College bio- unit 4

Blastula

A multicellular hollow stage resulting from cleavage during animal development.

Gastrula

Stage following blastula where adult body parts are produced through gastrulation.

Germ Layers

Tissues that form during development, including endoderm, ectoderm, and mesoderm.

Coelom

Body cavities in animals, categorized as pseudocoelomates or acoelomates.

Radial Symmetry

circular. no head or rear, no left or right

Asymmetry

no symmetry

bilateral symmetry

defined left & right side

endoderm layer

innermost

ectoderm

outermost, covers surface

mesoderm

not in all

pseudo coelomates

animals with pseudocoelom (body cavity)

acoelomates

no body cavity

Protostomes spiral

mouth develops from blastopore

deuterostome radial

anus develops from blastopore

medusa

flattened, mouth down form- sexual

polyp

cylindrical forms- asexual

1- sponge

• 5,000 species

• suspension feeders

• 2 layers

• aquadic

• reproduce asexually by fragmetation

• reproduce sexually by eggs & sperm

• only animals digestion occurs within cells

mesohyl

galetinous region that separates sponge layers

2- Phylum Cnidarians

• 9,000 species

• radial symmetry

• gastrovascular cavity (single opening)

• polyp and medusa stage

• groups

  • hydrozoans- alternate between polyp & medusa

  • scyphozoans- medusa stage. ex: sea jellies

  • cabozoans- medusa stage, complex eyes. ex: sea wasp

  • anthozoans- flower animals, polyp. ex: coral, sea anemones

• sting cells called cnidocytes

• nerve net

• two tissue layers

• radial symmetry

Phylum Cnidarians- hydrozoans

obelia

Phylum Cnidarians- scyphosoans

sea jellies

Phylum Cnidarians- cabozoans

sea wasps

Phylum Cnidarians- anthozoans

coral, sea snemones

3- Phylum Platyhelminthes

• 13,000 species

• live in marine

• no organs for gas exchange

• one opening in gastrovascular cavity

• groups

  • turbellarians- asexual. ex: planarians

  • monogeneans/trematodes- mostly parasites. ex: blood flukes

  • cestodes- parasites. ex: tapeworm

• free living or parasites

• most are parasites

• planaria are free living and hermaphroditic

Phylum Platyhelminthes- turbellerians

planarians

Phylum Platyhelminthes- monogeneans/trematodes

blood flukes

Phylum Platyhelminthes- cestodes

tapeworms

Phylum Nematoda

pig roundworms

Phylum Nematoda

hook worm

Phylum Nematoda

pinworm

Phylum Nematoda

filarial worms

4- Phylum Rotifera

• 2,000 species

• very tiny (2mm)

• specialized organ systems

• limentary canal with head end ( mouth and anus)

• parthenogenesis 

• abundant in fresh water and microscopic in size

5- Phylum Nematoda

• 500,000 species

• generally colorless and found everywhere

• some are predators, some are free living, some are parasites

• Pig Roundworms, Hook worms, Filarial worms and Pinworm

6- a colelom

• all protostomes are bilaterally symmetrical and have 3 germ layers

• a tube within a tube body plan

• they have a true coelom which is a body cavity lined by mesoderm.

• with a coelom the digestive system and body wall can move independently and internal organs can be more complex.

• protostomes have spiral cleavage and a blastophore associated with the mouth

7- phylum mollusca

• 110,000 species

• most marine but some terrestrial

• most have open circulatory system

• many have shell

• groups

  • bivalves- oysters, mussels & scallops

  • cephalopods- squids, cuttlefish & octopus

  • gastropods- snails, whelks, conchs, periwinkles & sea slugs

phylum mollusca- bivalaes

clams

phylum mollusca- bivalaes

oysters

phylum mollusca- bivalaes

mussels

phylum mollusca- bivalaes

scallops

phylum mollusca- cephalopods

squid

phylum mollusca- cephalopods

cuttlefish

phylum mollusca- cephalopods

octopus

phylum mollusca- cephalopods

nautilus

phylum mollusca- gastropods

snails

phylum mollusca- gastropods

periwinkles

phylum mollusca- gastropods

sea slugs

phylum annelida- oligochaetes

earthworms

phylum arthopoda- cheleicerates

spider

phylum arthopoda- cheleicerates

scorpions

phylum arthopoda- cheleicerates

ticks

phylum arthopoda- cheleicerates

mites

phylum arthopoda- cheleicerates

sea spiders

phylum arthopoda- crustacea

shrimp

phylum arthopoda- crustacea

lobsters

phylum arthopoda- crustacea

crayfish

phylum arthopoda- myriapoda

millipede

phylum arthopoda- myriapoda

centipedes

8- phylum annelida

• 12,000 species

• segmented worms

• groups

  • marine polychaetes- some are attached some are free living

  • oligochatetes- earthworms, live in soil

  • leeches- parasitic, used to be medicine

9- phylum arthropoda

• over 1,000,000 species

• jointed appendages

• well-developed nervous system

• groups

  • chelicerates- 4 pairs of walking legs, book lungs, ex: spiders, scorpions, ticks & mites

  • crustacea- hard shell exoskeleton, 5 pairs of appendages, ex: shrimp, lobster & crayfish

  • myriapoda- live on land, breathe through tracheae, ex: millipede & centipede

  • insecta- many separate groups, specialized for specific life styles

Deuterostomes

animals which the second embryonic opening is associated with the mouth

10- phylum echinodermata

• radial symmetrical as adults

• bilateral symmetrical as juveniles

• classes

  • Crinoidea- nonmotile sea lilies, motile feather stars

  • Holothuroidea- sea cucumbers

  • Echinoidea- sea urchins, sand dollars

  • Ophiuroidea- brittle stars

  • Asteroidea- sea stars

Class Crinoidea

sea lillies

Class Holothuroidea

sea cucumbers

Class Echinoidea

sea urchins, sand dollar

Class Ophiuroidea

brittle stars

Class Asteroidea

sea stars

phylum chordata characteristics

• a dorsal supporting notochord

• a dorsal hollow nerve cord

• pharyngeal pouches

11- phyilm chordata

• 45,000 species

• groups

  • phylum hemichordata- not considered chordates but have chrodate features, ex: acorn worms

  • subphylum urochordata- only gills slits in adult, ex: sea squirts

  • subphylum cephalochordata- resemble a lancelet, retain all 3 chordate characteristics as adults

Vertebrate Evolution

- at some time in their life all vertebrates have the 3 chordate characteristics

-  closed circulation, complete digestive tract

- all with a head are called craniates

Hagfish

jawless, not true fish

lampreys

jawless

Cartilaginous Fish

shark, skates and rays

oviparaous

eggs are released to outside

ovoviviparous

retain eggs in oviduct

viviparous

yolk sak palcenta

bony fish

swim blatter, some can move from salt to fresh

lung fish

live in stagnant water or ponds that dry up

coelacanths

once thought extinct, live in deep ocean

12- amphibians

• 3,900 species

• stay close to water

• lungs are underdevoloped

• fertilization is external in some and internal in others

• ectothermic

• ex; frog toads and salamanders

ectotherms

depend on environment for temperature control

13- reptiles

• 6,000 species

• most live in the tropics

• good lungs

• nearly 4 camber heart

• well developed kidneys

• ectothermic

• ex: snake, turtle, alligator and croc

14- birds

• all have feathers

• almost every anatomical feature can be related to their ability to fly

• classification is based on beak, foot, habitat and behavior

• hard shell eggs

• homeothermics

15- mammals

• 4,500 species

• hair and mammary glands

• Monotremes have a cloaca and lay hard shelled eggs

• Marsupials begin development  in mother and are born very premature

• Placentals  give birth to live young

monotremes

have a cloaca and lay hard shelled eggs

marsupials

begin development in moth and are born very premature