Animals Flashcards
Heterotrophy
- ancestral trait of all animals
- depend on producers for energy
- ingest and digest internally
What are the two ancestral characteristics for animals?
eukaryotic and no cell wall
what are the four shared derived traits for animals?
A1 - Multicellular
A2 - Extracellular matrix
A3 - Early Embryonic Development Pattern
A4 - Homeobox Genes
describe the shared derived trait, extracellular matrix
- proteins are around cell membrane
- connects and supports cells, mostly made of collagen
describe differentiated cells in animals
- have specialized functions
- (most have) differentiated tissues = groups of cells with common structure and function
- (many have) differentiated organs = specialized structures made up of tissues
describe reproduction and development within animals
- usually sexual
- diploid dominant
- meiosis produces haploid sperm or egg
- fertilization: small flagellated sperm fuses with larger non-motile egg
describe the shared derived trait, early embryonic development pattern
- relates development pattern to phylogeny
- cleavage: mitotic divisions without growth
- blastulation: cell migration, forming a hallow ball of cells
- blastula: hallow ball of cells surrounding blastocoel (empty space)
- gastrulation: process of inward folding of blastula
- gastrula and germ layers
how is development regulated by genes?
homeobox genes
describe the shared derived trait, homeobox genes
- code for proteins that regulate expression of developmental genes
- control expression of many genes
- ex. hox genes
symmetry
arrangement of body structure in relation to axis of body
asymmetry
no plane of symmetry through body
what are the types of symmetry
radial and bilateral symmetry
radial symmetry
any plane through longitudinal axis (e.g. mirror images)
bilateral symmetry
one plane through longitudinal axis (e.g. mirror images)
- related to cephalization: development of a head with a CNS and sense organs
- facilitates complex movement
what are the different bilateral animal axes?
- left/right
- dorsal/ventral
- anterior/posterior
germ layers
concentric layers of embryonic tissue
ectoderm
outside layer
-outer covering NS
endoderm
inner layer
-lines digestive tube, other organs (lungs)
mesoderm
middle layer
-everything else
diploblasts
only have endoderm and ectoderm
triploblasts
have endoderm, mesoderm, and ectoderm
do body cavities apply to diploblasts, triploblasts, or both?
triploblasts only
coelom
body cavity - fluid filled space between body wall and digestive tube
Acoela
no coelom
what phyla is a true coelom ancestral to?
5-12, Echinodermata - Arthropoda
acoelomate
- flat
- filled in coelom
- had a coelom, but it doesn’t work anymore (ancestral)
pseudocoelomate
-use coelom as a hydrostatic skeleton (support, movement)
coelomate
- ancestral trait
- true coelom
what are the advantages to a coelom?
- hydrostatic skeleton: support, movement
- circulation: no longer need to be flat
- no cavity? diffusion from outside - SA:V problem
what are the two basic modes of animal development?
protostomes and deuterostomes
what are the three traits animal development is based on?
- cleavage
- coelom formation
- fate of blastospore
what event happened that allowed the three traits of animal development to appear? explain.
the Cambrian Explosion
~500 - 540 mya
-1st appearance of many body plans in fossil record
-1st evidence of hard body plans
-many extant phyla appear, many others now extincct
character
specific unique development pattern
give an example of an ancestral character state
protostome
describe protostome development
- ancestral mode of animal development
- spiral, determinate cleavage
- coelom from masses of mesoderm
- blastospore -> mouth (protostome = “1st opening”)
describe deuterostome development
- derived development mode in some animal groups (appeared several times)
- radial, indeterminate cleavage
- coelom from folds of archentron (ancient intestine)
- blastospore -> anus (deuterostome = “2nd opening”)
what is the sister taxon to animals? describe
choanoflagellates
- flagellated, unicellular
- extremely similar to choanocytes of sponges (basal animals)
- similar cells found in other animals, not other groups
is the Metazoa Clade mono-, para-, or polyphyletic?
Monophyletic
What does ‘Eumetazoa’ mean?
true animals
What are the shared derived traits of eumetazoa?
- diploblast tissues
- radial symmetry
what are the ancestral traits of eumetazoa?
multicellularity, heterotrophy, ECM…
what are the shared derived traits of Bilateria?
- triploblast tissues
- bilateral symmetry
describe bilateria (excluding the SDTs)
- most animal phyla
- almost all share coelomate ancestor
- rapid diversification during Cambrian Explosion
what are the three major clades within Bilateria?
Deuterostomia, Lophotrochozoa, and Ecdysozoa
Deuterostomia
SDT: deuterostome development
remember, some with deuterostome development outside this group
what is Lophotrochozoa made up of?
entirely invertebrates
what is the SDT of Lophotrochozoa?
genetic similiarities (grouped based on DNA)
what is the SDT for the Ecdysozoan clade?
ecdysis: molting/shedding exoskeleton/cuticle
