Topic 2: Animal Diversity pt 1 Flashcards
What are the 3 ways animals can be differentiated from plants and fungi?
- Nutritional mode: animals are heterotrophs that feed via ingestion 2. cell structure and specialization: animals are eukaryotic and mostly multicellular. They lack cell walls. Contain collagen. Specialized cells are organized into tissues (have muscle and nerve tissues). 3. Reproduction and development: mostly sexual, dominated by a diplontic life cycle (2N), only gametes haploid.
in animal development some animals (larvae) undergo
metamorphosis
much of animal form is controlled by
homeoboxes (which contain family of genes called: Hox genes)
define cleavage
a series of mitotic divisions
describe the steps of cleavage
After 3 divisions an eight-celled embryo is formed. Eventually a blastula is produced: a hallow ball of cells that surround a cavity called the blastocoel. Then Gastrulation occurs, folding one end of the embryo inward, expanding into the blastocoel. This produces layers of tissues: the ectoderm (outermost layer), & the endoderm (innermost). Then the archenteron (pouch formed by gastrulation opens to the outside via the blastopore. Which will develop into the end of the digestive tract. The endoderm (of the archenteron) then develops into the digestive tract.
what’s a body plan and what are some features that a body plan includes?
morphological and developmental traits integrated into a whole being. Includes: symmetry, tissues, and body cavities.
describe the types of symmetry
asymmetry: lack symmetry, radial symmetry: (circular), no sides or front/back, can be cut in half evenly many ways, often sessile organisms. Bilateral symmetry: two-sided symmetry, can only be cut in half evenly one way, often mobile organisms.
most bilateral animals have what, and describe it
cephalization (concentration of sensory organs and nerves, a brain)
What is the only animal that lacks tissues? What clade of their own are they in because they don’t have true tissues? what clade are other animals in that don’t have true tissues?
Sponges, they are in Parazoa, and other animals are in Eumetazoa.
Most animals have tissues (germ layers) because of gastrulation, describe the 3 layers
ectoderm: covers surface, mesoderm: fills the space between ecto- and endoderms, forming muscles and other organs, Endoderm: forms digestive tract
different animals have different numbers of germ layers what are the 2 variations and examples of each
diploblastic: two germ layers ex: Cnidarians. Triploblastic: 3 germ layers ex: all bilateral animals
body cavities
fluid filled spaces between the digestive tract and outer body wall
many triploblastic animals have what? what is it derived from
coelom, it is derived from the mesoderm.
what is the function of the coelom?
it cushions internal organs and acts as a skeleton in some worms.
Hemocoel
a body cavity that some triploblastic animals have, it is involved in internal circulation, nutrient transport, and hydrostatic skeletons. The fluid that is circulated is the hemolymph. (so all animals with an open circulatory system have a hemocoel)
whats an animal with both a coelom and hemocoel called?
A eucoelmate
what’s an animal with only a hemocoel called?
a pseudocoelomate (false coelom)
what’s an animal with neither coelom or hemocoel?
an acoelomate
Explain the 2 developmental modes (cleavage types, and mesoderm and blastopore fate)
- Protostome development: undergo spiral cleavage, and determinate cleavage (cell fates are determined early on). Solid mass of mesoderm splits to form the coelom, and the blastopore becomes the mouth (second opening becomes anus p=primary mouth 1st).
- Deuterostome development: undergo radial cleavage, and indeterminate cleavage (each cell retains the capacity to, in isolation, develop into a complete embryo). The mesoderm buds from the wall of the archenteron, and the cavity produced from the budding becomes the coelom, the blastopore becomes the anus, (second opening becomes mouth)
what was the common ancestor of all animals
a choanoflagellate
what clade are all animals in
metazoa
what animal branches off first (basal animal), what phylum and clade is this animal?
Sponges, phylum porifera, clade parazoa
what clade are all animals except sponges in because they have true tissues?
eumetazoa
what are the only phyla that are in the clade radiata and diploblastic
Ctenophora, and cnidaria
are bilateria triploblastic or diploblastic
triploblastic
what are the 3 major clades of bilaterians
deuterostomia, lophotrochozoa, ecdysozoa
what is the only phylum with vertebrates
chordates
what characterizes clade Deuterostomia what phyla are included? but what’s the exception
chordates and invertebrates (chordata, and Echinodermata), deuterostome development (but not all organisms developed by deuterostome development are deuterostomes.) And not all members have dorsal nerve cords and gill slits (they were lost in echinoderms).
what characterizes clade ecdysozoa, what phyla are included
Stepwise growth. Secrete exoskeletons (molt), in process called ecdysis. Includes: nematodes, and arthropods
what makes phylum nematoda different from annelida
they are round worms that lack segmentation, and covered in a tough cuticle that must be shed as the animal grows, they also lack a circulatory system
describe arthropoda core body plan and circulatory system and body cavity(s)
they have a segemented body, hard exoskeleton (made of chitin, must moult), and jointed appendages. Open circulatory and hemocoel, very reduced coelom.
what 5 clades are within phylum arthropoda
chelicerata, subphylum myriapoda, pancrustaceans, crustaceans, and hexapoda.
describe chelicerata clade (within arthropoda)
claw like chelicerae are pincers, no attennae, 2 segments, arachnids, gas exchange with book lungs, spiders can catch prey with silky webs.
describe subphylum of arthropoda: myriapoda
millipedes and centipedes, terrestrial, have antennae, lots of walking legs
what organisms are incuded in clade pancrustaceans within arthropoda
crustaceans and insects
describe crustaceans clade, organisms included, habitat, looks (within arthropoda)
crabs, lobsters, shrimps, barnacles, crayfish. marine, freshwater, and terrestrial. Specialized appendages: 2 pairs of atennae, 3+ pairs of mandibles, walking legs, swimmerets, sex appendages
describe clade hexapods organisms, habitat development and reproduction (within phylum Arthropoda)
insects, have 6 legs, live everywhere, undergo metamorphosis (stages), reproduction usually sexual and internal fertilzation.
what characterizes lophotrochozoa
Continuous growth, Invertebrates. Some have lophophores (crown of tentacles), some have trocophore developmental stage (molluscs and annelids), these structures are for feeding
how do sponges feed
They are suspension feeders, their choanocytes use flagella to circulate the water and pull in food particles, and trap food around base of its flagellum. The choanocyte engulfs bacteria and other food particles via phagocytosis.
what are amoebocytes made from and what do they do
made from calcium carbonate/ silica or spongin for skeletal support. These are cells that can transport nutrients to other cells of the sponge and make spicules (for skeletal support), also they can become any sponge cell type needed.
gastrovascular cavity
a central cavity with a single opening that functions both in digestion and distribution of nutrients.
what phylums have a gastrovascular cavity (aka one opening for mouth and butt)
cnidarians and platyhelminthes
describe the cnidarian nervous system
they have a rudimentary nervous sytem (no brain) to detect their surroundings
what are the two body forms of the cnidaria describe how they look, their movement and their feeding.
- Polyp (cylindrical, tentacles on top, looks like tree kinda), attaches to substrate by aboral (opp mouth), end. Mostly sedentary, tentacles extend to catch prey and pull it into gastrovascular cavity.
- Medusa (like upside-down polyp, umbrella shape, tentacles below), more mobile passive drifting. same feeding as polyp.
what are cnidocytes and nemocysts
cnidocytes line the tentacles and are armed with cnidae (coiled thread that is shot out to capture prey)
nemocysts are specialised cnidae that sting.
what are the two clades within cnidaria and their forms
anthozoans which only occur as polyps and medusozoans which can occur as polyps or medusa
what are the three groups within medusozoans
scyphozoans (jellies), cubozoans (box jellies), and hydrozoans.
how do cnidaria reproduce
specialized reproductive polyps (called gonzooids) produce small medusae by budding (asexual). These medusae then swim off, grow and sexually reproduce.
characteristics of flatworms
marine, freshwater, or terrestrial, triploblastic, acoelomate, incomplete gut, and gas/waste exchange via diffusion through skin.
what are the 3 clades within phylum platyheminthes
Free living (planarians), parasidic (trematodes, flukes), parasidic (cestotodes, tapeworms)
describe how planarians move, their nervous system and their reproduction
move via cilia on stomach, they have a more centralized nervous system (ganglia), Reproduce asexually via fission
or sexually as hermaphrodites
describe how trematodes reproduce
they require intermediate hosts to reproduce, reproductive organs take up most of the body
describe parasitic: cestodes (tapeworms)
their hosts are vertebrates, anterior end is scolex, lack mouth and gastrovascular cavity, nutrients via diffusion from host intestines
describe phylum rotifera habitats, gut, body cavity, feeding, size, reproduction
freshwater, marine and damp soil habitats, have complete gut (separate mouth and anus), hemocoel, ring of cilia on mouth to draw water in. Some undergo asexual reproduction called parthenogenesis.
describe phylum Ectoprocta looks, movement and development type, and habitat
(look like moss but animals) have lophophore, u shaped alimentary canal, true coelom, exoskeleton, sessile, deuterostome development, marine and freshwater.
describe phylum brachiopoda look, movement, development type, habitat
look like clams, sessile, deuterostome, marine
what are the 3 core body structures of phylum mollusca
foot: for movement, visceral mass: internal organs, mantle: secretes shell over visceral mass.
what type of body cavity do mollusca have
hemocoel but also a reduced coelom
how do mollusca feed
use their radula to scrape food off substrates
what are the 6 main phyla within lophotrochozoa?
platyhelminthes (flatworms), rotifera (rotifers), ectoprocta (like marine moss), brachiopoda (brachiopods), mollusca (snails, bivalves, cephalopods), annelida (segmented worms).
what are the four clades within mollusca, which one is the only one with a closed circulatory system
Gastropoda (most common 3/4), chitons, cephalopoda, bivalva. Cephalopoda only have closed.
clade chitons, describe their look habitat and feeding
they have oval-shaped unsegmented body with 8-plate dorsal shell, marine on rocks, feed on algae
clade gastropoda, describe their look habitat and feeding
snails and slugs, most have spiral shell to hide in, Marine, freshwater, terrestrial, poisinous radula to get prey.
clade cephalopoda, describe their look habitat and feeding
squids, octopus, cuttlefish, beak like jaw, siphon instead of foot. marine.
clade bivalva, describe their look habitat and feeding
clams, mussels, oysters, scallops. aquatic. no radula, filter feed with gills in mantle cavity.
describe phylum annelida look, body cavity, habitat
segmented worms, have coelom (no hemocoel), found in marine, freshwater and moist terrestrial habitats.
what are the two clades within phylum annelida and the differences between them
errantia are marine predators and grazers and highly mobila contain parapodia for movment. sedentaria burrow in soil/sedement they are less mobile and hairy
what 5 clades are within phylum echinodermata
asteroidea, ophiuroidea, crinoidea, echinoidea, holothuroidea
asteroidea describe (within echinodermata)
starfish, digestion occurs outside body, tube feet arms radiating from central disk, can regenerate lost limbs.
describe ophiuroidea (within echinodermata)
brittle stars, central disks with long slender arms, swim by thrashing about, tube feet.
clade crinoidea (within echinodermata)
sea lillies and feather stars. attach to substrate via stalk or slender arms.
clade echinoidea (within echinodermata)
sea urchins (spherical) and sand dollars (flat), no arms but 5 rows of tube feet. muscles to move and pivot spines. -jaw like structures for feeding on seaweed.
clade holothuroidea (within echinodermata)
sea cucumbers. lack spines, elongated along oral aboral axis, 5 rows of tube feet.
