Bio 114 Exam 3

Describe what all animals have in common.

All animals are multicellular, eukaryotic organisms that consume other organisms for energy, lack cell walls, and are capable of movement at some stage of their life. They typically reproduce sexually and develop from a blastula during early embryonic stages

Describe what sets Kingdom Animalia apart from other kingdoms

its members are multicellular, heterotrophic, lack cell walls, are capable of movement, and develop from a blastula, unlike plants, fungi, and other kingdoms

Describe basic animal development from zygote to gastrula

begins with a zygote, which undergoes cleavage to form a morula, then a hollow blastula. the blastula folds during gastrulation to form germ layers (ectoderm, mesoderm, endoderm), setting up the body plan

Differentiate between protostomes and deuterostomes

they differ mainly in early development:

in protostomes, the blastopore becomes the mouth, cleavage is spiral and determinate (cells already have jobs), and the coelom forms by splitting

in deuterostomes, the blastopore becomes the anus, cleavage is radial and indeterminate (cells are flexible, can become full organism if separated), and the coelom forms by outpocketing (cells bulge out to make a new space inside the body.)

• Protostomes = mouth first, spiral/determinate cleavage

• Deuterostomes = anus first, radial/indeterminate cleavage

zygote

The single cell formed when sperm fertilizes an egg.

cleavage

Rapid cell divisions of the zygote without growth, producing smaller cells called blastomeres

blastomere

An individual cell produced by cleavage.

morula

A solid ball of blastomeres formed after several cleavages.

blastula

A hollow ball of cells with a fluid-filled cavity called the blastocoel.

blastucoel

The fluid-filled cavity inside the blastula

gastrula

The stage after the blastula folds inward (gastrulation) to form germ layers.

germ layers

The three primary layers formed during gastrulation:

Ectoderm → skin, nervous system

Mesoderm → muscles, bones, circulatory system

Endoderm → digestive tract, internal organs

gastrulation

The process where the blastula folds inward to form the germ layers.

archenteron

The primitive gut formed during gastrulation.

blastopore

The opening of the archenteron; becomes the mouth or anus depending on the organism

Describe diploblastic and triploblastic organisms

Diploblastic organisms have two germ layers (ectoderm and endoderm) and simple bodies

triploblastic organisms have three germ layers (ectoderm, mesoderm, and endoderm) allowing for complex organs and structures

Describe 3 basic germ layers and where they arise from in protostomes and deuterostomes

Ectoderm: Forms skin and nervous system, Arises from the outer layer of the embryo.

Mesoderm: Forms muscles, bones, circulatory system

• Protostomes: arises by splitting of the solid mesoderm

• Deuterostomes: arises by outpocketing from the gut

Endoderm: Forms gut and internal organs, Arises from the inner layer of the embryo (the archenteron).

coelomates

have a true coelom → a body cavity completely lined with mesoderm.

Allows space for organs to grow and move independently, facilitates more complex organ systems and provides cushioning and support for internal organs

ex: humans, earthworms

outer is the ectoderm, middle is the mesoderm and lines both body wall and gut, inner is the endoderm and the space is the coelom

Describe what tissue is and why it is important for animals

tissue is a group of similar cells that work together to perform a specific function. animals have different types of tissue that make their bodies organized and efficient

it is important because tissues allow cells to specialize, so not every cell has to do everything, and they make complex structure and organs possible and allow animals to move, sense their environment, digest food, and circulate blood efficiently

Know what a HOX gene is

it is a special gene that controls the body plan of an animal during development.

it tells cells where to grow things like the head, tail, arms, legs, or wings

it is important because it makes sure body parts form in the right place and changes in HOX genes can cause major differences in body structure between species

Recognize, interpret, and draw a phylogeny for the animal phyla I have asked you to know

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Describe animal body plans in terms of symmetry

asymmetry: no specific shape or symmetry, usually don’t move much and simple in structure (ex. sponges)

radial symmetry: body can be divided into equal halves along any plane through the central axis, often adapted for floating or sessile lifestyles, sense environment from all directions(ex. jellyfish, sea anemones)

bilateral symmetry: body can be divided into mirror-image right and left halves along one plane only, enables directed movement and complex organ systems (ex. humans, worms, insects)

Use animal body plans to group Phyla

Animal phyla can be grouped by symmetry: asymmetrical (Porifera), radially symmetrical (Cnidaria), and bilaterally symmetrical (all other major phyla), with bilateral animals further classified by body cavity and development

Be able to correctly use the terms Metazoa, Eumetazoa, Bilateria, Deuterostomia, Lophotrocozoa, and Ecdyszoa to sort Phyla into clades. Also, be able to define those terms

how phyla fit into clades:

Metazoa: Everything (sponges, cnidarians, worms, mollusks, arthropods, echinoderms, chordates)

Eumetazoa: Everything except sponges

Bilateria: Everything except sponges and cnidarians

Deuterostomia: Echinoderms, chordates

Lophotrochozoa: Annelids, mollusks

Ecdysozoa: Nematodes, arthropods

pseudocoelomates

Have a false coelom → a body cavity partially lined with mesoderm (the inner side next to the gut is endoderm).

Provides some space for organs, but less organized than coelomates.

ex: roundworms

outer layer is ectoderm, middle layer is mesoderm, inner layer is endoderm and forms the gut, space inbetween gut and body is the pseudocoelom

acoelomates

No body cavity between gut and body wall.

organs are packed directly in solid tissue limiting movement and flexibility of internal organs

ex: flatworms

outer layer is ectoderm (skin and nervous system), middle is mesoderm (muscle, reproductive organs), inner is endoderm (gut)

porifera (sponges)

Symmetry: Asymmetrical

Tissues: None

Body Cavity: None

Other Features: Filter feeders, pores for water flow, mostly marine

ex: Grantia

cnidaria (jellyfish, anemones, corals)

Symmetry: Radial

Tissues: Diploblastic (ectoderm & endoderm)

Body Cavity: Gastrovascular cavity (single opening for mouth & anus)

Other Features: Stinging cells (cnidocytes), polyp or medusa body form

ex: Aurelia (jellyfish)

platyhelminthes (flatworms)

Symmetry: Bilateral

Tissues: Triploblastic

Body Cavity: Acoelomate (no body cavity)

Other Features: Flattened body, no circulatory system, diffusion for gas exchange

ex: Planaria

nematoda (roundworms)

Symmetry: Bilateral

Tissues: Triploblastic

Body Cavity: Pseudocoelomate (body cavity partially lined with mesoderm)

Other Features: Complete digestive system (mouth and anus), unsegmented

ex. Ascaris

annelida (segmented worms)

Symmetry: Bilateral

Tissues: Triploblastic

Body Cavity: Coelomate (true coelom, fully lined with mesoderm)

Other Features: Segmented body, closed circulatory system

ex: Earthworm (Lumbricus)

mollusca (snails, clams, squids)

Symmetry: Bilateral

Tissues: Triploblastic

Body Cavity: Coelomate

Other Features: Soft-bodied, often with a shell, muscular foot, visceral mass, mantle

ex: Octopus

arthropoda (insects, spiders, crustaceans)

• Symmetry: Bilateral

• Tissues: Triploblastic

• Body Cavity: Coelomate

• Other Features: Segmented body, exoskeleton made of chitin, jointed appendages

ex: Grasshopper

echinodermata (starfish, sea urchins)

• Symmetry: Radial as adults, bilateral as larvae

• Tissues: Triploblastic (three germ layers)

• Body Cavity: Coelomate

• Other Features: Water vascular system, endoskeleton, deuterostomes

ex: Starfish (Asterias)

chordata (vertebrates and some invertebrates)

• include fish, amphibians, reptiles, birds, and mammals

• Symmetry: Bilateral

• Tissues: Triploblastic

• Body Cavity: Coelomate

• Other Features: Notochord, dorsal hollow nerve cord, pharyngeal slits (throat openings; gills in fish, throat and ear parts in humans), post-anal tail, deuterostomes

ex: Human (Homo sapiens), sharks, etc.

metazoa

all multicellular animals

eumetazoa

animals that have true tissues (so sponges are excluded)

bilateria

animals that are bilaterally symmetrical and triploblastic (3 germ layers)

deuterostomia

bilateral animals in which the blastopore becomes the anus

lophotrochozoa

Protostomes with a lophophore feeding structure (crown of tentacles around the mouth) or trochophore larva (a free swimming, ciliated larval stage)

includes mollusks and annelids

ecdysozoa

Protostomes that molt a cuticle (ecdysis) (includes arthropods and nematodes)

Ctenphora

Symmetry: Radial

Tissues: Diploblastic

Body Cavity: Acoelomate (no body cavity)

Other Features: eight rows of ciliary plates (combs) for movement, no stinging cells.

ex. Mnemiopsis

Acoela

Symmetry: bilateral

Tissues: triploblastic

Body Cavity: Acoelomate (no body cavity)

Other Features: simple or no gut, no circulatory system

ex. acoel flatworm

Hemichordata

Symmetry: primarily bilateral

Tissues: triploblastic

Body Cavity: coelom

Other Features: Deuterostomes, pharyngeal slits, dorsal nerve cord (partial)

ex. saccoglossus

Platyhelminthes

Syndermata

Ectoprocta

Brachiopoda

Annelida