molting (ecdysis)

Well developed Organ Systems

Digestive System - suspension feeders, predators, scavengers, herbivores (wide variety of mouth parts)

Foregut, Midgut, Hindgut; 2 Part stomach (Gastric mill)

Variety of respiratory organs

Gills, Book lungs, Tracheal System

•Excretion - Green gland,

Malpighian tubules

Open Circulatory system

Separate Sexes; Metamorphosis

Arthropods - Crustaceans

Shrimp, lobsters, crayfish, crabs, barnacles

Thorax bears 5 pairs of walking legs (biramous)

- 1st pr = Chelipeds

Head and thorax fused into cephalothorax

Covered by nonsegmented carapace

2 prs. Antennae

1 pr. Compound eyes

Abdominal segments with swimmerets; tail = uropods

Respiratory system - gills

chelipeds

first pair of legs in crayfishes that bear large claws that are modified to catch, pick up, crush, and cut food

carapace

shell covering the back (of a turtle, tortoise, crab, etc.)

swimmerets

small leg-like structures under the tail of the crayfish

Arthropods - Chelicerates

Spiders, Scorpions, Ticks, Mites, Horseshoe Crabs Sea Spiders (74,000; largely terrestrial)

All appendages attached to cephalothorax; none on head

First pair (chelicerae) are feeding organs (fangs)

Second pair (pedipalps) function in feeding or sensory

Arthropods - Uniramians

Hexapoda (Insects) and Myriapoda (Millipedes, and Centipedes)

> 1,000,000 spp.

Appendages attached to the thorax and abdomen only have one branch (uniramous)

3 prs. of legs, 0 - 2 prs. wings

Head appendages include:

Only one pair of antennae

One pair of mandibles, and

One or two pairs of maxillae

Live on land and breathe by tracheae

Chilopods vs Diplopods

centipedes vs millipedes

Chilopods:

•3,000 spp.

• Flattened dorsoventrally

• Fast Carnivores

• Poison glands

Diplopods:

Diplopods = Millipedes

• 10,000 spp.

• Rounded body

• Slow-moving deposit feeders

Ametabulous

Ametabolous = No metamorphosis

Change little in form as they develop;

Just keep getting larger

Wingless

• Bristletails

• Springtails

• Silverfish - eat paper, fabric, cereal

photos, glue

Firebrats

Hemimetabolous

Gradual (incomplete) metamorphosis

Dragonflies, damselflies, stoneflies, mayflies, grasshoppers, cicadas, cockroaches, termites

Holometabolous

Complete metamorphosis - most insects

Tardigrada

water bear

•1000 spp.

• Very small - 0.3 - 0.5 mm

• Mosses, surface films, aquatic algae, barnacles

• Short, plump cylindrical body

• 4 prs. Stubby legs with claws (lobopods)

• Stylet apparatus

• Dorsal brain, ganglionated nerve cord

• Malphighian tubules

• Dioecious, singular gonad

• Mating/egg laying during molting

• Direct development

Cryptobiosis - "tun

Common characteristics of animals

§Multicellullarity - GKPID

§ Heterotrophs - diverse modes

§ No cell walls: flexibility

§ Nervous tissue: rapid response

§ Muscle tissue: movement

§ Sexual reproduction

- small, mobile sperm; larger egg

- diploid from a blastula

- Metamorphosis

§ Extracellular matrix: collagen

§ Special clusters of Hox genes: patterns body axis

§ Similar rRNA

§ Characteristic cell junctions: anchoring, tight, gap

History of Animal Life

•Multicellular animals emerged at the end of the Proterozoic eon (over 600 mya)

•First animals were invertebrates

•A sudden increase in animal diversity occurred during the Cambrian explosion (533-525 mya)

•Three possible explanations

§Favorable environment - warm temperatures, increases in atmospheric and aquatic oxygen, development of ozone layer

§Evolution of the Hox gene complex

An evolutionary "arms race"

vertebrate evolution

•Fishes, the 1st vertebrates, arose ~520 mya

•Plants colonized land around the same time

-Provided a food source for animals on land

•Life on land presents important challenges

-Animals developed lungs, internal fertilization, amniotic egg

•Reptiles dominated the Earth for millions of years

-Dinosaurs died out ~65 mya, giving way to an explosion in the number and diversity of mammals

2 types of animals

Invertebrates

• Without a backbone

• 97 - 99% of all animals

• Heterogeneous assemblage

of groups (>35 phyla; discuss ~12)

• No single positive character in common

• Examples: sponges, jellyfish, "worms," crustaceans, insects, clams, snails, sea stars

Vertebrates

• With a backbone

• 1% of all animals

• 1 phylum (Chordata)

• Examples:

fish, frogs, birds, reptiles, mammals, humans

invertibrates

ªAnimals without a backbone

ª 96% of all described species of animals

ª Heterogeneous assemblage of groups (>35 phyla)

ª No single positive character in common

ª Gateway to diversity of animal life

why study invertibrates?

Direct/Indirect cause of many human, animal, plant diseases

At/Near base of most food webs in all habitats

Have provided much of our current knowledge of:

Gene expression, Cell division, Aging, Apoptosis, Embryonic Development, Fertilization, Hemoglobin, Chemoreception, Nerve Impulses, Learning, Memory, Vision, etc.

Animal Behavior, Ecology, Physiology, Evolution

Source of Unique Chemicals,

Commercial Products

Pest Control, Invasive species

Indicators of Environmental Health

Biodiversity

Phylum Porifera

Sponges

•Only level of animal to have cellular organization (Parazoa)

• Saclike bodies perforated by many pores (ostia)

• Beating of flagella (choanocytes) produces water currents that flow through pores into central cavity and out osculum

• Sessile filter feeders

Asexual reproduction by fragmentation or budding

ostia

The intake pores on a sponge

Choanocytes

Collar cells that line the body cavity and have flagella that circulate water in sponges

3 types of sponges

asconoid, syconoid, leuconoid

Asconoid

Small, tube-shaped

Flagellated Spongocoel

bath sponge

syconoid

Tubular body

Flagellated Canals

glass sponge

Leuconoid

Most complex, largest

Large colonial masses

Flagellated Chambers

barrel sponge

Cnidaria

Tubular animals that most often reside in shallow marine waters

• Tissue level of organization; Diploblastic

• Radial symmetry

• Polyp and medusa body forms

• Specialized stinging cells (cnidocytes)

- Fluid-filled capsule (cnidae), with nematocyst

• Two-layered body sac

-Outer layer - Protective epidermis

- Inner layer - Gastrovascular cavity

Nerve net found throughout body

Cnidarian Diversity

Scyphozoa - "jellyfish"

• Medusa; thick mesoglea

• Float in open sea

• Manubrium with oral lobes

• Stomach with pouches

• Sense organs = rhopalium

(statocyst + ocelli)

• Separate sexes

Cubozoa- box jellies

Hydrozoa

Marine and freshwater

A colony of polyps enclosed by a hard, chitinous covering

Feeding polyps (gastrozooid)

Extend beyond covering

Have nematocyst-bearing tentacles

Reproductive polyps (gonozooid)

Budding of new polyps

Also has sexual reproduction (medusae) stage

Anthozoa

- flower animals

• Polyp; No medusa

• Sea anemones, hard corals, sea fans

• Large gastrovascular cavity with septa

• Ciliated groove - siphonoglyph

• Circular and longitudinal muscles

• Attachment by pedal disk

• Pedal laceration

• Potent nematocysts/Acontia

• Coral reefs - Hermatypic corals

Calcareous cups secreted by polyps

Zooxanthellae

medusa

A free-swimming cnidarian with a bell-shaped body and tentacles

Coral Reef

A structure of calcite skeletons built up by coral animals in warm, shallow ocean water.

Home to 25% of ALL Marine Life!

Coral Reef disturbances

Bleaching - Loss of Zooxanthellae Death of coral

1998 - 16% of the world's reefs destroyed (El Niño/La Niña pattern)

2005 - 80% bleached w/ 40% death across wider Caribbean

2010 - SE Asia, Indian Ocean: 50% cover reduced to 10% (pool superhot water)

Causes: disease, sedimentation, pollutants and changes in salinity, exposure, predation, physical contact

Also: Temp, Climate change, ocean acidification

Ocean Acidification

decreasing pH of ocean waters due to absorption of excess atmospheric CO2 from the burning of fossil fuels

some species benefit while others decline

Great Barrier Reef

Great Barrier Reef Coral Bleaching Restarts

(For 5th Year In A Row)

"Only an End to Global Warming Can Save the Great Barrier Reef"

Half of the Great Barrier Reef has been bleached to death since 2016. (Aug 2018)

Great Barrier Reef suffers 89% collapse in new coral and change in coral types after bleaching events (2019)

5 mass bleaching events since 1998

# baby corals has dropped dramatically

The Reef is valued at $56 billion

"The Great Barrier Reef is dying

World's biggest single structure made by living organisms.

Ctenophora

Comb Jellies - all marine

• 8 comb rows = ctenes; covered by long cilia

• 2 long tentacles; Colloblasts

• Fragile, transparent body

• No nematocysts

• Apical sense organ

• Voracious appetite

• Bioluminescence

•First complete gut - mouth and two anal pores

Hermaphroditic

Basal, No Hox genes?

Vertebrates

Chordates with a Backbone

Chordate characteristics

1.Vertebral column

2.Cranium

3.Endoskeleton of cartilage or bone

wIntegument - epidermis + dermis

wMany muscle

wComplete GI tract

wVentral heart, closed circulation, RBC's with Hb, 2 circuits

wWell-developed coelom

•Paired kidneys

•Brain w/ 10-12 prs. Cranial n.

•Endocrine system

•Separated Sexes

•Body plan - Head, Trunk, Tail

•Multiple clusters Hox genes

Cyclostomata - Hagfish

Hagfishes - "Slime eels"

70 species - Marine

Lack eyes, jaws, fins, and vertebrae

Cartilagenous skull + notochord

Scavengers

Blind, Keen smell and touch

Live in burrows on bottom

Rasping tongue

Enormous quantities of slime

Cyclostomata - Lampreys

Marine and freshwater

Naked skin, dorsal fins

Notochord and rudimentary vertebral column

Parasites on fish

Well-developed eyes

Sucker-like Oral disk

Rasp prey, suck body fluids; anticoagulant

3 - 17 yrs Ammocoetes

Gnathostomes

Jawed Vertebrates

•Jaws allowed more efficient prey capture

- Accompanied by development of 2 pairs of appendages

Hinged jaws developed from gill arches

Two pairs of gill arches were lost, others were modified

Fish

Gill-Breathing, Ectothermic, Aquatic Vertebrates with Paired Fins and Skin with Scales

Chondrichthyes

Cartilagenous Fishes

like sharks , 1,000+ species, Ancient, Cartilagenous Skeleton (derived), Moveable, Powerful Jaws, with Teeth, 5 - 7 Gill slits, Well, developed, Sense organs, Fusiform body, Heterocercal Tail, Pelvic and pectoral fins, Placoid, Scales, Denser than water

Chondrichthyes include

Shark, Sandbar shark/great white, spiny dogfish, rays, filter feeder

shark features

•Heterocercal Tail

(caudal fin)

•Placoid Scales

• Teeth with dentin and enamel; replaceable

• 1st two rows active

Chondrichthyes sensory systems

•Ampullary organs of Lorenzini = Bioelectric organs

•Lateral Line System

Neuromasts; vibration and current

w2/3 of brain dedicated to smell

Chondrichthyes other features

•Lack Swim Bladder; Heavier than water,

large liver with squalene

•Blood Iso-osmotic - Urea, Trimethylamine oxide

•Separate Sexes; Internal Fertilization; Clasper

•Direct Development

oviparous, ovoviparous, viviparous

Oviparous - lays eggs

Also rays, mermaid's purse

Ovoviparous - bear young alive,

develop in ovarian cavity

Viviparous - bear live young;

placenta; also skates

Sharks on the Decline

Shark fin soup - served since Ming dynasty

(1368 to 1644)

Asian delicacy (primarily China - 95%)

- China has banned it from State functions

$100.00/bowl (70 - 100 million sharks/yr)

$450 per pound on the Hong Kong market.

Shark finning banned:

US, Mexico, Ecuador, Australia, Canada, EU

Shark fin trade banned in 12 U.S. states + 3 territories

A single Whale Shark pectoral fin can sell for up to $20,000 USD and a Basking Shark pectoral fin can fetch up to $50,000 USD.

Shark populations have declined as much as

90% or more in the last 50 years (100 spp endangered)

Osteichthyans

Includes all vertebrates with a bony skeleton

Bony fishes are most numerous of all fishes

Two living clades: > 25,000 species

Actinopterygii - ray-finned fishes

Sarcopterygii - lobe-finned fishes

Bony skeleton and scale-covered skin

Operculum covers gills

swim bladder for buoyancy

Most species reproduce via external fertilization

Specialization of jaws and feeding mechanisms

Cartilagenous vs. Bony fishes

Chondrichthyes:

- Cartilage only

- Forward only

- Large oily liver

- Slits but no gill cover

- Internal fertilization

- Rough, sand-paper like placoid scales

Bony fish:

- Cartilage and bones

- Forward and backward

- Gas-filled swim bladder

- Covered gill slits

- Eggs usually fertilized externally

- Smooth, overlapping scales, mucus

Actinopterygii

ray-finned fishes:

includes nearly all the familiar aquatic osteichthyans. fins are supported mainly by long, flexible rays.

Fins supported by thin, bony, flexible rays

Lionfish, clownfish, sunfish, pufferfish, sea horse

Fish Tails

Larger fish = faster swimmer

Sickle shape tail = faster

Swimming is energetically economical

Sailfish - fastest fish

Can leap out of the water at more than 68 mph.

Fish scales

overlapping plates that protect the fish

Ganoid: Primitive Bony

Fishes (i.e. Gar)

Diamond shape,

Heavily armored,

Not overlapping

Placoid: Cartilagenous fishes

Cycloid: Salmon/Carp

Ctenoid: Perch

Modern Teleosts

Arranged in overlapping

Rows, Light, flexible,

Comb-like ridges

teleost

group of bony fishes with highly mobile fins, thin scales, a swim bladder, and symmetrical tails; largest group of living fish

Fish anatomy

Swim bladder - neutral buoyancy

Present in most pelagic bony fishes

Absent in tuna, flounder

Pneumatic duct - connects bladder to esophagus --> gulp air

Gas gland and Reabsorption area; capillaries = Rete mirabile

Respiration via Gill

Thin filaments, many folds = Lamellae

Covered and protected by Operculum

Countercurrent Flow

Osmoregulation - Marine teleost

Hypo-osmotic Regulators

Problem: lose water,

gain salts

Risk for dehydration

Solution: drink seawater, excrete salts across gills

Osmoregulation: Freshwater teleost

Hyperosmotic Regulators

Problem: water enters by osmosis, salt lost by diffusion

Risk of drowning

Solution: Scales and mucus, Water pumped across kidney; Salt absorbing cells in gills

Sarcopterygii

Lobe-Finned Fishes

•Includes tetrapods

•Fins supported by skeletal extensions of the pectoral and pelvic areas and moved by muscles

Tetrapods

Amphibians + Amniotes (Reptiles, Birds, Mammals)