Exam #1 Flashcards
Vertebrate Evolution, Living in Water, Chondrichthyes, Bony Fish
Extinct
no longer living.
Extant
still living.
What is the relationship between mass extinction and species diversity?
short-term & long-term
- short-term, mass extinctions have a direct negative effect on diversity as a large number of species are wiped out during these events.
- long-term, mass extinctions can lead to an increase in diversity as surviving species rapidly evolve and fill newly available ecological niches.
What is the name of the period and era when vertebrates first appeared?
Cambrian Period, Paleozoic Era.
Monophyletic
identified ancestors and all of its descendants.
Paraphyletic
identified ancestors and some of its descendants.
Polyphyletic
Descendants with shared characteristics but no known common ancestor.
Outgroup
a group that shares certain similarities to the main group you are speaking of, but just different enough that they sit outside the group.
Shared Derived Characters
characteristics only found in the descendants.
first appearance
Shared Ancestral Characters
characteristics found in the ancestor and its decendants.
after first appearance
Homologous
a trait that is the same in both the ancestor and its descendants.
ex. human limb & cat limb
Analagous
a trait with the same components but different functions.
usually evolved independently.
ex. wing & flipper
Convergent Evolution
a characteristic with the same functional trait in distant groups.
ex. power of flight in birds and insects.
Parallel Evolution
a characteristic with the same functional trait in closely related groups.
ex. extinct wooly mammoth and extant modern elephant, shared a common ancestor.
Is evolution random or direct?
random.
if it was direct, we would have a perfect organism.
What are the names of the Periods where important vertebrate events took place?
- Cambrian Period → first vertebrate fish.
- Silurian Period → distinct head, sensory input, first complex brains.
- Devonian Period → jaws w/ teeth, limbs, land dwelling.
What are unique characteristics seen in chordates and/or vertebrates that were not seen in any other animal in early history?
Chordates:
- dorsal hollow nerve cord
- notochord
- pharyngeal gill slits or endostyle
- muscular, post-anal tail
Vertebrates:
- backbone
Skeletal System
functions in support, movement, protection, and storage of calcium and phosphates.
What are the 2 parts of the Skeletal System?
- axial = skull, vertebrae.
- appendicular = appendages (start at the gnathostomes!).
What 3 components are the cranial skeleton made of?
- dermatocranium = protects brain, anchors teeth, and provides attatchement sites for muscles.
- chondrocranium = forms from neural crest; protects the brain, nose, and inner ear.
- splanchnocranium = forms from neural crest; upper/lower jaw, gill arch skeleton, functions in feeding and respiration.
What mineralized tissues are found in teeth?
dentine, enamel, enameloid, and cementum.
enamel & dentine = fish scales, armor in early verts.
enameloid = fish scales.
cementum = mammalian teeth (fix into sockets).
Cartillage
- flexible connective tissue.
- internal skeleton of chondrichthyans.
What are the different types of bone?
dermal = forms in skin w/o cartillagenous precursor; skull bone. → ostracoderms
endochondrial = has cartillagenous precursor; internal skeleton.
perichondrial = has aspects of the other two.
first seen in early tetrapods and bony fish.
Muscular System
functions in movement either of the body (voluntary) or the organs within (involuntary).
What are the 3 muscle types?
cardiac = combination of smooth and striated; heart.
skeletal/striated = voluntary movement.
smooth = involuntary movement.
What are the 3 parts of the vertebrate brain?
forebrain, midbrain, and hindbrain.
expansion & modification of the dorsal nerve cord produced these functionally distinct regions.
Forebrain
recieves and intigrates sensory information from the nose, eyes, and ears.
Midbrain
coordinates reflex responses to sight and sound.
Hindbrain
reflex control of respiration, circulation, and other basic tasts.
Nervous System
regulates and integrates information from both the external and internal environments to control motor, sensory, and automatic body functions, as well as higher functions of the brain, such as cognition.
What is the basic unit of the nervous system and what do they do?
neurons; use electrical and chemical signals to send information.
Nerve
collection of axons.
axon = long extentions of neurons.
Myelin Sheath
a fatty insulating coat that surrounds the axon and increases conduction velocity of the nerve impulse.
inverts don’t have this, they increase the diameter of the axon, therefore less nerves.
HOX Genes
lay out basic body forms of many animals.
head-to-tail organization
How do HOX Genes bring about these body forms? What are the key factors?
clusters of transcription factors initiate expression of other genes that bring about these effects.
- concentration
- location
- timing
- target gene specificity
mosty body plan charachteristics happened in invertebrates first (excluding the backbone).
What are the main HOX Gene duplications we talk about?
- 2 clusters → craniation (Craniata)
- 4 clusters → jaws & paired appendages (Gnathostomes)
Who was the first group to have bone, jaws, and tooth-like elements?
Gnathostomes
conodonts had tooth-like elements, but NOT TEETH!
How do Ostracoderms differ from other Agnathans?
first appearance of bone (dermal), had an external head shield/bony armor.
Agnathans
“jawless fish.”
What are the main differences between hagfish (Myxiniformes) and lamprey (Petromyzontiformes)?
Hagfish:
- DO NOT HAVE TRUE VERTEBRAE!
- scavengers (have more complex digestive system).
Lamprey:
- TRUE VERTEBRAE!
- parasitic, drink blood (less complex digestive system).
- return to freshwater to lay eggs (ammoecetes).
What type of ventillation is used by lampreys, chondrichtheyes, and bony fish?
lampreys = gill muscle contractions
chondrichtheyes = most use ram ventilation (swim w/ mouth open to force water over their gills, requires constant swimming).
bony fish = buccal pumping (water drawn through mouth, passes over gills, and exits through operculum).
all contain gill slits.
Where do jaws originate from?
the first and second gill arches.
What are the differences in physical properties between water and air?
Water:
- 800x denser than air
- 55x more viscous than air
- incredibly thermally stable (avg. T is avg. depth of ocean).
- 25x faster heat conductivity than air.
- 35x as much oxygen in water than air (lower in water).
What are the advantages and disadvantages to living in water?
Advantages:
- density of water counteracts gravity.
- relatively stable environment.
Disadvantages:
- water always moving, cant just stop.
Counter-Current Exchange System
the flow of water and blood move in opposite directions over the respiratory surfaces which maximizes the diffusion area.
same dirrection would reach equillibrium and would not be able to exchange anymore.
What is the difference between circulation through fish and other vertebrates?
fish have a single circulatory loop (blood passes through the heart once per complete circuit of the body) and have 2 chambers in the heart.
other vertebrates have a double circulatory loop (passes twice) and have 4 chambers on the heart.
What are the different types of internal gills?
- pouched gills → agnathans
- septal gills → chondrichthyes
- opercular gills → osteichthyes
What are the 2 types of gas bladders?
- physostomous = attatched by a pneumatic duct; gulp air at the surface to fill.
- physoclistous = completely seperate from the digestive tract; fill with countercurrent exchange system to force air inside (can exist in deep water).
What are the main anatomical parts of the gill?
- operculum = a bony flap that protects the gills.
- gill arch = support of gills.
- gill fillaments = enables gas exchange.
- secondary lamellae =has exchange.
What are the derived characteristics of Chondricthyes?
- cartilagenous skeleton
- jaws
- paired appendages (graspers)
- placoid scales
- heterocercal tail
- subtonal mouth (moves under snout and further back)
Describe the major differences between the different groups of chondrichthyes:
- Euchondrocephaali (chimaeras/ratfishes) →seperate R & L opercular openings.
- elasmobranchii (sharks, rays, skates) → gills located on plates of tissue, creating multiple gill openings (5-7).
Describe the major differences between the different groups of elasmobranchs:
neoselachii
- sharks (selachii) →torpedo shaped, 5-7 pairs of gill openings, pectoral fins not fused with the head.
- skates & rays (batomorphi) → DV flattened, 5 pairs of gill opening, pectoral fins fused with head.
modern day
What is the first and second radiation of Chondrichthyes?
progressing towarss a more complicated and predatory body plan.
What is the third radiation of chondricthyes?
- subtonal mouth
- heterocircle tail
- placoid scales → reduces drag, helps w/ osmoregulation.
- hydrostatic jaw suspension
- snouts w/ lots of sensory input → find things.
What are the different senses chondricthyes use in prey capture?
- sensing → pores along the mouth and nose
- smelling → detect blood concentration.
- seeing → move side to side to see objects in front, reflective layer to see in dim light.
- hearing → semicircular canals help with balance and keen hearing.
- skin → protective layer
- lateral lne → senses environment
Do sharks have maternal investment?
in most cases, no.
Viviparity
birht live young.
Oviparity
lay eggs.
oviviparity
eggs are retained inside the body, hatch inside, and feed on yolk before being birthed.
How do we determine ecological groupings/roles?
depends on where you find them and what they eat.
