Ch. 28 and 29

what percent of all animals are invertebrates

95%

studies of ____ have shown that pandas are more closely related to bears than to raccoons

DNA

segmentation is a trait of earthworms, not vertebrates (t/f)

F

segments are totally independent of one another (t/f)

F

sponge cells are organized into tissue (t/f)

F

sponges are classified as animals because they're mobile (t/f)

F

____ live in fresh water and attach to rocks by means of sticky secretion produced by an area called the _____

Hydras, basal disk

amoebocytes carry nutrients and remove wastes (t/f)

T

evidence of segmentation in human beings can be seen in the backbone (t/f)

T

segmentation offers evolutionary flexibility because a small change in an existing segment can produce a new type of segment with a different function (t/f)

T

segmented animals are constructed from a series of repeating, similar units called segments (t/f)

T

polyp

a basic kind of cnidarian: tubelike and usually attached to a rock or some other object

medusa

a basic kind of cnidarians: free floating, jelly-like and often umbrella shaped

gastrovascular cavity

a digestive tract with only one opening --> allows for specialization

coelom

a fluid-filled body cavity found between the body wall and the digestive tract (gut)

digestive tract

a gut with two openings that moves food from the mouth to the anus

spongin

a resilient, flexible protein fiber which makes up the "skeletons" of sponges

exoskeleton

a rigid external skeleton (outside the body) that encases the body of an animal

body plan

a term used to describe an animal's shape, symmetry, and internal organization

body cavities:

acoelomates: no body cavity pseudocoelomates: "false" body cavity coelomates: true cavity * evolutionary advancement going down

what is the benefit of not having cell walls

allows mobility that other multicellular organisms don't have

clues to animal relations can be found by comparing the ____ and physiology of living animals

anatomy

parthenogenesis is an ex. of ___ rep.

asexual

Reproduction

asexual--> clones *budding *regeneration *parthenogenesis sexual rep.--> variation *fertilization (internal v. external) *eggs (ovaries) *sperm (testes) *hermaphrodites

sea anemones reproduce ____ by slowly pulling themselves apart into two halves

asexually

sponges can produce

asexually and sexually

symmetry:

asymmetry: irregular shape (SPONGE) radial: body arranged around central axis (SEA ANEMONE) bilateral: distinct right and left halves (HUMANS)

why don't flatworms need a respiratory or circulatory system?

b/c oxygen and carbon dioxide diffuse in and out of the body, and portions of the flatworm's highly branched GVC run close to all the tissues, giving cells access to food

posterior

back (tail end)

spongin used for

bath sponge

in all animals except sponges, the zygote undergoes cell divisions forming a hollow ball of cells called a(n)

blastula

closed circulatory system

blood enriched with O2 and nutrients

open circulatory system

blood supplies tissues with nutrients and oxygen

pseudocoelomates

body cavity is between mesoderm and endoderm

bilateral symmetry

body has a distinct right and left half

asymmetrical

body is irregularly shaped

radial symmetry

body parts arranged around a central axis (can be divided evenly in several places)

ventral

bottom (stomach side)

ganglia

brain-like structure (cluster of neurons which process more info)

obelia live in colonies that form when one polyp reproduces by _____

budding

marine sponges reproduce asexually by _____ and ______

budding and fragmentation

each tiny coral polyp secretes a tough, stone like outer skeleton of _______

calcium carbonate

amoebocytes

cells that move around the mesoglea

bilateral symmetry:

cephalization: gathering of sensory structures in head (AKA brain) dorsal: top (backside) ventral: bottom (stomach side) anterior: front (head region) posterior: back (tail end) lateral: right or left sides

Planarians are members of the _____ Turbellaria, and they are ______

class, free-living

what do collar cells do and how do their flagella help?

collar cells move water through canals (internal) in sponges and flagella rotate to create a current to move the water

____ cells move the sperm cells into the ____ where fertilization occurs

collar, mesoglea

endoskeleton

composed of a hard material such as bone inside an animal

hydrostatic skeleton

consists of water that is contained under pressure in a closed container

three types of sponges

demosponges, silicious, calcareous

Main tissue and organ functions

digestion respiration circulation (open v. closer) nerve impulses (nerve net, ganglia, brain) support (hydrostatic, exoskeleton, endoskeleton) excretion (gets rid of waste)

the layer of cells in the blastula that gives rise to the outer layer of skin, the nervous system and the sense organs

ectoderm

blastulas develop into three distinct cell layers:

ectoderm, endoderm, mesoderm

life cycle of Ascaris

eggs are carried from human waste to soil and when ingested, enter intestine and develop into larvae, which bore through blood vessels in intestine and enter blood stream

clues to animal relations can be found by comparing patterns of development in animal

embryos

digestive system

enables digestion of foods that are larger than individual cells

the layer of cells in the blastula that gives rise to the lining of the digestive tract, respiratory system and many glands

endoderm

digestion in cnidarians begins outside the cell, or _____, and is completed inside the cell, or _______ (in the gastrovascular cavity)

extracellularly, intracellularly

gills

extremely thin projections of tissue rich in blood vessels providing a large surface for gas exchange --> WORKS IN WATER

how do sponges get nutrients?

filter water--> get food molecules from that

choanocytes

flagellated cells that move water through a sponge to trap plankton

tentacles

flexible, fingerlike extensions of cnidarians--> capture and subdue prey

clues to animal relations can be found by looking at the ____ record

fossil

a sponge can rep. by ____ its body

fragmenting

anterior

front (head region)

mesoglea

gel-like substance in which specialized cells are embedded

when living conditions become harsh, some freshwater sponges form _____, clusters of amoebocytes encased in protective coats

gemmules

coelomates

have a true coelom

acoelomates

have no body cavity

calcareous sponges

have spicules composed of calcium carbonate

glass sponges

have spicules made of silica

species of animals that have both testes and ovaries are called

hermaphrodites

three classes of cnidarian

hydrozoa, scyphozoa and anthozoa

animals that live on land usually reproduce by ____ fertilization

internal

oscula

large openings in a sponge's body wall through which water exits

cnidarians: movement

looping or cartwheeling

the layer of cells in the blastula that gives rise to most of the skeletons, muscles and circulatory system

mesoderm

the egg cells reside in the

mesoglea

marine hydrozoans are ___ complex than fresh-water hydrozoans and ____ numerous than are fresh-water hydrozoans

more, more

animals basic characteristics

multicellular eukaryotes no cell wall heterotrophs mobility diploidy sexual rep. with sperm and egg blastula formation (except sponges) tissues (except sponges)

function of spicules

needle like structures that provide support (act like skeleton-- mesh like internal skeleton) and ward of predators (prickly defense-- protection)

a small barbed harpoon within each cnidocyte

nematocyst

neurons

nerve cells (specialized for carrying messages in form of electric impulses

what does the epidermis do?

offers protection

hydra: body openings?

one

endoparasites

parasites inside host

ectoparasites

parasites outside host

sessile

permanently attached to a submerged surface

what does sessile mean?

permanently attached to a submerged surface

a(n) _____ tree shows how animals are related through evolution

phylogenetic

the members of the _______ Platyhelminthes, commonly known as flatworms, exhibit ______ symmetry

phylum, bilateral

some anthozoans reproduce by budding, but others release eggs and sperm into the ocean where the fertilized eggs become _____

planulae (and later develop into polyps)

the sperm and egg of Obelia medusae fuse and produce free-swimming ______ that eventually settle on the ocean bottom and grow into new _____

planulae, polyps

the largest class of cnidarians is the class anthozoa, which exist only as ____

polyps

sperm cells from one sponge enter another sponge through its

pores

another name for sponges

porifera ("pore bearing")

how are gemmules used to reproduce asexually

produced in late fall and the tissue surrounding is dissolves new sponge grows out of genital

tapeworms consist of a head with suckers and a few hooklike structures followed by a string of body sections called

proglottids

what benefit do animals derive from having a coelom?

protects from movement of muscles around; animals can move around without damaging internal organs or interfering with function

cnidarians have what kind of symmetry

radial symmetry

most coral polyps live in colonies called

reefs

excretory system

removes wastes produced by cellular metabolism

lungs

respiratory organs which allow for gas exchange with the environment --> IN AIR

lateral

right or left sides

cephalization

sensory structures and nerves concentrated at the body's anterior

why is pseudocoelom of roundworms an important evolutionary milestone

serves as circulatory and simple gas exchange system

spicules

skeletons made of tiny needles of silica or calcium carbonate that some sponges have

demosponges

sponges that contain spongin (sometimes reinforced with spicules made of silica) third class of sponges

digestion in hydra

starts extracellularly and ends intracellularly

cnidocytes

stinging cells located on tentacles--> subdue prey

respiratory system

takes in oxygen and releases carbon dioxide

flukes hace a thick protective covering of cells called the _____ that helps them avoid being digested by their hosts

tegument

digestion

the breakdown of food in order to get energy and nutrients

excretion

the removal of wastes produced by cellular metabolism

what is the difference between the life cycle of true jellyfish and that of Obelia?

the true jellyfish go through an inconspicuous polyp stage at some point in their life cycle

why are members of the phylum Ctenophora not considered true jellyfish?

they only have a medusa stage and they have no cnidocytes

how do sponges get rid of wastes?

through ameobocytes, which are sponge cells that carry away waste

ostia

tiny openings in a sponge's body wall through which water enters

the cells in cnidarians are arranged into ____, which are specialized cells that work together

tissues

the cells of all animals except sponges are organized into structural and functional units called

tissues

what do all animals have that sponges don't

tissues and blastula formation

why do sponges have skeletons?

to prevent the sponge from collapsing in on itself (support and protection)

dorsal

top (backside)

circulatory system

transports oxygen and nutrients

hydras can sometimes move by _____

tumbling

how many layers of cells are there in marine sponges

two

how do hydra get food?

use stingers to grab and immobilize food before stretching their mouths wide to cover and digest food

heterotrophy

when animals can't make their own food most move from place to find/eat food

sexual rep.

when organisms produce gametes which come into contact with each other to form a newborn organism --> genetic variation

hydra: supporting framework?

yes: mesoglea (gell-like layer between epidermis and gastrodermis)