Vertebrata and fish Flashcards
Jawless and Jawed fish
What advantages do vertebrate have over invertebrates?
- increased complexity
- increased body size
- increased activity
- capturing food and avoiding predators
6 shared, derived characterisitcs of vertebrates?
Vertebral column
Braincase enclosing brain
2 or more sets of Hox genes
Neural crest cells
Dorsal, anal and tail fins stiffened by fin rays
Complex, circulatory system
What is the vertebral column and what does it do?
Skeletal elements enclose and protect the nerve cord
- replaces the function of the notochord
- enhances rigidity and provides muscle attachment points
- improved food capture and evasion
Cranium and head structure and functions?
Associated with pronounced cephalization
- head has brain, sense organs and cranium without jaws
- evolution of cranium allowed exapansion of nerve cord into brain and nervous system
- cranium does not completely encase brain in some vertebrates
What are neural crest cells and what do they do?
- develop along neural tube edge in vertebrate embryos
- migrate within embryo, contribute to teeth, skull bones/cartilage and diverse types of neurons
What are fins and what do they do?
membrane extensions supported by cartilaginous or bony spines
- provide balance and propulsion during swimming
- lost in tetrapods
How does the vertebrate circulatory system function?
- closed circulatory system
- heart with atleast 2 chambers
- O2 transporting hemoglobin in red blood cells; oxygenated via gills or lungs
- kidneys remove waste from blood
What is the clade of vertebrates that lacks jaws called? What animals does it comprise? (2)
Cyclostomes
hagfish, lampreys
Hagfish characteristics? cranium, vertebrae? anatomy? feeding? defense?
- cartilaginous cranium and reduced vertebrae
- flexible rod of cartilage derived from notochord
- small brain, eyes and mouth
- tooth-like keratin projections that protract and retract to pull in food
- absorb nutrients through skin
- exude fibrous slime for defense which absorbs water and swells rapidly choking predators
- bottom-dwelling scavengers
Lamprey characteristics? skeleton and vertebrae? fins? feeding?
- cartilaginous skeleton, more elaborate cranium with gill basket
- rudimentary vertebral elements
- notochord surrounded by cartilaginous segments
- no paired lateral fins; dorsal and tail fins
- suspension-feeding by burying into substrate
- parasitize fish by funnel-like sucking mouth
- rasping tongue with keratin spines
What was clade Conodonts and its characteristics?
- earliest vertebrates
- cartilaginous cranium and vertebral column
- jawless but had mineralized skeletal elements in mouth and pharynx
- defensive plates made of dermal bone on their skin
What clade makes up jawed fish and what are its shared, derived characteristics? (6)
Clade Gnathostomes
Opposing jaws
2 pairs of lateral appendaged
Mineralization of skeleton
Genome duplication
Enlarged forebrain
Lateral line system
What was the structure and purpose of opposing jaws?
- evolved from skeletal supports of pharyngeal slits
- open and close forecefully to capture and process food
- 2 pairs of branchial elements - hinged skeletal rods supporting gill arches - open and close mouth effectively to pump water over gills
- evolution of larger, wider mouths to capture larger prey
- posterior branchial elements for gas exchange (gill slits)
What can the 2 pairs of lateral appendages be?
fins or legs
What is the significance of genome duplication?
duplication of Hox genes (4 sets)
More specialization and differentiation
What is the significance of an enlarged forebrain?
Enhanced smell and vision