intro to invertebrates

Question 1

animals that lack a backbone

Answer 1

invertebrates

Question 2

-informally known as sponges
-are filter feeders
-lack true tissues and organs
-consist of a gelatinous noncellular mesohyl layer between two cell layers

Answer 2

Porifera

Question 3

capturing food particles suspended in the water that passes through their body

Answer 3

filter feeders

Question 4

Water is drawn through pores into a cavity called the _______ and out through an opening called the _______

Answer 4

spongocoel, osculum

Question 5

flagellated collar cells, generate a water current through the sponge and ingest suspended food

Answer 5

choanocytes

Question 6

are found in the mesohyl and play
roles in digestion and structure

Answer 6

amoebocytes

Question 7

Sponges consist of a gelatinous noncellular ______ layer between two cell layers

Answer 7

mesohyl

Question 8

-have diversified into a wide range of both sessile and motile forms including jellies, corals, and hydras
-exhibit a relatively simple diploblastic, radial body plan
-are carnivores that use tentacles to capture prey
-2 major clades: Medusozoa, Antozoa

Answer 8

cnidaria

Question 9

basic body plan of a cnidarian is a sac with a
central digestive compartment

Answer 9

gastrovascular cavity

Question 10

adheres to the substrate by the aboral end of its body

Answer 10

polyp

Question 11

has a bell-shaped body with its mouth on the underside

Answer 11

medusa

Question 12

tentacles are armed with this, which are unique cells that function in defense and capture of prey

Answer 12

cnidocytes

Question 13

are specialized organelles within
cnidocytes that eject a stinging thread

Answer 13

nematocysts

Question 14

-include all cnidarians that produce a medusa; jellies, box jellies, hydrozoans
- predominant stage in the life cycle
of most scyphozoans and cubozoans

Answer 14

medusozoans

Question 15

-includes the corals and sea anemones
-occur only as polyps

Answer 15

anthozoans

Question 16

external skeleton

Answer 16

exoskeleton

Question 17

-was identified by molecular data
-includes flatworms, rotifers, ectoprocts, molluscs, annelids

Answer 17

lophotrochozoa

Question 18

-live in marine, freshwater, and damp terrestrial habitats
-undergo triploblastic development, they are acoelomates
-dorsoventrally flattened shape maximizes surface area for gas exchange
-divided into two lineages: catenulida, rhabditophora

Answer 18

flatworms

Question 19

-best-known rhabditophorans
- live in fresh water and prey on smaller animals
-have light-sensitive eyespots and centralized nerve nets - Their nervous system is more complex and centralized
than the nerve nets of cnidarians
-are hermaphrodites and can reproduce sexually, or
asexually through fission

Answer 19

planarians (free-living flatworm)

Question 19

or “chain worms,” reproduce asexually by
budding

Answer 19

catenulida

Question 20

more diverse and include both free-
living and parasitic species

Answer 20

rhabditophora

Question 21

-parasitize a wide range of hosts, and most have complex life cycles with alternating sexual and asexual stages
- hat parasitize humans spend part of their lives in snail hosts
-They produce surface proteins that mimic their host and release molecules that manipulate the host’s immune system

Answer 21

trematodes (parasitic flatworm)

Question 22

-are parasites of vertebrates and lack a
digestive system
-absorb nutrients from the host’s intestine - The scolex contains suckers and hooks for attaching to the host
- Proglottids are units that contain sex organs and form a
ribbon behind the scolex
- Fertilized eggs, produced by sexual reproduction, leave
the host’s body in feces

Answer 22

tapeworms (parasitic flatworm)

Question 23

-are tiny animals that inhabit fresh water, the ocean, and damp soil
-are smaller than many protists but are truly multicellular and have specialized organ systems
-have an alimentary canal
-can reproduce by parthenogenesis

Answer 23

rotifers

Question 24

a digestive tube with a separate mouth and anus that lies within a fluid-filled pseudocoelom

Answer 24

alimentary canal

Question 25

where females produce offspring from unfertilized eggs.

Answer 25

parthenogenesis

Question 25

-have a lophophore, a crown of ciliated tentacles around their mouth -have a true coelom -include two phyla: Ectoprocta and Brachiopoda

Answer 25

lophophorates

Question 26

- (also called bryozoans) are sessile colonial animals that can superficially resemble plants or corals -A hard exoskeleton encases the colony, and some species are reef builders

Answer 26

ectoprocts

Question 26

-superficially resemble clams and other hinge-shelled molluscs, but the two halves of the shell are dorsal and ventral rather than lateral as in clams -are marine and most attach to the seafloor by a stalk

Answer 26

brachiopods

Question 27

-includes snails and slugs, oysters and clams, and octopuses and squids -are marine, though some inhabit fresh water and some snails and slugs are terrestrial -are soft-bodied animals, but most are protected by a hard shell

Answer 27

molluscs

Question 28

Many molluscs also have a water-filled _____ ____ and feed using a rasplike ______

Answer 28

mantle cavity, radula

Question 29

-oval-shaped marine animals encased in an armor of eight dorsal plates -They use their foot like a suction cup to grip rock, and their radula to scrape algae off the rock surface

Answer 29

chitons

Question 30

-are aquatic and include many species of clams, oysters, mussels, and scallops -They have a shell divided into two halves drawn together by adductor muscles -Some bivalves have eyes and sensory tentacles along the edge of their mantle -The mantle cavity contains gills that are used for feeding as well as gas exchange

Answer 30

bivalves

Question 30

-About three-quarters of all living species of molluscs -are marine, but many are freshwater and terrestrial species -move slowly by a rippling motion of the foot or by cilia -Most have a single, spiraled shell that functions in protection from injury, dehydration, and predation -Most are herbivores, but some species use modified radula to feed on prey

Answer 30

gastropods

Question 31

- are carnivores with beak-like jaws surrounded by tentacles of their modified foot -They are able to immobilize prey with a poison present in their saliva -have a closed circulatory system, well- developed sense organs, and a complex brain

Answer 31

cephalopods

Question 32

shelled cephalods

Answer 32

ammonites

Question 33

-are coelomates with bodies composed of a series of fused rings -divided into two major clades; errantia, sedantaria

Answer 33

annelids

Question 34

-mobile, marine organisms -have a pair of paddle-like or ridge- like structures called parapodia (“beside feet”) on each body segment -Each parapodium has numerous chaetae, bristles made of chitin -Parapodia are not unique to this clade

Answer 34

errantians

Question 35

-tend to be less mobile than errantians -Some species burrow into the substrate, while others live in protective tubes -Tube-dwelling ___ often have elaborate gills or tentacles used for filter feeding -This clade also contains the leeches and the earthworms

Answer 35

sedentarians

Question 36

-live in fresh water; some are marine or terrestrial -include predators of invertebrates, and parasites that suck blood -secrete a chemical called hirudin to prevent blood from coagulating

Answer 36

leeches

Question 37

-eat through soil, extracting nutrients as the soil moves through the alimentary canal -are hermaphrodites but cross-fertilize -Some reproduce asexually by fragmentation

Answer 37

earthworms

Question 38

-are found in nearly all habitats of the biosphere. -most successful animal phylum. -body plan consists of a segmented body, hard exoskeleton, and jointed appendages

Answer 38

arthropods

Question 38

ecdysozoan are covered by a tough coat called a

Answer 38

cuticle

Question 38

-roundworms, are found in most aquatic habitats, in the soil, in moist tissues of plants, and in body fluids and tissues of animals -They have an alimentary canal, but lack a circulatory system -Body wall muscles are all longitudinal, and their contraction produces a thrashing motion

Answer 38

nematodes

Question 39

(sea spiders, horseshoe crabs, scorpions, ticks, mites, and spiders)

Answer 39

chelicerates

Question 39

(centipedes and millipedes)

Answer 39

myriapods

Question 39

Arthropods have an _______ in which hemolymph is circulated into the spaces surrounding the tissues and organs (hemocoel)

Answer 39

open circulatory system

Question 40

(lobsters and other crustaceans, as well as insects and their relatives)

Answer 40

pancrustaceans

Question 41

-named for clawlike feeding appendages called chelicerae -have an anterior cephalothorax and a posterior abdomen -have six pairs of appendages: the chelicerae (fangs), the pedipalps (various roles, including reproduction), and four pairs of walking legs -Most modern are arachnids, which include spiders, scorpions, ticks, and mites

Answer 41

chelicerates

Question 42

gas exchange in spiders occurs in respiratory organs called

Answer 42

book lungs

Question 43

-includes millipedes and centipedes -terrestrial -They have a pair of antennae and three pairs of appendages modified as mouthparts

Answer 43

myriapods

Question 44

-eat decaying leaves and plant matter -have many legs, with two pairs per trunk segment

Answer 44

millipedes

Question 45

-terrestrial insects are more closely related to crustaceans than myriapods -are more closely related to insects than other crustaceans (hence they are paraphyletic) -insects and crustaceans form this clade

Answer 45

pancrustaceans

Question 45

-are carnivores -have one pair of legs per trunk segment -Poison claws on the foremost trunk segment paralyze prey and aid in defense

Answer 45

centipedes

Question 46

-live in marine and freshwater environments; Include crabs, lobsters, shrimp, barnacles, etc. -have highly specialized appendages (up to 19 pairs!) -Small crustaceans exchange gases through the cuticle; larger crustaceans have gills have separate males and females -Isopods and amhipods include terrestrial, freshwater, and marine species

Answer 46

crustaceans

Question 47

-diversified several times following the evolution of flight, adaptation to feeding on gymnosperms, and the expansion of angiosperms (359-251 mya) -declined during the Cretaceous extinction, but has been increasing in the 65 million years since -undergo metamorphosis during their development

Answer 47

insects

Question 48

the young, called nymphs, resemble adults but are smaller and go through a series of molts until they reach full size

Answer 48

incomplete metamorphosis

Question 49

-are a group of armless species in the clade Asteroidea; only three species are known -live on submerged wood and absorb nutrients through a membrane that surrounds their body

Answer 49

asteroidea: sea daisies

Question 49

have larval stages known by such names as maggot, grub, or caterpillar

Answer 49

complete metamorphosis

Question 50

-share developmental characteristics -Radial cleavage -Formation of the anus from the blastopore -defined primarily by DNA similarities

Answer 50

deuterostomes

Question 51

- slow-moving or sessile marine animals -A thin epidermis covers an endoskeleton of hard calcareous plates -Males and females are usually separate, and sexual reproduction is external -have a unique water vascular system, a network of hydraulic canals branching into tube feet that function in locomotion and feeding, pentaradial symmetry -adults have radial symmetry w pentaradial; larvae have bilateral symmetry

Answer 51

echinoderms

Question 52

-have multiple arms radiating from a central disk -feed on bivalves by prying them open with their tube feet, everting their stomach, and digesting their prey externally with digestive enzymes -can regrow lost arms

Answer 52

asteroidea: sea stars

Question 52

Echinoderms have a unique ________, a network of hydraulic canals branching into _______ that function in locomotion and feeding, pentaradial symmetry

Answer 52

water vascular system, tube feet

Question 53

-have a distinct central disk and long, flexible arms, which they use for movement -Some species are suspension feeders, while others are predators or scavengers

Answer 53

ophiuroidea: brittle stars

Question 54

-consists of two basal groups of invertebrates as well as vertebrates -are bilaterally symmetrical coelomates with segmented bodies -did not evolve from echinoderms, but evolved separately from them for at least 500 million years

Answer 54

chordates

Question 54

-live attached to the substrate by a stalk -Feather stars can crawl using long, flexible arms -Both are suspension feeders -Crinoidea have changed little over the course of evolution

Answer 54

crinoidea: sea lilies and feather stars

Question 55

-have no arms but have five rows of tube feet -Their spines are used for locomotion and protection -feed on seaweed using a jaw-like structure on their underside

Answer 55

echinoidea: sea urchins and sand dollars

Question 56

-lack spines, have a very reduced endoskeleton, and do not look much like other echinoderms - have five rows of tube feet; some of these are developed as feeding tentacles

Answer 56

holothuroidea: sea cucumbers