bio 2 - animals: the invertebrates ch 31 (post)

what supergroup are animals in?

Opisthokonta in domain Eukarya

what are the two major animal groups?

invertebrates (no backbone) and vertebrates (have backbone)

what is an example of parazoa?

sponges (porifera)

spongin

most sponges have a skeleton composed of fibers of spongin, a soft protein

what is the major evolutionary split in animals?

parazoa (no true tissue) and eumetazoa (true tissue)

relationship between DNA similarity and relatedness - phylogeny

the more closely related two organisms are, the more similar their DNA sequences

what is the major split of eumetazoa

protostomes and deuterostomes

asymmetrical symmetry

No particular symmetry (e.g., sponges)

cnidarian (eumetazoa) organization of sac

• Epidermis (outer)

• Gastrodermis (inner) - gastrovascular cavity with digestive juices

• Layers separated by mesoglea

• the itchy phylum

what are the classes of arthropoda?

1. chilopoda - 1 pairs + 1 body seg

2. diplopoda - 2 pairs = 2 body seg

3. insecta - 3 pairs

4. arachnida - 4 pairs

5. crustacea - 5 pairs

three subphylum of chordata

1. urochordata

2. cephalochordata

3. vertebata chordata

radial symmetry

Circular organization where any longitudinal slice will produce mirror images

• sessile (attached to a substrate) or free floating

bilateral symmetry

• Definite right and left halves—only a longitudinal cut down midline produces mirror images

  • tend to be more active animals

  • often accompanied by cephalization (brain and sensory organs at anterior end)

roundworm male v female difference

males have a curved, hooked posterior end, while females have a straight, blunt posterior end

nematocysts of cnidarians

• toxin filled capsules with coiled thread

  • Discharged when cnidocyte is triggered

  • Used to capture prey

  • Prey is physically captured or paralyzed

spicules

compose internal skeleton of some sponges

ribbon worms - phylum nemertea

• more complex than flatworms

• complete digestive tract

• regional specialization

• closed circulatory system

• blood cells with hemoglobin

• proboscis to capture prey

general features of animals

• locomotion

• multicelular

• life cycle in which adults are typically diploid

• sexual reproductiono

• heterotrophic

sponge reproduction

• Asexual by budding, fragmentation, or gemmule formation (freshwater spore)

• Sexual: most are hermaphroditic, but usually not self-fertilizing

  • •Sperm released through osculum and are drawn into other sponges for fertilization

  • •Zygote develops into a flagellated larva

class chilopoda

phylum arthropoda

1 pair of leg clas/body sec

class diplopoda

phylum arthropoda

2 pair of leg clas/body sec

class insecta

phylum arthropoda

3 pairs of legs

• include female grasshopper - romalea

female grasshopper. romalea

• phylum arthropoda

• class insecta

• digestive system for herbivore diet. they have an excretory, respiratory, and circulatory system metaphorphosis

class crustacean

phylum arthropoda

• marine animals ie barnacles, shrimps, lobsters, and crabs. They are named for their hard shell

function of choanocytes

create water currents and capture food

difference between animals and fungi feeding

fungi: external digestion + absorption

Animals: ingest food and digest internally

which single celled protist is the closest ancestor of animals?

chanoanoflagellates

what is modern animal phylogeny based on?

• morphological characters of living and fossil organisms

• developmental homologies

• molecular DNA characters

choanoflagellates

• A single cell, 3–10 µm in diameter, with a flagellum surrounded by a collar of 30–40 microvilli

• Movement of the flagellum creates water currents, which pull the protist along

• As water moves through the microvilli, they engulf any bacteria and debris

• Can form colonies

evolution of the animal body plan

The animal body plans seen today were present by the Cambrian period, 500 mya.

Two major groups of animals, divided by body plans: invertebrates and vertebrates

invertebrates

• Lack an endoskeleton of bone or cartilage

• Evolved first and far outnumber the vertebrates

vertebrates

Have an endoskeleton of bone or cartilage

what controls variation in animal body plans?

• Different combinations that could have led to the great variety of animal forms

• Slight shifts in DNA code and the expression of Hox (homeotic) genes

symmetry

• asymmetrical

• radial symmetry

• bilateral symmetry

levels of animal organization

cellular, tissue, and organ levels

cellular level of organization

No true tissues

• example: sponges (parazoa)

tissue level of animal organization

• diploblastic - have two germ layers

  • example: Cnidarians like hydra (eumetazoans)

organ level of animal organization

• triplobastic - have an ectoderm, endoderm, and mesoderm - bilateral animals

•Majority of animals (also eumetazoans)

allows for more specialization and abilities

what are the major events that differentiate protostomes or deuterostomes

animals with three tissue layers are differentiated by:

• cleavage

• fate of blastopore formed by blastula

• coelom formation

cleavage - differenitation of animals as protostomes or deuterostomes

•Spiral and determinate in protostomes

•Radial and indeterminate in deuterostomes

Fate of blastopore formed by blastula

• Becomes the mouth in protostomes

• Becomes the anus in deuterostomes

coelom formation - differenitation of animals as protostomes or deuterostomes

•Mesoderm splits in protostomes

•Mesodermal pouches from gut wall meet and fuse in deuterostomes

deuterostomes

• domain eukarya

• supergroup: opisthokonta

• kingdom: animalia

• phylum of eumetazoa

• includes echinoderms and chordates

protostomes

• domain: eukarya

• supergroup: opisthokonta

• phylum eumetazoa

  • divided into ecdysozoa and spiralia

ecdysozoas - types of protostomes

• domain eukarya

• supergroup: opisthokonta

• kingdom: animalia

• have outer covering called a cuticle

• eumetazoa

includes roundworms and arthropods

•Shed outer covering as they grow - molting

spiralia - type of protostomes

• Lophophorans

• platyzoans

• Trochozoans

platyzoans - type of spiralia protostome

• domain eukarya

• supergroup: opisthokonta

• kingdom: animalia

• bilateral symmetry with no circulatory or respiratoy system

key traits of porifera - type of parazoa

sponge and filter feeders

• classified based on their skeleton

• saclike bodies with pores

• lack nerve and muscle cells

• cellular level of organization

• choanocytes (collar cells)

• base of evolutionary tree of animals

  • spicules

    • Chalk sponges have spicules made of calcium carbonate

    • Glass sponges have spicules that contain silica

  • spongin

sponges: the parazoe porfera simple invebrates

• Saclike body with many pores

• Multicellular, but lack organized tissues

• Outer body layer is flattened epidermal cells

• Middle layer is semifluid matrix with wandering amoeboid cells

  • •Amoeboid cells digest food, transport nutrients from cell to cell, and produce sex cells and spicules

• Inner layer is flagellated collar cells called choanocytes

  • •Beating flagella produce water currents that flow in through pores and out through the osculum

filter feeders: the parazoe porfera simple invebrates

• filter water for food and engulf food particles by collar cells

  • •Food is digested or passed to amoeboid cells

• Use asexual and sexual reproduction

the eumetazoa

tissue level of organization

• radial animals (diploblastic) - cnidarians and ctenophores

• Both groups have true tissues

• Their embryos have ectoderm and endoderm germ layers

• can reach in all directions for food

ctenophora - eumetazoe

comb jellies are members of phylum Ctenophora

• Solitary, free-swimming marine animals

• Movie via cilia

• Body made up of mesoglea—transparent, jellylike substance

• Use colloblasts (adhesive cells) to capture prey

• some are bioluminescent

• some have two tentacles

cnidarians - eumetazoe

phylum cnidaria

• Tubular or bell-shaped animals

• Radial symmetry

• All aquatic, mostly shallow coastal waters

• two basic body forms

  • polyps and jellyfish and medusa

• Named for cnidocytes, specialized stinging cells that contain a nematocyst

  • two layer sac

the two basic body forms of cnidarians

polyp

• the mouth and tentacles are directed upward

• The sessile stage produces a medusa by budding

medusa

• bell-shaped with mouth and tentacles directed downward

• Has more mesoglea than polyp

• Tentacles found on the margin of the bell

• Motile form produces egg and sperm

one stage dominant in some species and even absent in others

hydra

• Attaches to rocks and plants in lakes or ponds

• Takes form of a small, tubular polyp, saclike body plan with a single opening (mouth) surrounded by four to six tentacles

• Longitudinal and circular muscle fibers

• Diffuse nerve net below epidermis that communicates with sensory cells throughout the body

• tentacle can reach out and grasp prey

• Digestion begins in the gastrovascular cavity and is completed in the gastrodermal cells

  • nutrients pass to other cells by diffusion

• Gastrovascular cavity also allows exchange of gases with watery medium

• bodies exist only as polyps

• reproduce sexually and asexually

  • sexual reproduction by developing an ovary or testis in body wall

  • asexual reproduction by budding

hydra layers

•Outer tissue layer: protective epidermis derived from ectoderm

•Inner layer: gastrodermis derived from endoderm

•Mesoglea: separates the two layers

sea anemones

cnidaria

• sessile polyps attached to substrate under water

corals

cnidaria

polyps similar to anemones but encased in a calcium carbonate house

hydrozoans

cnidarian

have a dominant polyp stage

•Include hydra and the Portuguese man-of-war

jellyfish

cnidarian

medusa is the primary stage

•Depend on tides and currents for movement

lophotrochozoans

• domain eukarya

• supergroup: opisthokonta

• kingdom: animalia

• eumetazoa protostomia

• spirilia

• Bilaterally symmetrical in at least one stage of development

• Triplobastic

• some have a true coelom

includes: rotifers, flatworms, lophorates, annelids, and mollusks

lophophorans - types of lophotrochozoa

• domain eukarya

• supergroup: opisthokonta

• kingdom: animalia

• spiralia protostomes

• have a mouth surrounded by ciliated tentacle-like structures

include: bryozoans, phoronids, brachiopods - aquatic; have lophophore mouth

trochozoans - types of lophotrochozoa

protostomes

all have trochophore as a larval stage; also includes flatworms and rotifers because they descended from an ancestor of a trochophore in the past

bryozoans - lophophorans

• domain eukarya

• supergroup: opisthokonta

• kingdom: animalia

• aquatic, colonial lophophorans

•Zooids are individuals in a colony and have protective exoskeletons; can specialize

brachiopods - pohpophorans

have two hinged shells

•Top and bottom shells; muscular pedicle affixes to hard surfaces

phoronids - lophophorans

live inside a long tube formed from their own chitinous secretions

mollusks - trochozoans inside of lophotrochozoans

phylum mollusca

• domain eukarya

• supergroup: opisthokonta

• kingdom: animalia

• Second most numerous animal phylum

• Variety of environments: marine, freshwater, terrestrial

• true coelom with bilateral symmetry

• three germ layers

• organ level of organizaiton

• complete digestive tract

Chitons, limpets, slugs, snails, abalones, conchs, nudibranchs, clams, scallops, squid, and octopuses

unique characteristics of mollusks

Visceral mass: soft body mass that includes most organs

Foot: muscular portion used for locomotion

Mantle: membranous or muscular covering that almost encloses visceral mass

• Mantle cavity—space between the two folds of mantle

• Mantle may secrete a shell

• Radula—rasping, tonguelike organ for feeding

flatworms - trochozoan lophotrochozoa - protostomes

phylum Platyhelminthes

• Incomplete digestive tract (gastrovascular cavity) with one opening (mouth)

• No body cavity—mesoderm fills spaces between organs

• Lack respiratory and circulatory systems

• free living planarians - •Have muscles, excretory, digestive, and nervous systems

• Parasitic flukes and tapeworms

free living flatworms

• freshwater planarians - Found in lakes, ponds, and streams

  • •Feed on small organisms such as worms and crustaceans by extending muscular pharynx

• Possess an excretory system of canals and flame cells

  • Ladderlike nervous system exhibits cephalization (small brain, eyespots)

• Reproduce both asexually and sexually

gastropods - mollusks

class gastropoda

• Includes nudibranchs, conchs, and snails

• Foot is flattened ventrally

• Move by muscle contractions along the foot

• Some herbivores; others carnivores

• Existence of shells varies

• Land snails hermaphroditic; cross-fertilize

cephalopods - mollusks

class cephalopoda

• Includes octopuses, squid, nautiluses

• Foot has evolved into funnel or siphon

• Powerful tentacles, beak, and radula used for feeding; ink defense

• Cephalization

• Octopuses have no shell; squid have reduced shell

bivalves - mollusks

class bivalvia

• Include clams, mussels, oysters, scallops

• Two-part shells composed of protein and calcium carbonate are secreted by mantle

• Gills located within the mantle cavity, used for gas exchange

• Filter feeders: water enters through incurrent siphon

• “Hatchet” foot can extend and move clam

• visceral mass

• The sexes are usually separate

  • Gonads (ovary or testis) are located around coils of intestine

• All clams have some type of larval stage, and marine clams have a trochophore larva

bivalves visceral mass - mollusks

• The heart lies within the pericardial cavity, which is the only remains of the reduced coelom

• The open circulatory system is so called because blood flows through sinuses in the organs

• The nervous system is composed of three pairs of ganglia connected by nerves

• clams lack cephalization

bivalves digestive system - mollusks

• includes a mouth with labial palps, esophagus, stomach, and intestine.

• Two excretory kidneys remove waste from the pericardial cavity

the two basic body forms of cnidarians

polyps have mouths directly up but for jellyfish and medusa they are directed down

• medusa are bell shaped and have more mesoglea than a polyp and tentacles are concentrated on the margin of the bell

  • when both are present the animal is dimorphic: the sessile polyp stage produces a medusa by asexual budding and the motile medusa stage produces an egg and sperm - in some one stage is dominant and the other is reduced but in other species one form is absent all together

annelids

• phylum annelida

• segmented - rings on outside of body

• developed coelom

• septa separated segments

• hydrostatic skeleton - fluid filled interior - muscle contraction and stretching

• losed circulatory system

• locomotion via contraction and expansion

• specialization of digestive tract

• closed circulation system

• nervous system of nerve cord

• nephridia tube for excretion

• includes leaches and worms as well as marine animals

polychaetes

1. marine annelids

• have many setae - bristles that anchor the wormm and help it to move

  • setae are on parapodia which are used for swimming and respiration

• have head and sense organs

• predator

2. sessile tube worms with tentacles to form fan

• Cilia create water currents to direct trapped food toward the mouth

• sex organs are functional only during breeding seasons

  • Zygote develops into a trochophore larva

oligochaetes

class oligochaeta

phylum annelida

• includes earthworms

• few setae

• no well developed head or parapodia

• locomotion via muscle contraction in segments

• need moisture for gas exchange

• scavengers

• use muscular pharynx to eat

• digestion through long intestine called typhlosole

• •Long ventral nerve cord; brain

• •Dorsal and ventral blood vessels; five pairs of connectives called “heart”

• segmentation: body rings, nerves in each segments, coelom divided by septa

• reproduction: hermaphroditic

leeches

class hirudinea

phylum annelida

• mostly found in freshwater

• same body plan as other annelids but no setae and body rings have grooves

• two suckers - one around the mouth and one posterior one

• fluid feeders at open woods or free living feeding on plants

• hirudin in saliva prevents blood coagulation for those that feed on blood

free living flatworms reproduction

• regeneration (asexual)

• hermaphroditic cross fertilization (sexual)

the two types of parasitic flatworms

1. tapeworms - class cestoda

2. flukes - class trematoda

tapeworms - parasitic flatworms

• class cestoda

• internal parasites with specialized body covering resistant to digestive juices

• excretory, muscular, and nervous systems similar to those of other flatworms

• scolex - anterior region with hooks for attachment and suckers for feeding

• proglottids - reproductive units - body segments

• taenia solium - uses a human as a primary host and a pig as a secondary host

flukes - parasitic flatworms

• class trematoda

• endoparasites

• Body is flattened, oval to elongated, with a nonciliated integument

• Two suckers: one for feeding, one for attachment

• Well-developed alimentary canal

• Muscles and excretory system similar to free-living flatworms

• Reduced nervous system (poorly developed senses)

• Often hermaphroditic

• Complex life cycle involving two intermediate hosts

Blood, liver, and lung versions

rotifer

• phylum rotifera

• trochozoans related to flatworms

• crown of cilia - corona → used for locomotion and to move food to the mouth

• many are transparent

• can desiccate to survive harsh conditions and remain dormant for long times

roundworms - phylum Nematoda

phylum Nematoda

• Nonsegmented worms found in almost every environment

• have a pseudocoelom—a fluid filled body cavity that is incompletely lined by mesoderm - substitute for circulatory system

• nematodes (phylum) can be free-living or parasitic

• scaris lumbricoides

  • females are longer and prolific

  • whiplike motion

  • Eggs enter host in uncooked vegetables or ingested fecal material

• trichinosis from undercooked pork and resides in intestine after ingestion

• lympathatic filariasis - caused by filarial worms which use mosquito as intermediate host and resides in lymphatic vessels and prevent lymph drainage

  • pinworms are common in US kids

arthropods

phylum Arthropoda

• many species

• characteristics:

  • segmentations - fused to form head, thorax, abdomen regions

  • jointed appendages

  • •Exoskeleton composed of chitin; must be shed (molting) to grow larger

  • well developed nervous system, sensory structures, simple and compound eyes

  • respiratory organs

  • metamorphosis

crustaceans - types of arthropods

(subphylum Crustacea)

• largely marine arthropods such as barnacles, shrimp, lobster, and craps

• freshwater: crayfish

• terrestrial: sowbug

• named for hard shell - calcified exoskeleton

• head with eyes and have five pairs of appendages - firs two are antennae and others are feeding mouthparts

• stomach with two parts - one for grinding and one for filtering

• green glands in head excrete metabolic waste

• coelom is reduced

• nervous system similar to earthwroms

• hemocoel - gives blue color to blood - open circulatory system

• separate sexes

crayfish - crustaceans

• Five pairs of walking legs on thorax

• gills above the walking legs

• Head and thorax fused to form cephalothorax - covered by carapace

• Abdominal segments have swimmerets - paddlelike structures

• Last two segments are the uropod and telson which make fan shaped tail

insects - types of arthropods

subphylum Uniramia

• head with sensory antennae, compound or simple eyes, and mouthparts

• abdomen

  • digestive system

  • extetory system - malpighian tubules

  • respiratory system - spiracle openings lead into tubules called tracheae that branch - air pumped via contraction and relaxation

  • circulatory: heart pumps hemolymph into aorta, leads to a hemocoel (no pigment here though)

• thorax with three pairs of legs and zero to three pairs of wings

entomology

the study of insects

reproduction and developement of insects

• Reproduction is adapted to life on land

  • Internal fertilization protects both gametes and zygote from desiccation

  • Sperm is released by a male from a penis, passed to the female, and stored in the seminal receptacle

• Metamorphosis

  • Change in form and physiology that occurs as an immature stage, called larva, becomes an adult

  • grasshoppers go through gradual

  • caterpillar go through complete

comparison of crayfish and grasshoppers

• Adaptations:

  • Grasshoppers → terrestrial life

  • Crayfish → aquatic life

• Respiration:

  • Crayfish → gills + oxygen-carrying pigment

  • Grasshoppers → spiracles & tracheae (oxygen diffuses directly; no pigment needed)

• Excretion:

  • Crayfish → ammonia (liquid waste)

  • Grasshoppers → uric acid (solid waste)

• Movement:

  • Crayfish → swim using uropods

  • Grasshoppers → move with legs and wings

• Sensory & Reproduction (Grasshoppers):

  • Tympanum for hearing

  • Males have penis (prevents sperm from drying out)

  • Females have ovipositor (lays eggs)

arachnids

(subphylum Chelicerata)

• Scorpions, spiders, ticks, and mites

• Cephalothorax has six pairs of appendages → Chelicerae, pedipalps, and four pairs of walking legs

  • abdomen has internal organs

scorpions - arachnids - arthropods

• Pedipalps are large pinchers

• Long abdomen ends with a venomous stinger

• Widely distributed, tropics, subtropics, and temperate regions

spiders - arachnids - arthropods

• Narrow waist separates cephalothorax from abdomen

  • •Chelicerae have fangs that deliver venom

  • •Book lungs are used for gas exchange

  • •Silk glands are used for web spinning

  • internal organs reflect adaptation

    • Malpighian tubules work in conjunction with rectal glands to reabsorb ions and water

    • A relatively dry nitrogenous waste (uric acid) is excreted

    • Invaginations of inner body wall form lamellae, which create the book lungs

invertebrate deuterostomes

• Chordates are most closely related to echinoderms

• second embryonic openin becomes mouth

• coelom forms via outpocketing of primitive gut

echinoderms - invertebrate deuterostomes

• Marine

• Endoskeleton made of spine-bearing, calcium-rich plates

• Spine sticking out of skin

• Radial symmetry

  • •Larvae are bilateral free swimmers, which undergo metamorphosis into radially symmetrical adults

• includes: sea lilies, motile feather stars, brittle stars, and sea cucumbers

sea stars - echinoderms - invertebrate deuterostomes

• mouth on underside and anus on upperside

• On the oral surface, each arm has a groove surrounded by tube feet

• spines for protection

• Pincerlike structures called pedicellariae that keep the body surface free of debris

• Skin gills, extensions of skin, for gas exchange

• feeding on clams, oysters, and other bivalve mollusks

  • partial digestion inside and out

• NS: central nerve ring on each arm and eyespot at tip of each arm

• locomotion: uses water vascular system

  • Water goes in → through tubes → into tiny feet

  • Water pressure makes the tube feet stretch out

  • The feet stick to surfaces (like suction cups)

  • Then they pull the animal forward

• no respiratory, excretory, or circulatory systems exist

• sexual and asexual reproduction

Clonorchis sinesis Microse pic