Animal Phylogeny

Animal Phylgeny unit for AP Bio

Characteristics of Animals

multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers

nutritional mode

heterotrophs by ingestion

Cell Structure and Specialization

multicellular eukaryotes;  lack cell walls

collagen

structural protein that holds together the bodies of animals.

unique animal features (tissues)

nervous and muscle tissue

reproduction and development

most reproduce sexually, diploid stage usually dominates life cycle.

larva

sexually immature and morphologically distinct from adult, undergoes metamorphosis to develop. Present in most animals.

homeoboxes

regulatory genes that code for transcription factors; regulate expression of other genes and contain sets of DNA sequences

Hox genes

regulate development of body form (morphology)

choanoflagellates

protists that are the most closest living relatives of animals

body plan

the set of traits defining a group of animal species. can be used to characterize animals.

sessile

organism is immobile, attached to something

radial symmetry

no left or right side

bilateral symmetry

two sided symmetry - normally have a dorsal (top or back) and ventral (bottom or belly), anterior and posterior, and right and left side.

cephalization

development of head

true tissues

collections of specialized cells isolated from other tissues by membranous layers

gastrulation

formation of embryonic tissue layers and a gastrula

Ectoderm

germ layer covering the embryo’s surface; gives rise to outer covering in animal (and maybe nervous system in some phyla)

Endoderm

innermost germ layer; gives rise to lining of digestive tract and other organs like liver and lungs

mesoderm

gives rise to muscles and other organs between digestive tract and outer covering

Diploblastic

animals that have ectoderm and endoderm

Triploblastic

animals that also have an intervening mesoderm layer

coelum

true body cavity; derived from mesoderm. may be present or absent in triploblastic animals.

pseudocoelum

A body cavity derived from the mesoderm and endoderm

Acoelomates

organisms without body cavities

Protostomes

mouth forms first (from blastopore); Found in arthropods, annelids and molluscs

Deuterostomes

mouth forms after anus (from blastopore). Found in echinoderms and chordates

protostome development

cleavage is spiral and determinate

deuterostome development

cleavage is radial and indeterminate

schizocoelous development

the splitting of solid masses of mesoderm to form the coelomic cavity in PROTOSTOMIC DEVELOPMENT.

enterocoelous development

formation of the body cavity in DEUTEROSTOMIC DEVELOPMENT.

Ecdysozoans

Shed their exoskeletons through a process called ecdysis (molting). Includes arthropods and nematodes

Lophotrochozoans

Either have a lophophore (feeding structure) or go through a larval stage called that trochophore larva.

cryoprotectants

antifreeze compounds

torpor

physiological state in which activity is low and metabolism decreases

hibernation

long-term torpor that is an adaptation to winter cold and food scarcity

estivation

enables animals to survive long periods of high temperatures and scarce water supplies

gastrovascular cavities

digestion and distribution of substances throughout the body in Cnidaria

components of all circulatory systems

circulatory fluid, set of tubes, and a muscular pump

open circulatory system

no distinction between blood and interstitial fluid, and this general body fluid is more correctly called hemolymph (fluid + salt ions + immune system cells)

closed circulatory system

blood is confined to vessels and is distinct from the interstitial fluid; are more efficient at transporting circulatory fluids to tissues and cells

Conodonts

first vertebrates with mineralized skeletal elements in their mouth and pharynx

Gnathostomes

have jaws that evolved from skeletal supports of the pharyngeal slits

Enhanced sensory systems, including the lateral line system

An extensively mineralized endoskeleton

Paired appendages

Temporal Fenestrae

Openings (windows) in temporal