vertebrate zoology chapter 2 terms

taxonomy of vertebrates

- Domain: Eukarya

- Kingdom: Animalia

- Phylum: Chordata

subphyla of invertebrates

- Urochordata

- cephalochordata

subphylum of vertebrates

Craniata

features leading up to Chordata

- bilateria (has 2 halves)

- coelomata (has a body cavity/coelom)

- deuterostomata

cephalization

development of a head

dorsal and ventral sides (bilateral symmetry)

top and bottom

anterior and posterior (bilateral symmetry)

front and back

coelom

space around the gut

eucoelom (coelomate)

“true” coelom

pseudocoelom (psuedocoelomate)

body cavity derived from the mesoderm and the endoderm

no coelom (acoelomate)

- simplest form

- has no gaps

cleavage

zygote undergoes rapid cell division after fertilization

blastula

cleavage leads to formation of hollow ball

gastrulation

blastula forms a gastrula (digestive tract) with different layers of embryonic tissues: endo-, ecto-, and mesoderm (triploblastic)

protostome

- blastopore becomes mouth

- cleavage is spiral and determinate (fate of each cell is already determined)

deuterostome

- blastopore becomes anus

- cleavage is radial and indeterminate (allows for cloning)

characteristics that define phylum Chordata

- pharyngeal slits or clefts

- notochord

- dorsal, hollow nerve cord

- muscular, post-anal tail with segmented muscles

- endostyle

pharyngeal slits or clefts

functions in suspension-feeding, gas exchange, develop into parts of the ear, head, and neck in tetrapods

notochord

- skeletal support

- adult often retains only remnants

dorsal, hollow nerve cord

develops into CNS

muscular, post-anal tail with segemented muscles

many lose this during embryonic development

endostyle

- glandular groove of the pharynx

- hormone producing gland

- precursor to the thyroid gland

cephalochordates

- marine, fishlike

- common = lancelets or amphioxus (sharp at both ends

- have myomeres

- have cerebral vesicle

- retain chordate features in adults (similar circulatory features, podocytes with chordates)

myomeres

- striated muscle fibers covered with connective tissue along side of body

- appear in clusters

cerebral vesicle

- thickening at anterior end of spinal cord

- have genes that code for vertebrate brain

podocytes

cells specialized in getting rid of waste

urochordates

- tunicates

- undergo metamorphosis

- free-living larvae “tadpoles” with all 4 chordate features

- adults lose most of tail, notochord, nerve cord but retain pharyngeal gill slits

- tunic is made primarily from cellulose

tunicates

marine, filter feeders as adults

cellulose in animals

thought to be a result of horizontal gene transfer from ancient bacteria

Cambrian Chordates

- fossil evidence from Haikouella in China

- large brain

- clearly defined eyes

- thickened branchial bars (“gills”)

- no skull or ears

what distinguishes a vertebrate

- all vertebrates have cranium (skull) that surrounds brain

- head usually with complex sense organs, segmented brain

- endocrine glands: thyroid (endostyle), pituitary gland

- muscular gut tube

- multi-chambered heart

- mineralized tissues to create rigid support structures or surfaces (ex: teeth)

- gills

pituitary gland

produces and regulates hormones

hox gene duplication

- regulate expression of other genes that control development along length of organism

- generate more complex animals

neural crest cells

- “4th germ layer” in addition to endo-, ecto-, mesoderm

- embryonic tissue that forms many structures

placodes

patches of thickened ectoderm

neurogenic placodes

- specialized regions of embryonic ectoderm that are central to the development of the cranial sensory systems

- olfactory, optic, lateral lines, trigeminal (facial nerves), and epibranchial (peripheral nerves)

number of sets of hox genes in invertebrates and amphioxus

1 set

number of sets of hox genes in living jawless vertebrates

2 sets

number of sets of hox genes in all jawed vertebrates

4 sets

4 types of tissues

- epithelial

- connective

- muscle

- nervous

epithelial tissue

covers body surfaces and lines organs

connective tissue

supports and connects body parts (bone, blood, fat)

muscle tissue

contracts to create movement

nervous tissue

sends electrical signals throughout the body

cartilage

- firm but flexible tissue

- softer than bone (think ear or nose)

bone

hard, rigid tissue that forms the skeleton

perichondral bone

bone that forms around cartilage

cementum

thin layer anchoring a tooth to the jaw

enamel

the hard outer coating of a tooth

dentine

the softer layer just beneath enamel, makes up most of the tooth

cloaca

- a single opening used for waste, urine, and reproduction

- common in fish, amphibians, birds

nephrons

tiny filtering units inside the kidney that clean the blood

oviduct

the tube that carries eggs from the ovary (like a fallopian tube)

diencephalon

- the middle part of the brain

- controls hormones and senses

telencephalon

- the front part of the brain

- handles thinking and behavior

cerebrum

the large, wrinkled brain region responsible for thought and movement

cerebellum

the smaller region at the back of the brain that controls balance and coordination

pineal gland

a small brain gland that detects light and regulates sleep cycles

rods/cones

- light-detecting cells in the eye

- rods detect dim light, cones detect color

neuromast organs

sensory cells (mainly in fish) that detect water movement

cochlea

the spiral structure in the inner ear that converts sound vibrations into nerve signals