| Vertebrate diversity | Fish biogeography/taxonomy | Fish morphology/physiology | Fish Ecology and Conservation | Fish Life History and Reproduction |
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vertebral column, neural crest cells.
Neural crest cells are progenitors of stem cells, and critical to coordinating the functions of cellular components. Neural crest cells migrate through the body from the nerve cord during development, and initiate the formation of neural ganglia and structures such as the jaws and skull
Name the two synapomorphies of vertebrates.
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Kingdom, phylum, class, order, family, genus, species
Name the seven levels of taxonomic classification, and give an example of each.
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Morphology - the study of the shape and structure of organisms.
Physiology - The way in which an organisms functions – how it works! The study of the function of living systems (e.g., cells, organs, organisms, etc.)
What are the definitions of morphology and physiology?
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Fundamental niche – the ‘abiotic’ niche. What kinds of environmental conditions can an organism tolerate?
Realized niche – the ‘biotic’ niche. How do biotic interactions fine-tune the fundamental niche?
What is the difference between the realized niche and the fundamental niche?
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Parthenogenesis – Asexual reproduction; growth and development of embryos occurs without fertilization
Costs: reduced genetic diversity! Benefits: don’t need two sexes to reproduce!
Define parthenogenesis. What are the advantages and disadvantages?
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notochord, hollow nerve chord, postanal tail, pharyngeal gill slits.
endostyle – longitudinal groove on the ventral wall of the pharynx that produces mucus to gather food particles
Name two of the five synapomorphies of chordates.
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Cartilaginous fishes. chimeras, ratfish, sharks, skates, rays.
cartilaginous skeletons, pelvic claspers, placoid scales, squalene-filled liver.
What are the chondrichthyans? Give an example of one, and name two synapomorphies.
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Osmoconformers – match body osmolarity to the osmolarity of surrounding environment (ONLY hagfish and elasmobranchs)
Osmoregulators – maintain, constant tightly regulated body osmolarity (most other fish)
Explain the two types of osmoregluation in fish.
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Mutualism, Commensalism, Amensalism, Competition, Predation, Parasitism
Define the six types of ecological interactions.
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Ovuliparity – external fertilization (e.g. salmon, tuna)
Oviparity – internal fertilization followed by shedding of eggs into the water. Young called ‘larvae’; carry a large, nutritious yolk sac and rapidly develop into adults. 97% of all fish Ovoviviparity – internal fertilization followed by development inside mother’s body (e.g., coelacanths, guppies). Nourishment still comes via yolk sac Viviparity – embryos develop inside female oviduct (e.g., certain shark species). Nourishment comes directly from mother (i.e., via placenta)
What are the four modes of reproduction in fish?
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540 MYA - origin of vertebrates.
Increases in ambient temperature Increase in atmospheric O2 Extinction of Pre-Cambrian taxa Evolution of eyes Ecological interactions (e.g., predator-prey)
What was the Cambrian explosion and what were several hypotheses for why it occurred?
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Ray-finned vs lobe finned fishes.
Both groups have fin rays Sarcopterygian fins have fleshy “lobes” supported by skeleton
What are the Actinopterygii, and how are they different from the Sarcopterygii?
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Most fish are ectothermic. Tuna, some sharks, swordfish are endothermic.
Compare and contrast endothermy vs. ectothermy. Give an example of each in fishes.
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Interference (direct competition for resources and mates) vs Exploitation (indirect competition for resources).
Compare and contrast the two main types of competition.
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r - intrinsic growth rate ("fast"). K - carrying capacity ("slow").
Number of offspring, age at first reproduction, longevity.
Compare and contrast r vs K selection. What do r and K represent? Name three life history traits that fall along the fast-slow continuum.
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Led to the evolution of all terrestrial vertebrates.
Lungfish and Coelacanths.
What is the significance of the class Sarcopterygii in vertebrate evolution? Name two modern day evolutionary relicts in this class.
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Teleostei
What is the largest infraclass of fishes, representing 40 orders ~450 families, 27,000 species, and 96% of all extant fish diversity?
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Rete mirabile (“wonderful net” in Latin). used by pelagic fish spending time in cold water. Heat improves muscle function, and aids foraging and migration.
Fish respiration uses counter-current exchange to maximize oxygen uptake in the gills. Oxygen-poor and oxygen-rich capillaries run counter to each other.
What is counter-current exchange? What are two physiological systems that employ this strategy in fish?
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Critical species in aquatic food webs
Nutrient transfer between terrestrial and aquatic systems Transport of nutrients, carbon, and minerals Maintaining healthy habitats (e.g., parrotfish and coral reefs Benefits to humans - food source, recreation, ecotourism
Name three ecosystem services that fish provide to aquatic ecosystems and give examples.
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Trinidad guppies. Absence of predation ->
4-5x higher densities Slower growth rates Lower birth-death rates Delayed maturity Reduced fecundity Drastic changes in male coloration - Males from low-predation upstream habitats became more brightly colored. Overfishing in Atlantic cod Faster development Reduced size at maturity
Give an example of how fish life history can evolve in response to overfishing or predation.
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Amniotic egg
Large changes in skeletal and muscular morphology Development of digits Head and neck mobility Loss of gills Loss of fins Eye placement (lateral vs. forward)
What are the selective pressures associated wth the transition from water to land, and what traits evolved in response?
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Bony fishes. Bony skeleton, swim bladder, 3 gill arches.
What are the Osteichthyes? Give an example of one, and name two synapomorphies.
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Physostomous – open connection to outside world
Can gulp air to inflate swim bladder. Primitive. Physoclistous - NO pneumatic duct and closed to outside world. Derived. Occurs in deeper dwelling fish; ~2/3 fish species are physoclistous.
What are the two different types of gas bladder in fish?
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Overfishing
Invasive fish species (peacock bass in Panama, mosquitofish in Australia, lamprey and Asian carp in US)
Name three threats facing fish populations, and give examples.
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- R-selected life-history traits: Fast growth rates, High fecundity
- Dispersal ability - Competitive ability - Lack of native predators
Name three ecological and jife history traits that are associated with invasion success.
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