Ch.33 - Invertebrates Flashcards
Invertebrates lack a backbone and comprise __% of all animal species.
Invertebrates lack a backbone and comprise 95% of all animal species.
Sponges are members of wh phylum
Porifera
Describe sponges in terms of habitat, tissue-composition, food sources.
Sedimentary, often mistaken for plants
Live in fresh and marine waters
Lack true tissues, but have many cell types
Suspension (filter) feeders
- capture food particles suspended in the water that passes thru their body
The _______ is the central cavity in sponges, where water enters thru pores and leaves thru an opening called the _______.
The spongocoel is the central cavity in sponges, where water enters thru pores and leaves thru an opening called the osculum.
_________ are flagellated collar cells that line interior of spongocoel.
Choanocytes are flagellated collar cells that line interior of spongocoel.
- Generate water current thru the sponge, ingest suspended food.
- Remarkably similar to choanoflagellate protists.
Sponges consist of a gelatinous noncellular _______ layer b/w two cell layers.
Sponges consist of a gelatinous noncellular mesohyl layer b/w two cell layers.
_________ are totipotent cells found in the mesohyl of sponges that play roles in digestion and manufacture of skeletal fibers
Amoebocytes are totipotent cells found in the mesohyl of sponges that play roles in digestion and manufacture of skeletal fibers
T/F: most sponges are hermaphrodites
TRUE
fxn as both male and female
typ sequential hermaphroditism, i.e. fxn first as one sex, then the other
Name a few species in the phylum Cnidaria
Jellies, corals, hydras
Sea wasps
Sea anemone
colonial polyps
Cnidarians have a relatively simple diploblastic, radial body plan and contain a sac w a central digestive compartment, called the ________.
Cnidarians have a relatively simple diploblastic, radial body plan and contain a sac w a central digestive compartment, called the gastrovascular cavity.
- I.e. single opening as mouth & anus
Two variations of Cnidarian body plans:
- A ______ adheres to the substrate by the aboral end of its body (sessile)
- A ______ has a bell-shaped body with its mouth on the underside (mobile)
Two variations of Cnidarian body plans:
- A polyp adheres to the substrate by the aboral end of its body (sessile)
- A medusa has a bell-shaped body with its mouth on the underside (mobile)
W/i the Cnidaria phylum, the clade ________ incl corals and anemones.
W/i the Cnidaria phylum, the clade Anthozoa incl corals and anemones.
- Occur ONLY as polyps.
_____ often form symbioses w algae and secrete a hard exoskeleton.
Corals (Cnidaria; Anthozoa) often form symbioses w algae and secrete a hard exoskeleton.
Ea gen grows on the skeletal remains of the prev gen, forming “rocks” that provide habitat for other species
Bilaterian animals have which type of symmetry and tri- or diploblastic dev?
Bilaterian animals have bilateral symmetry and triploblastic dev.
- Most have a coelom and a digestive tract with TWO openings
The clade bilateria incl wh three clades?
Lophotrochozoa
Ecdysozoa
Deuterostomia
Phlyum Mollusca belong to wh clade?
Lophotrochozoa
- Incl snails and slugs; oysters and clams; octopuses and squids
- Soft-bodied, but typ protected by a calcium carbonate shell
Phylum Annelids belong to wh clade?
Lophotrochozoa
Bodies composed of a series of fused rings
Three classes:
- Oligochaeta (earthworms and their relatives)
- Polychaeta (polychaetes)
- Hirudinea (leeches)
what are oligochaetes
class w/i phylum annelids, w/i clade Lophotrochozoa
Incl earthworms
Chaetae: bristles made of chitin
- Oligo = few, thus fewer chaetae than other classes of annelids
T/F: earthworms are hermaphrodites
TRUE
earthworms are simult hermaphrodites, but cross-fertilize
___________ is a group of protostome animals, including Arthropoda, Nematoda, and several smaller phyla.
Ecdysozoa is a group of protostome animals, including Arthropoda, Nematoda, and several smaller phyla.
Which animal group contains the most species?
Ecdysozoa
Contains phyla Arthropoda and Nematoda
What feature distinguishes Ecdysozoans?
Cuticle: tough external coat
Ecdysis: process by which the cuticle is shed or molted
Which phylum comprises 2/3 of all known animal species?
Arthropods comprise 2/3 of all known animal species
> 1 mil
The Arthropod body plan dates back to which distinct time period?
The Arthropod body plan dates back to the Cambrian explosion
Segmented body
Tough exoskeleton (cuticle)
Jointed appendages
The Arthropod body plan dates back to the Cambrian explosion and is distinguished by a segmented body, tough exoskeleton (cuticle), and jointed appendages.
How did these features change over evolutionary time?
Decrease in # of segments
Increase in appendage specialization
Adaptations may have resulted of changes in Hox gene sequence or regulation
What is an Arthropod’s cuticle comprised of?
Protein
Layers of chitin (polysac)
What are the four major lineages (subphyla) of Arthropods?
Cheliceriforms (horseshoe crabs, spiders)
Myriapods (millipedes, centipedes)
Hexapods (insects)
Crustaceans (pill bugs, shrimp, lobster, crayfish)
_________ include echinoderms, hemichordates and chordates
Deuterostomes include echinoderms, hemichordates and chordates
Based mainly on DNA evidence, but all have similar dev characteristics
Echinoderms, a phyla of Deuterostomia, are slow or fast moving?
Echinoderms are slow-moving or sessile marine animals
E.g. starfish
Describe the exterior of Echinoderms (starfish)
thin epidermis over a hard endoskeleton of calcareous plates
Describe the water vascular system in Echinoderms (starfish; Deuterostomia)
water vascular system: network of hydraulic canals
Branch into tube feet, fxn in locomotion, feeding, and gas exchange
Are male and female Echinoderms (starfish, Deuterostomia) typ separate or hermaphroditic?
Does sex reprod occur internally or externally?
Males and female Echinoderms are typ separate
External sexual reproduction
Sea urchins and sea cucumbers belong to which phylum?
Echinoderms (Deuterostomia)
Phlym Cordata belongs to which group?
Deuterostomia
Closest relatives: hemichordata, Echinodermata (starfish)
Phylum Chordata consists of which two basal groups of __________ as well as _________.
Phylum Chordata consists of which two basal groups of invertebrates as well as vertebrates.
Chordates are _________ (radially or bilaterally) symmetrical ________ (pseudo- or coelomates) w segmented bodies
bilaterally symmetrical coelomates w segmented bodies
Did Chordates evolve separately or from Echinoderms (starfish)?
Chordates did not evolve from Echinoderms, but have evolved separately from them for at least
500 million years
T/F: All deuterostomes have a pseudo coelom
FALSE
All deuterostomes do NOT have a pseudo coelom
T/F: The animal kingdom in monophyletic
TRUE
The animal kingdom in monophyletic; all derive fr Metazoa clade
T/F: A Lophophore is a feeding structure
TRUE
A Lophophore is a feeding structure
Diff b/w coelomates and pseuodcoelomates
Coelomates have a body cavity completely lined by mesodermal tissue, whereas pseudocoelomates have no such tissue
The blastopore first became evident during which stage of development?
The blastopore first became evident during gastrulation
Embryo eight-cell stage:
- radial or bilateral cleavage
- determinate or intermediate cleavage
- applies to deuterostomes or protostomes
- Give an example
Embryo eight-cell stage is radial cleavage, intermediate cleavage, applies to deuterostomes, e.g. humans.
Which traits are found in Chordates, and what do they form in humans?
Muscular post-anal tail - forms coccyx/ tailbone in humans
Notochord - forms cushioning disc b/w vertebrae in humans
Dorsal, hollow nerve cord - forms brain/SC in humans
Phalangeal slits/ clefts - form ears/nose in humans
Bilateria consists of which three groups?
Bilateria consists of three groups: Lophotrochozoa, Ecdysozoa, Deuterostomia
