BSC 2011 Chapter 27 Animal Diversity

Diplontic

diploid phase is multicellular, haploid phase is unicellular

Embryonic developmental stages

fixed body plan, same development stages

Connective Tissue

both living and nonliving cells, supports body structure, not all animals

Epithelial Tissue

outside covering, protects internal organs

Muscle Tissue

facilitates movement

Nervous Tissue

receive and transmit electrical impulses

Porifera

sponges

Placazoa

parasitic animals

Cnidaria

jelly fish and relatives

Ctenophores

comb jellies

Bilateria

everything else

Cleavage

occurs to zygote where cells divide into smaller and smaller cells

Eight cell blastomere

mitotic divisions result in

Blastula

hollow ball of cells

Gastrulation

forms a gut cavity (archenteron) and germ layers

Ectoderm

outside layer (skin)

Endoderm

inside (gastro)

Mesoderm

middle, not all animals have this

Hox (Homeobox) genes

determine body makeup/directionality, then encode transcription factors

Transcription Factors

genes needed for specific things only turn on by cells and transcription factors when needed

Hox genes (master control genes)

determines animal body plan, head/tail directionality and number of body segments

Invertebrates

one set of hox genes, less complicated

Vertebrates

have four sets of hox genes, more complicated

Diploblastic

two germ layers- endoderm and ectoderm; asymmetrical and symmetrical

Ectoderm

covers surface of animal

Endoderm

forms wall of digestive tract

Triploblastic

three germ layers- ectoderm, endoderm, mesoderm; bilaterally symmetrical animals

Asymmetrical

most simple, no symmetry; placazoa and porifera w/ no true tissues

Radial Symmetry

arrangement of body parts from one central point, top and bottom; receives info from all directions (DIPLOBLASTIC)

Bilateral Symmetry

a single plane that divides the body into two, have a head and tail- cephalization; TRIPLOBLASTIC

Coelom

internal body cavity derived from mesoderm tissue, provides cushioning to internal organs

Acoelomates

triploblasts with no coelom, mesoderm completely filled with tissue

Eucoelomates

triploblasts that have a coelom that is completely surrounded by mesoderm

Pseudocoelomates

triploblasts that have coelom that’s lined partly with mesoderm and partly with endoderm- not surrounded on all sides 

Blastopore

hole in the blastula which either becomes the mouth or anus 

Protosomes

when the blastopore becomes the mouth, which is more primitive

Deuterostomes

the blastopore becomes the anus, first hole is the anus (in VERTABRATES)