Chapter 31 Flashcards
Protostome animals
What are the two branches of protostomes?
Lophotrochozoa and Ecdysozoa
What are the importance of protostomes
- Major source of food for humans
- Pollination, soil preparation
- Include insects that damage and protect crops
- Provide valuable materials (silk, pearls)
- Common parasites (transmit human diseases)
- Include vital model organisms like fruit fly and Roundworm
What are the general characteristics of all protostomes?
- Bilaterally symmetric
- Tripoblastic
- Gastrula pore becomes mouth
What are the phyla included in Lophotrochozoa
- Rotifera
- Platyhelminthes
- Aneelida
- Mollusca
What are the phyla included in Ecdysozoa?
- Nematoda
- Tardigrada
- Onychophora
- Arthopoda
What are the three general characteristics of all lophotrochozoans
- Lophophore: structure used in suspension feeding
- Trochophore: Larvae with a ring of cilia used in locomotion and feeding
- Display spiral cleavage in embryo development
What is the defining characteristic in Rotifera
The presence of corona (cluster of cilia at their tail end) used for suspension feeding
Where do most rotifera live
Live in damp soils, marine and freshwater environments (Important component of plankton)
How can Rotiferas reproduce?
Usually through sexual reproduction
Can reproduce asexually through parthenogenesis
Parthenogenesis
When the unfertilized eggs via mitosis hatch into asexually produced offspring.
Characteristics of Platyhelminthes (flatworms)
- Can be free living or parasites
- Broad, flattened body; unsegmented
- Lack coelom, gas exchange structures and blood vessels
- Lack lophophore and digestive tract with only one opening for ingestion of food and elimination of wastes
Significance of the platyhelminthes (flatworms) flat body
Adaptation that provides large surface area for gas exchange
Characteristics of Annelida (Segmented Worms)
- Segmented body and a coelom
- Numerous bristle-like extensions called chaetae that extend from appendages called parapodia
What are endoparasites
Parasites that live in the tissues and organs of their hosts
What is a Mollusca (mollusk) and what are its characteristics
Phyla of Lophotrochozoans
- Foot: large muscle at the animal base used for movement
- Visceral mass: Most internal organs and external gill
- Mantle: Body wall that forms enclosure: where many species secretes calcium carbonate shells
What are Bivalves?
Species like clams, oysters, scallops, mussels that is part of the phylum Mollusca
What is the main characteristic of bivalves
A. Have a shell with two parts (valves)
1. Made of calcium carbonate
2. Hinged and closes using muscles attached to the valves
3. Protect animal from predation
B. Suspension feeders
C. Only mollusks without a radula
What are gastropods?
Species part of the Mollusca phyla that contain 70,000 marine snails, slugs, nudibranchs
Only mollusk group that transitioned from water to land
What are Chitons and its main characteristics?
Part of phyla Mollusca
- Have eight calcium carbonate plates along dorsal side that form protective shell
- Marine
- Use radula to scrape algae off rocks and move by gliding on the broad, muscular foot.
What are Cephalopods and its characteristics ?
Part of phyla Molluscs, ex octopuses and squids
- Have well-developed head
- Have foot modified to form long, muscular tentacles
- Except for nautilus, have highly reduced shells
- Most have large brains & sophisticated eyes
- Separate sexes
- Sexual reproduction and internal (male transfers spermatophore packet to female)
- Eggs develops directly into adults
- Contains Chromatophore
cells in skin that can rapidly change color for camouflage & communication
What is an Ecdysozoan and defining characteristics?
- Grow intermittently by molding
What is molting?
How ecdysozoans grow by shedding of soft cuticle or hard exoskeleton
How do lophotrochozoans grow?
They grow incrementally
What are Nematodes (roundworms)
Part of Ecdysozoans phyla
Unsegmented worms with a thick, elastic cuticle that must be molted during growth.
What are the characteristics of Nematoda?
- Free-living
- Abundant in every habitat
- Lack specialized systems for gas exchange and circulation
- Some are significant human parasites
What are Arthopoda?
Phyla apart of Ecdysozoa
- First appeared in 520mya
- At least 1 million living species
What are the characteristics of Arthopoda?
- Segmented body organized into three tagmata
- Exoskeleton made with chitin (strengthened by CaCO3 in crustaceans)
- Jointed appendages
What are myriapods?
Part of Arthopoda phyla
- Have head and long trunk with segments
- 16,000 species in terrestrial environments all over the world
Millipedes
Myriapods part of Arthopoda and are detritivores
Centipedes
Myriapods part of Arthopoda, predators that use poison
Insects
Part of phyla Arthopoda: abundant in terrestrial environments
3 tagmata
1. Head (containing pair of antenna)
2. Thorax (contains pairs of walking legs or wings)
3. Abdomen
How do insects reproduce?
Usually sexual
- Takes place through direct copulation
- Most undergo metamorphosis
What is direct copulation?
Where male inserts sperm-transfer organ into female
What is metamorphosis?
abrupt change in the form or the structure of an organism during post-embryonic development
What is Holometabolous metamorphosis?
Distinct larval stage
Characteristic of beetles, butterfies, moths, flies and wasps.
Life cycle is egg, larva, pupa, and adult.
Incomplete metamorphosis (hemimetabolous metamorphosis)
Same as complete metamorphosis but the organisms look smaller
What kind of cleavage do most Ecdysozoa have?
Radial cleavage
What kind of cleavage do most Lophotrocozoa have
Spiral cleavage
What groups of Ecdysozoa have segmented joints?
Tardigrada, Onychophora and Arthopoda
Why do crustaceans have a carapace?
Helps them protect cephalothorax
What are the three major components of mollusks
- Mantle
- Visceral mass
- Foot
What is one of the greatest evolutionary benefits of the body plan of flatworms?
Thin flat bodies allow for efficient exchange of gases and nutrients form the environment.
What are the groups of Arthropoda
Myriapods
Crustaceans
Chelicerates
What are Crustaceans and where do they live
Group of arthopoda: shrimp, lobsters, crabs, baracles, isopods, copepods
Live primarily in marine and freshwater environments
What are the structures of Crustaceans
- Segmented body with 3 tagmata
- Carapace
- 2 pair of antenna, compound eyes usually on stalks, branched appendages
What is a carapace
Plate-like section of exoskeleton that covers/protects head/thorax
Many crustaceans have this
What are chelicerates
Group of arthropoda: terrestrial creatures like sea spiders, mites, ticks, spiders scorpians
What is the structure of chelicerates
- Have 2 tagmata (cephlothorax and abdomen)
- Have 4 pairs of legs
- 1 pair of chelicerae (used for feeding, defense, movement)
- Pedipalps (diverse functions)
How spiders digest
Digestive enzymes into pray, begins externally and drinks the liquid
Mites and ticks
Chelicerate ectoparasites
Horseshoe crabs
Chelicerate omnivores
What is the definition of bilaterally symmetrical and what phylums are included.
defined as body symmetry where the body can be divided into two identical halves in only one plane.
Ex. Annelida, Platyhelminthes, Mollusca, Nematode, Chordata, echinodermata
Definition of radial symmetry and what phyla are radially symmetric
Type of symmetry in which an organism can be divided into similar halves and have multiple lines of symmetry, ex. starfish
Phyla: Cnidaria, Cternophora, and conifers
What is a lophophore
A specialized filter-feeding structure
Are all deuterostomes radial symmetric?
No only adult echinoderms are radially symmetric
Are protostomes mostly vertebrates or invertebrates?
Mostly invertebrates while deuterostomes include both vertebrates and invertebrates
