Invertebrates Flashcards
What are invertebrates?
animals that lack a backbone
95% of all animal species
What clade are all animals nested in?
Metazoan
Which protists are “represented” in porifera?
choanoflagellates
What is Porifera?
Sponges Sedentary and sessile Hermaphodites with mobile larva that settle down Asymmetric live in fresh and marina water no true tissues use choanocytes (collar cells)
What type of feeders are Porifera?
filter feeders that draw water through their bodies to collect suspended food
What do members of the clade Eumetazoa all have?
tissues
symmetry
What is Cnidaria?
sea anemones and jellies
first animals to develop true tissues
diploblastic radial symmetry with nerve net
both mobile and sessile (medusas and polyps)
some reproduce sexually and asexually (budding)
What are the two variations of Cnidarians and what is their body plan?
Medusa: mobile (jellies)
Polyp: sessile (anemone)
Gastrovascular Cavity (not a true body cavity)
One opening acts as mouth and anus, lined with tentacles
What clades are Cnidarians divided into?
Medusozoa: most or all of life-cycle (jellies)
Anthozoa: throughout life cycle (anemones/coral)
Is Cnidaria prey or predator and how?
They are heterotrophic predators
Cnidocytes: specialized cells on tentacles used in defense
Nematocyst: stinging thread that is ejected from cnidocyte, injects toxins to break down food
What do members of clade Bilateria all have?
Bilateral symmetry
triploblast
have digestive tracts
What is Lophotrochozoa?
clade constructed with extensive molecular data, with members that have widest range of body forms
What is the Platyhelmithe Phylum?
Also known as flatworms
triploblastic acoelomates
lack circulatory system
they are flattened for gas exchange via diffusion
What do Platyhelminthe have that allow them to predators or scavengers?
Ganglia: regions with concentrated nerves that act as a primitive brain
What is Cephalization?
Development of a head
What is the defining characteristic of Turbellaria?
not parasitic
What is the defining characteristic of Trematoda?
obligate parasites in molluscs and vertebrates
What is the defining characteristic of Cestoda?
All are parasitic
multiple hosts with at least one vertebrate
What is Syndermata?
Rotifers: free living animals with complex digestive system
Acanthocephalans: Parasites that have a reduced digestive system
What is Ectoprot and Brachiopod?
sessile, filter feeders that use lophophore nets to feed
What are lophophores?
ciliated structures used to capture food, gives rise to the clade’s larger name Lophotrochozoa
What are Mollusca?
soft-bodied animals usually protected by hard shell (snails)
feed using a radula to scrape/rasp
reproduce sexually
What do all Mollusca have in common in terms of body plan?
Muscular Foot: used for movement or adhesion in sessile species
Visceral Mass: region that contains internal organs
Mantle: covers the visceral mass and secretes a Hard shell
What are the four classes of molluscs?
Chitons
Gastropods
Bivalves
Cephalopods
What is the defining characteristic of Chitons?
multiple calcified plates
all marine
grazing animals that cling to rock
What is the defining characteristic of Gastropods?
torsion: twist of upper portions of the body relative to the foot
operculum: protective covering
What is the defining characteristic of Bivalves?
Two shells
sedentary and burrowing
foot evolved to dig
siphons bring water for filter feeding and gas exchange
What is the defining characteristic of Cephalopoda?
tentacles and head are derived from foot
highly evolved molluscs
What is Annelida?
bodies composed of fused segments
Longitudinal and circular muscles
closed circulatory system
What are general characteristics of Ecdysozoa?
cuticle: very tough coat and usually hard outer coat
develops into an exoskeleton
Ecdysis (Molting): shredding of the cuticle that must occur repeatedly, allows growth
What is Nematoda?
known as roundworms
diverse lifestyles
have thick but soft cuticle
sexual reproduction
pseudocoelomates with digestive canal, no closed circulatory system
longitudinal muscles
important for decomposition and nutrient cycling
How are Nematoda bad?
they are harmful parasites
trichinosis
heartworms
What are Arthropoda?
over 1 million species (mostly insects)
first seen in Cambrian explosion
Appearance of segmentation
What are general characteristic of Arthropod?
segmented with cases of Tagmosis (fusion of segments)
have jointed appendages: limbs that can bend, at high points, for diverse functions like walking and flying
cephalization and sensory organs
open circulatory system
What are arthropods completely covered in?
a chitin exoskeleton for protection, support, etc.
What are the four sub-phyla of arthropods?
Chelicerata
Myriapoda
Crustacea
Hexapoda
What are cheliceriforms?
terrestrial but some marine like horseshoe crabs
What are arachnids?
have an abdomen and a cephalothorax with six appendages like spiders
have book lungs for gas exchange
produce silk
What are millipedes?
have many legs with two pair of legs on each trunk
What are centipedes?
have fewer legs, one pair per trunk
What are crustacea?
isopods, decapods, and copepods fusion of segments highly specialized appendages two sets of antennas gas exchange
What are Hexapoda?
Class of Insects tagmosis two pairs of wings for flight three pairs of legs mainly terrestrial have tracheal system for efficient gas exchange have two forms of Metamorphosis
What is incomplete metamorphosis?
series of molts until insect reaches full size
What is complete metamorphosis?
larval and adult stage with very different forms
