week 9, apr 11th - 15th Flashcards
What did phylum platyhelminthes evolve
Evolved cephalization
Evolved moving in one direction to present head first to detect danger
Evolved bilateral symmetry
What is cephalization
Mass of neurons in the head that can detect stimuli
Located in ganglia
What is bilateral symmetry
Only one way to cut the animal into two equal halves
Has a head, bottom, right and left sides
What is stimuli
Change in the environment
What does acoelomate mean
Has no body cavity
Name the parts of a cross section of a planaria
Ectoderm, thin body, good surface for gas exchange by simple diffusion
Mesoderm
Endoderm
Gastrovascular cavity, incomplete digestive system, one opening
Describe phylum nematoda
Round worms
Nematodes
Mostly parasites
Describe phylum nematoda pseudocoelomates
Have a pseudocoelom
Body cavity is not completely linked with mesoderm
Describe phylum nematoda coelomates
Have a coelom
True body cavity
Completely linked with mesoderm
Describe cross section of a nematode pseudocoelomates
Pseudocoelom
Mesoderm
Ectoderm (cuticle, thick skin)
Endoderm lines the digestive tube, complete digestive system, 2 opening
digestive cavity, evolved from mouth to anus
Describe cross section of a nematode coelomates
Endoderm
Ectoderm
Mesdoderm
Coelom: true body cavity
Name the 2 types of coelomates
Protostomes
Deuterostomes
Name the protostomes phyla
Annelida
Arthropoda
Mollusca
Name the deuterostome phyla
Echinodermata
Chordata`
Describe protostomes
Spiral change
Form mouth first (blastopore)
Mesoderm origin layer blastopore
Determinate: all cells specialize at the same time
Describe deuterostomes
Radial cleavage
Blastopore becomes anus, forms anus first
Mesoderm origin at roof of archenteron
Archenteron, primitive gut (digestive tract)
Indeterminate: not all cells specialize (stem cells)
Describe radial cleavage
8 cells embryo
Mitosis
Cleavage = rapid cell division with no cellular growth (no G1)
Describe phylum Annelida
Segmented worms (earthworm, sandworm, leech)
Protostome, coelomates
Closed circulatory system, transports blood within blood vessel, using hearts creating a blood movement/pressure
Need moist skin to absorb oxygen and excrete carbon dioxide by simple diffusion
What does a sandworm have
Gills called parapodia
Ventral nerve cord
Describe the organisms in phylum arthropoda
Insects (6 legs) Arachnida (spiders, scorpions, ticks, 8 legs) Crustacea (shrimp, crab, lobster) Centipede Millipede
Describe characteristics of phylum arthropoda
Exoskeleton composed of chitin (anchors muscles) Coelomates Protostome Articulated limbs Cephalization (head) Ventral nerve cord
Name the 3 body parts of an insect
Head (sensory)
Thorax (locomotion)
Abdomen
What circulatory system does phylum arthropoda have
Open circulatory system
Describe open circulatory system of phylum arthropoda
Dorsal heart
Short blood vessels
Ostia = valves to reabsorb hemolymph
What is hemolymph in phylum arthropoda
Doesn’t transport oxygen
Is the open circulatory system of phylum arthropoda good
NO, cannot circulate “blood” without a blood pressure
State respiratory systems of phylum arthropoda
Aquatic arthropods have gills
Land/terrestrial = tracheal system (insect, millipedes, centipedes)
Name 4 parts of tracheal system (phylum arthropoda) and explain them
Spiracle = entry to respiratory system Trachea = wind pipe Airsacs = move the air/ventilate Tracheole = smaller tubes to deliver gases (O2) directly to organs
Describe phylum mollusca
Coelomate
Protostome
Spiral cleavage
Describe organisms in phylum mollusca that have an open circulatory system
Snails
Bivalves (2 shells) clams, mussels, oysters, scallops
Describe organisms in phylum mollusca that have a closed circulatory system
Squid
Octopus
Describe phylum mollusca common features
Foot for movement
Visceral mass (organs)
Mantle secretes shell (if present)
What do terrestrial molluscs have
Lungs
What do aquatic molluscs have
Gills
What are the organisms in phylum echinodermata
Sea star (star fish)
Sea urchins
Sanddollars
Sea cucumbers
Describe phylum echinodermata
Coelomates
Deuterostomes
Radial symmetry as adult
Unique water vascular system
Describe water vascular system of phylum echinodermata
Madreporite = entry to water vascular system
Tube feet = activated by the water vascular system
What does oral side of star fish have (phylum echinodermata )
Mouth
Tube feet
What does aboral side of star fish have (phylum echinodermata )
Madreporite
Dermal gills
