Bio 2110 Exam 2 All set

What are the characteristics of animals?

Multicellular heterotrophic eukaryotes that ingest food, lack cell walls, and are held together by collagen; most have nervous and muscle tissues.

Animals obtain nutrition through .

ingestion

Animals lack in their cells.

cell walls

What protein primarily holds animal cells together?

collagen

Most animals possess what two specialized tissues?

nervous tissue and muscle tissue

Define ploidy.

The number of sets of chromosomes in a cell.

Diploid cells have sets of chromosomes.

two

Haploid cells have set of chromosomes.

one

What is cleavage?

Mitotic cell division without cell growth.

What is a blastula?

A hollow ball of cells with a blastocoel.

What is gastrulation?

Rearrangement of the embryo forming germ layers.

The three germ layers are , , and .

ectoderm, mesoderm, endoderm

Ectoderm gives rise to .

outer covering and nervous tissue

Endoderm gives rise to .

digestive tract lining and organs

Mesoderm gives rise to .

muscles and most organs

Some animals have a sexually immature stage called a .

larva

Larvae undergo _______ to become juveniles.

metamorphosis

What are Hox genes?

Regulatory genes with homeobox sequences that control body patterning.

The oldest accepted animal fossils are from the ______ biota.

Ediacaran

The Cambrian Explosion occurred during the ____ Era.

Paleozoic

One hypothesis for the Cambrian Explosion is new ______ relationships.

predator-prey

Rise in atmospheric ________ may have fueled Cambrian diversification

Oxygen

Evolution of the ______ gene complex increased developmental flexibility.

Hox

Asymmetry means .

no symmetry

Radial symmetry means .

any slice through central axis produces mirror images

Bilateral symmetry means .

only one plane produces mirror images

Most animals have ______symmetry.

bilateral

Sponges lack_____ tissues.

true

Diploblastic animals have _____ germ layers.

two

Triploblastic animals have _____ germ layers.

three

Body cavities occur only in _____ animals.

triploblastic

A true coelom is completely lined ______with .

mesoderm

A pseudocoelom is partially lined with _____.

mesoderm

Acoelomates have .

no body cavity

Why have a body cavity?

To cushion organs, act as a hydrostatic skeleton, and allow organ movement.

Protostomes have _____ cleavage.

spiral and determinate

Deuterostomes have ______ cleavage.

radial and indeterminate

In protostomes, the blastopore becomes the _____.

mouth

In deuterostomes, the blastopore becomes the _____

anus

Sponges belong to phyla _____and ____.

Calcarea, Silicea

Sponges are ____feeders.

suspension

Water enters a sponge through _____and exits through the _____.

pores, osculum

Choanocytes create ____for feeding.

water currents

Choanocytes resemble _____.

choanoflagellates

Sponges reproduce sexually and asexually by _____.

budding

Most sponges are _______.

hermaphrodites

Cnidarians include ______.

jellyfish, corals, hydras

Cnidarians have _____symmetry.

radial

Cnidarians are ____blastic.

diploblastic

The cnidarian digestive compartment is the _____.

gastrovascular cavity

The gastrovascular cavity has _____ opening(s).

one

Two cnidarian body forms are____ and ____.

polyp, medusa

Polyps have their mouth facing .

upward

Medusae have their mouth facing .

downward

Cnidocytes contain ______that inject toxins.

nematocysts

Corals exist only as .

polyps

Corals secrete _____ skeletons.

calcium carbonate

Coral reefs create _____for many species.

habitat

Ctenophores have eight rows of fused ______.

cilia (“combs”)

Cnidarians are predators that use _____ to capture prey.

tentacles with cnidocytes

Sponges have _____ but no true tissues.

cell layers

The mesohyl in sponges is a

jelly-like layer between cell layers

Amoebocytes in sponges function in

digestion, structure, and reproduction

Cnidarians belong to clade

Eumetazoa

Sponges are considered _____ animals.

basal

The medusa stage is typically ____.

motile

The polyp stage is typically ____.

sessile

Cnidarians have simple ____ nets.

nerve

Cnidarians lack _____ systems.

circulatory and respiratory

Corals rely on symbiotic ____ .

dinoflagellates

Cnidarian larvae are called _____ .

planulae

Cnidocytes discharge when the _____ is triggered.

cnidocil (“trigger”)

Sponges have no ____ or _____.

nerves, muscles

The spongocoel is the ____ .

central cavity of a sponge

Cnidarians are among the oldest lineages of ____ .

Eumetazoans

Lophotrochozoans are characterized by having either a ____or a ____ .

lophophore, trochophore larva

Lophotrochozoans are _____blastic and have_____ symmetry.

triploblastic, bilateral

Lophotrochozoans are (protostomes or deuterostomes?).

protostomes

Flatworms belong to phylum _____ .

Platyhelminthes

Flatworms have _____symmetry.

bilateral

Flatworms are (type of body cavity).

acoelomate

Flatworms have an incomplete digestive system called a .____

gastrovascular cavity

Flatworms lack organs for .

circulation

Flatworms rely on____ for gas exchange.

diffusion

Flatworms show ______, meaning concentration of sensory structures at the head.

cephalization

The pharynx of a flatworm is used for ____.

feeding and ingestion

Class Turbellaria includes .

free-living flatworms (planarians)

Parasitic flatworms include classes___,____ and ____.

Monogenea, Trematoda, Cestoda

Monogeneans and trematodes are ____ .

parasitic

Trematodes often require ____hosts.

multiple

The first larval stage of trematodes is the .

miracidium

The second larval stage of trematodes is the .

cercaria

Parasites have high ___ effort.

reproductive

Reproductive effort is defined as .

the amount of body dedicated to reproduction

Tapeworms belong to class .

Cestoda

Tapeworms lack a ______system.

digestive

The head of a tapeworm is called the .

scolex

Tapeworm body segments are called .

proglottids

Tapeworms absorb nutrients that are already .

predigested by the host

Tapeworms can reach lengths of over .

20 meters