Bio 107 Exam 4 Oliver Ljustina

Animals are eukaryotic, multicellular, heterotrophic organisms belonging to this kingdom

Animalia

The first animals evolved around

570 mya (Ediacaran Period)

Majority of animal phyla evolved during this period

Cambrian Period

First animals (arthropods) moved onto land during this period

Silurian Period

First vertebrates moved onto land during this period

Devonian Period

Animals are the closest relatives of animals are thought to be ___________________, which colonial, heterotrophic protists

choanoflagellates

Animals share several characteristics

-Multicellular

-Lack cell walls

-Heterotrophs

-Development involves a blastula stage

-Animal cells secrete an extracellular matrix

Upon formation of a zygote rapid cell division forms a ball of cells called

morula

Morula hollows out to form a

blastula

Convergent in other groups, animals in particular have a _______________________ in their extracellular matrix

basement membrane

(sponges) have specialized cells, but these do not interact to form tissues

parazoans

All animals that are not parazoans belong to the ___________________, which have distinct tissues that perform specific functions

eumetazoan

Four basic tissue types found in animals are:

connective, muscle, nervous, and epithelial

contains protein filaments that slide past one another allowing for movement

Muscle tissue

allow animals to respond to stimuli and maintain homeostasis

Nervous tissues

line outer and inner surfaces of organs and other tissue types and allow for absorption, secretion, protection, and other functions

Epithelial tissues

Cell layers are formed when the blastula folds in on itself, forming the

gastrula

The gastrula may be composed of two, or three tissue layers called

primary germ layers

The three layers are:

endoderm, ectoderm, mesoderm

forms the inner-most layer of the gastrula

endoderm

are primarily formed from the endoderm

Epithelial tissues

forms between the endoderm and the ectoderm in the gastrula

mesoderm

Many ________________ are formed from the mesoderm

connective tissues

the outermost layer of the gastrula

ectoderm

Forms nervous tissue, as well as the outer ________________ (skin)

epithelial tissues

have two germ layers (lack mesoderm)

Radiata

have all three germ layers

Bilateria

Radiata include most animals with ___________________

radial symmetry

The majority of animals belong to the _____________, which are characterized by bilateral symmetry

bilatera

Bilaterally symmetrical animals exhibit ____________, meaning sensory structures are concentrated in the head

cephalization

the first opening of the tube forms the mouth

protostomes

the first opening of the tube forms the anus

deuterostomes

There are three informal groups based on body cavity arrangement:

coelomates, pseudocoelomates, and acoelomates

have a body cavity called a coelom with a complete mesoderm lining

Coelomates

have an incomplete mesoderm lining, which does not allow for arrangement of organs in cavity with same complexity

Pseudocoelomates

lack any cavity at all, having semi solid mesodermal tissues between the gut and the body wall

Acoelomates

The eumetazoans have a range of digestive tracts, broadly broken into

complete and incomplete digestive tracts

In an ______________________________, there is a single opening by through which food is taken, and waste expelled

incomplete digestive tract

Digestion occurs in the

gastrovascular cavity

In a ________________________, food passes in one direction; from the mouth, to the anus

complete digestive tract

involves distinct lifestyle phases, where a larva undergoes metamorphosis to adulthood

Indirect development

does not involve metamorphosis

Direct development

Sponges belong to the phylum porifera

containing around 5,000 species

The simplest animals, they are included in the group _______________, as they lack distinct tissues like other animals

parazoa

earliest fossil sponges date back to ____________ (Ediacaran Period)

600 mya

Body is hollow and is held in shape by the _______________, substance made mainly of collagen

mesohyl

have flagella that move water through sponge, and are primary site of nutrient absorption

Choanocytes

are structural elements that help deter predators

Spicules

Asexual reproduction occurs by

budding

Many sponges are hermaphroditic, with sperm being produced by choanocytes, and eggs being produced by

archeocytes

Sponges are ____________, meaning they do not move

sessile

Sponges __________________ to filter plankton and organic particles from the water column

use their choanocytes

play a major role in sponge taxonomy, in terms of composition and shape

Spicules

is the largest class, 76.2 % of species

Desmospongiae

are referred to as the glass sponges and are characterized by their distinct, silica spicules

Hexactinellidiae

belong to the phylum Cnidaria

Sea anemones, coral, and jellyfish

Some of the oldest animal fossils are of cnidarians and go back to the

Ediacaran Period

have true tissues, derived from two germ layers, the endoderm and ectoderm and belong to the eumetazoa

Cnidarians

Cnidarians have _____________ (comprise the group radiata), and are __________________ compared to animal groups

-radial symmetry

-relatively simple

Two main cell layers sandwich a middle layer of jelly-like material called _______________, forming the main body of many cnidarians

mesoglea

The mesoglea contains

muscle bundles and nerve fibers

The lone opening serves as mouth and anus, and leads to

the gastrovascular cavity

Many cnidarians have ______________ which are used for feeding and defense

tentacles

Tentacles contain _______________ which contain tiny harpoons that sting prey and predators alike

cnidocytes

Cnidarians have two basic body plans:

medusae and polyps

are mobile forms in many groups and have tentacles dangling down

Medusae

are sessile, are often the reproductive stage in some cnidarians, and have their tentacles pointing upward

Polyps

There are four classes of cnidarians:

Anthozoa, Hydrozoa, Scyphozoa, and Cubozoa

are the most diverse group including more that 6,000 species

Anthozoans

Anthozoans are often sessile, colonial polyps that form elaborate ________________ structures

calcium carbonate

are composed of a single, sessile polyp, with a soft exterior

sea anemones

Coral grow in large, polyp colonies and____________________________________ shells

secrete elaborate calcium carbonate

Coral are known for their symbiotic relationships with _____________, which are photosynthetic dinoflagellates

zooxanthellae

coral in particular are responsible for building coral reefs

Hermatypic

are sessile, colonial polyps known as sea fans, that grow in broad, fan-like structures

Gorgonians

are individually small, potentially colonial, predatory cnidarians

Hydrozoans

is an order of hydrozoans comprised of colonial organisms

siphonophorae

Hydrozoan systematics are composed of individual animals called _______ that have specific functions

zooids

Large, predatory, individual organisms, _________________form the group known as the true jellyfish

Scyphozoans

are distinguished by their cube shaped medusae, which has a set of tentacles on the lower corners

Cubozoa

Some of the simplest bilaterians are the flatworms, which

belong to the phylum Platyhelminthes

Modern systematics has identified two classes of flatworms:

Rhabditophora, and Catenulida

The class ____________________ includes the vast majority of flatworms

Rhabditophora

rodlike structures that secrete mucus for defense and terrestrial locomotion

rhabdites

are a class of flatworms characterized by nonmobile sperm

Catenulids

Roundworms belong to the phylum

Nematoda

have a complete digestive tract enclosed by a pseudocoelom

Nematodes

The mouth often includes a hardened structure called a _____________, used in predation/parasitism

stylet

Found near the head are sensory structures called

amphids

Segmented worms belong to the phylum

Annelida

The oldest putative annelid fossil dates back to the

Cambrian Period

characterized by well defined segments and a well developed coelom

Annelids

Locomotion is performed by wave like contractions of segments aided by __________, which are hair-like projections along the body

setae

Major annelid groups are placed into one of two, major groups:

Clitellates, and Polychaetes

Clitellates are the class of annelid worms characterized by having a _____________, important in reproduction

clitellum

Called bristle worms, Polychaetes are characterized by ____________, fleshy vascularized protrusions used in locomotion and respiration

parapodia

The phylum ___________________ includes over 85,000 extant species, including organisms such as clams, oysters, snails, and octopuses

Mollusca

The generalized mollusk is characterized by a _________________________________, a protein hardened by calcium carbonate

shell that is composed of conchiolin

The shell sits atop the ____________, which secretes the conchiolin to form the shell

mantel

Some organ systems may lie within a fold in the mantel called the mantel cavity

mantel cavity