Biology Ch 27: Animal Diversity

Plesiomorphic characters with prokaryotes

metabolism, plasma membrane, ribosomes

Synapomorphic characters with plants

sexual reproduction, meiosis

Synapomorphic characters with fungus

heterotrophy

animal cells and tissues

no cell wall, gap junctions, bone matrix (sometimes), vertebrae have connective tissue, epithelial tissue

connective tissue

includes living and non-living cells, supports body structure

epithelial tissue

covers and protects internal organs and external body structures

muscle tissue

facilitates movement

nervous tissue

receive and transmit electrical impulses

specialized systems in animals

digestive, sensory, nervous, muscular, skeletal

porifera

sponges

placoza

parasitic amoeba-like animals

cnidaria

jellyfish and relatives

ctenophores

comb jellies

bilateria

everything else (includes vertebrae)

body plan

focuses on body symmetry

embryonic development

number of germ layers, presence/absence of internal body cavity, origin of mouth and anus

diplontic life cycle

a life cycle in which the diploid phase (somatic cells) is multicellular, and the haploid phase (gametes) is unicellular

sexual reproduction

One haploid sperm fuses with one haploid egg, resulting in one diploid cell (zygote)

zygote cleavage

cells divide into smaller and smaller cells

eight-cell blastomere

Three mitotic divisions result

bastula

cleavage continues, and cells rearrange to create a hollow

bastocoel

the central cavity of the blastula

gastrulation

continued cell division and rearrangement, leads to gut cavity and embryonic layers

homeotic genes

determine embryonic development

Hox genes

DNA sequences on homeotic genes, determine animal body plan, undergo 2-4 duplication events

Hox genes in invertebrates

1 set

Hox genes in vertebraes

4 sets

diploblastic

two germ layers (ectoderm and endoderm), asymmetrical

triploblastic

three germ layers (ectoderm, endoderm, mesoderm), bilaterally symmetrical

ectoderm

covers surface of animal

endoderm

forms digestive tract, respiratory tract, and urinary tract

mesoderm

forms muscle, bone, circulatory system, etc.

asymmetrical

absence of symmetry

radial symmetry

arrangement of body parts from the central point, top and bottom, no head or tail, no directional movement, (typically diploblastic)

bilateral

a single plane divides the body into left and right sides that mirror, have a head and tail, cephalization, directional movement, and streamlined motion, triploblastic

cephalization

organized nervous system at anterior end

coelom

internal body cavity derived from mesoderm tissue

acoelomates

tripoblasts that do not have a coelom

eucoelomates

tripoblasts that have a coelom completely surrounded by mesoderm tissue

psuedo-coelomates

triplobasts that havr a coelom that is lined partly with mesoderm and partly endoderm

protosomes

blastopore becomes mouth

Deuterostomes

blastopore becomes anus