Chapter 30 An introduction to animal diversity Flashcards
animal characteristics
- Multicellular eukaryotes
- heterotrophs
- specialized body cells
- diverse body plans
- most are capable of locomotion at some time during their life cycle
- most have nervous systems and muscle systems that enable them to respond rapidly to stimuli in their environment
- diploid and reproduce sexually, with large, nonmotile eggs and small, flagellate sperm
- most go through a period of embryonic development
The animal ___ undergoes cleavage and develops into a ___
The animal zygote undergoes cleavage and develops into a blastula
some animals develop directly into ___
adults
many animals develop into a ___, which may differ from the adult in appearance, habitat, how i moves and what it eats
larva
most ___ go through ___; juvenile form grows into an adult form
larvae fo through metamorphosis
advantages of a marine habitat
- Bouyancy of sea water provides support
- temp relatively stable
- same osmotic concentration
- plankton provides a ready source of food
disadvantages of marine habitat
the continuous motion of water
disadvantages of freshwater habitat
- Fresh water is hypotonic to the tissue fluids of animals, (animals require mechanisms for osmoregulation)
- animals must have adaptations for surviving variations in oxygen content, temp, turbidity, and water volume
- generally contains less food than the sea
Disadvantages of terrestrial life
- desiccation
- Gametes and developing offspring must be protected from dessication
- must have a skeletal system and muscle that support the body on land
- must have behavioral and physiological adaptations for maintaining body temperature
desiccation
the process of drying
Choanoflagellates, fungi, and animals are ___
opisthokonts that share a colonial flagellate (choanoflagellate) ancestor
changes in animal body plan are linked to changes in
patterns of embryonic development
many ___ that direct early development of the body plan have been ___ during animal evolution
genes…conserved
Many early ___ have similar genes and appearances
Many early embryos/fetuses have similar genes and appearances
___ development can infer relationships among animal groups
Embryonic
molecular comparisons of ___ and ___ help reconstruct animal phylogeny
molecular comparisons of nucleic acid and protein structure help reconstruct animal phylogeny
radial symmetry
general form of a wheel, arranged as spokes from a central axis
radial symmetry is found in
cnidarians and echinoderms
bilateral symmetry
found in most animals
divided through only one plane to produce right and left halves that are mirror images
Cephalization
the development of a head where sensory structures are concentrated
tissues
groups of closely associated, similar cells that work together to carry out specific functions
germ layers
cell layers formed in early development of all animals, except sponges, that develop into specific types of tissues (ectoderm, endoderm, mesoderm)
Cnidarians and ctenophores are
diploblastic
diploblastic
have only two tissue layers (ectoderm and endoderm)
animals other than Cnidarians and ctenophores are triploblastic
have all three germ layers
Blastula
hollow ball of cells
this is where sponges stop
Gastrula
two-layered stage where Cnidarians stop
Ectoderm
outer layer
Endoderm
invaginates to form gastrocoel (the cavity formed w/ opening called blastopore)
Mesoderm
during gasatrulationi some cells migrate inward to form a 3rd layer between the endoderm and ectoderm
diploblastic
All Cnidaria have two layers of cells
triploblastic
Other animals have three layers of cells
external ectoderm
- skin
- skin glands
- hair
- nails
Neural Crest
- facial cartilage
- pigment cells
- ganglia of autonomic nervous system
- dentin of teeth
- spiral septum of heart
- ciliary body of the eye
Neural Tube
- Brain
- spinal cord
- retina
- posterior pituitary gland
In sum the Ectoderm is
skin and nervous system
the mesoderm is
key to complex animals
mesoderm develops into
- bones
- connective tissue
- majority of circulatory system
- Gastrointestinal tract
- muscles
- peritoneum
- urinary system
- reproductive system
Endoderm develops into
- epithelial tissues of the gut
- respiratory system
- auditory system
Most bilateral animals have a fluid-filled ___ between the outer wall of the body and the digestive tube
body cavity (coelom)
Acoelomates
flatworms and ribbon worms
have no body cavity
True coelomates
have a body cavity that is completely lined with mesoderm
Pseudocoelomates
have a body cavity that is not completely lined with mesoderm
eumetazoa
Animals with two or three germ layers (diploblastic or triploblastic)
Bilateria
animals with bilateral symmetry
tiploblastic
Three major clades bilateral animals
- Deuterostomia
2. Protostome
two protostome clades
Lophotrochozoa
Ecdysozoa
Lophotrochozoa
Characterized by a ciliated ring of tentacles surrounding the mouth (lophophore) or a trochophore larva
Lophotrochozoa includes
flatworms, ribbon worms, mollusks, annelids, and the lophophorate phyla
Ecdysozoa
animals that undergo molting (ecdysis)
Ecdysozoa includes
nematodes and arthropods
