Exam 3

CH24-26, 31

Invertebrates

Invertebrates

no backbone, most diverse and numerous of land and ocean animals

animals

multicelled heterotrophs with unwalled cells, develop from embryo to adult forms, all move during part or all of their lifetime

all animals are ( ) and constitute the clade ( ) also called ( )

multicellular, Metazoa, Animalia

clusters

the earliest animals were aggregations of cells

jellies and cnidarians have ( ) tissue layers

two

outer ectoderm and inner endoderm

no internal organs

mesoderm

middle layer; internal organs develop from the mesoderm

assymetrical

their body cannot be divided into two halves that are mirror images

radial symmetry

body parts are arranged around a central axis; like spokes on a wheel

bilateral symmetry

the body’s left and right halves are mirror images

cephalization

evolutionary process in which cells and sensory structures become concentrated at the front of the body. Helps animals find food or avoid threats as it moves head first through the environment

the two lineages of bilateral animals are

protosomes and deuterostomes

protostomes

the first opening that appears in an embryo becomes the mouth. most invertebrate lineages

deuterostomes

the second opening on the embryo’s surface develops into a mouth; the first opening is the anus. invertebrate lineage of echinoderms and all vertebrates

sponge digestion

in sponges digestion is intracellular

gastrovascular cavity

how cnidarians and flatworms digest; saclike cavity that functions in digestion and gas exchange

pseudocoelom

roundworm digestion cavity; partially lines with tissue from mesoderm

complete digestive tract

most bilateral animals have this; tubular gut with openings at either end has a coelom

coelom

a body cavity fully lines with tissue derived from mesoderm (mesentery)

colonial theory of animal origins

states that animals evolved from a colonial opisthokont protist

choanoflagellate

the modern protist most closely related to animals

earliest evidence of animals

biomarker characteristic of sponges found in 635 million years old sedimentary rock

oldest evidence of animals dates to the ( ) 635-541 MYA

Edicaran

Dramatic adaptive radiation

occured during the Cambrian (542-488 MYA); supercontinent Gondwana underwent ta dramatic rotation. movement of the landmass would have caused allopatric speciation worldwide

all animal lineages present by the end of the period

?

sponges have no

tissues or organs

sessile

live attached to a surface

suspension feeders

filter food from the surrounding water

collar cells

make up sponges; different specialized cells that line the inner surface

hermaphrodites

each individual can produce both eggs and sperm

larva

sexually immature form that differs from the adult in its body plan

body plans of cnidarians

radially symmetrical and have two tissue layers. no internal organs

medusa

bell/dome shaped cnidarian body fringed by tentacles

polyp

pillarlike cnidarian body topped with tentacles

cnidocytes

specialized cells. stinging cell unique to cnidarians. sting the prey, tentacles push the prey through the mouth

nerve net

mesh of nerve cells with no central control organ

Hydrozoan

cnidarian class. ex: Hydra, a freshwater predatory polyp

anthozoans

cnidarian class, corals and sea anemones; coral reefs consist of colones of polyps that enclose themselves in a framework of secreted calcium carbonate

cubozoans

cnidarian class; box jellies, active swimmers with structurally complex eyes complete with a lens

scyphozoans

cnidarian class, jellies that wash up on beaches, Portuguese man-of-war

pharynx

tube connecting the mouth to the digestive track. a muscle in flatworms

ganglia/ganglion

cluster of nerve cell bodies. simple brain in flatworms

nerve cords

bundle of nerve fibers that runs the length of the body in many invertebrates. found in flatworms

penis fencing

some marine flatworms will battle over who will assume the male role in this behavior

closed circulatory system

system in which blood flows to and from a heart or hearts through a continuous series of vessels. found in bilateral annelid worms.

polychaetes and oligochaetes have ( ) bristles on their segments

chitin-reinforced

clitellum

during mating this secretory organ produces a mucus that glues two worms together as they swap sperm. found in earthworms

mantle

skirt-like extension of the upper body. found in mollusks

all mollusks have..

a complete digestive tract and reduced coelom

radula

tongue like organ hardened with chitin. found in mollusks, chitons

open circulatory system

circulatory system in which fluid leaves vessels and mingles with tissue fluid before returning to the heart. found in mollusks.

molting

shedding and replacement of an animal body part. found in roundworms

arthropod sex

sexes are usually separate but there are some hermaphrodites

arthropod

invertebrate with jointed legs and a hard exoskeleton that is periodically molted; insect and crustaceans

compound eye

of some arthropods; an eye that consists of many individual units, each with a lens, excels at detecting movement

antenna

of some arthropods, sensory structure on the head that detects touch and odors

exoskeleton

hard external parts that muscles attach to and move

earliest known fossil of a land animal

myriapod 428 MYA

chelicerata

subphylum of arthropod; two main body segments: a cephalothorax (fused head and thorax) and an abdomen. paired with specialized feeding appendages (chelicerae) that give it its name.

arachnids

arthropod class. almost all terrestrial: spiders, scorpions, ticks, mites

myriapoda

subphylum of arthropod. elongated bodies composed of several segments; usually nocturnal ground dwellers and predators

crustacea

subphylum of arthropod. “insects of the sea” two main body segments: cephalothorax and abdomen

echinoderms

the largest group of invertebrate deuterostomes

chordates

group of biaterally symmetrical, coelomate animals. have a complete digestive system and a closed circulatory system

traits unique to chordate embryos

notochord, hollow nerve cord runs parallel to notochord, gill slits, muscular tail

notochord

stiff, flexible connective tissue; stiff rod of connective tissue that runs the length of the body in chordate larvae or embryos

Lancelets

invertebrate chordate. subphylum cephalochordata

tunicates

invertebrate chordate. subphylum urochordata; studies of genes and development have identified these as most closely related to vertebrates

endoskeleton

internal skeleton

first vertebrates

jawless fish that sucked up food

tetrapods

four legged walkers; vertebrate that has four bony limbs or is a descendant of a four-limbed ancestor

amniotes

vertebrate with eggs that enclose the embryo within a waterproof membrane; most diverse land vertebrates. branched off from an amphibian ancestor during the Carboniferous

fishes

first vertebrate lineage to evolve

Cyclostomata

fish clade meaning round mouthed. includes Lampreys and Hagfishes

cloaca

an opening that serves as the exit for digestive and urinary waste, and also functions in reproduction. a multipurpose opening

Lampreys

don’t feed as adults, some are parasites of fish.

scales

hard, flattened structures that cover the skin

placoderms

early jawed fish. means “tablet skin” from their bony armor. lived during Devonian period, some were very large and inhabitated what is now Ohio

acanthodians

spiny fins. early fish species. went extinct at the end of the Permian. arose during same time as placoderms

cartilaginous fishes

Chondrichthyes; jawed fish with a skeleton that consists of mainly or entirely of cartilage. most are sharks and rays. cloaca functions in reproduction and to remove wastes.

ray finned fishes

Actinopterygii; bony fish that has fin supports derived from skin

lobe-finned fishes

Sarcopterygii; bony fish that has thick fleshy fins supported by bones. sexes are separate and fixed

ray-finned fishes

have thin, membranous fins, swim bladder

swim bladder

gas-filled (sac) that can be adjusted to regulate buoyancy. found in ray finned fish

teleost

lineage of ray-finned fish. includes 99% of ray-finned fishes (about half of all vertebrates)

marine coelacanths

lineage of lobe-finned fishes. thought to be extinct until 1938 when a living one of this was found in the Indian Ocean, now know of several modern species

freshwater lungfishes

lineage of lobe-finned fish. have lungs, oxygen diffuses from the lungs into the blood

amphibians

scaleless, land-dwelling vertebrates. first tetrapods

dinosaurs and birds

birds branches off from a dinosaur lineage during the Jurassic

endotherms

maintain body temperature by adjusting metabolic heat production

ectotherms

body temperature varies with the environment

squamata

reptiles; lizards and snakes. Most diverse group of modern reptiles

turtles

Testudines. toothless, bony, keratin-covered shell attached to skeleton

crocodilians

crocodiles, alligators, and caimans. closest living relatives to birds

feathers

filamentous keratin structures that derived from scales

bird reproduction

fertilization occurs through the cloaca

monotremes

mammal. least diverse group of mammals, egg laying, oldest surviving mammal lineage, don’t have nipples but produce milk. include echidnas and the platypus

marsupials

pouched mammals. young briefly develop in mother’s body, finish development inside mother’s pouch. have a cloaca, mostly in australia.

placental mammals

develop for an extended period inside the mother’s body where they are nourished by means of a placenta

placenta

organ that forms during pregnanacy and allows diffusion of substances between the maternal and embryonic bloodstreams