EBIO 4050 Exam 4 Study Guide Question Answers

EBIO 4050 Exam 4 Study Guide Question Answers - WIP as semester progresses

List three forms of environmental sex determination in fishes

Stress, social, temperature

Provide a generalization about master sex determining genes in fishes

They are highly variable and not conserved across different species

List two types of chromosomal sex determination systems in fishes

XX/XY and ZZ/ZW

Describe sex determination in wild and laboratory zebrafish

In wild they use ZZ/ZW where in lab they have no clear sex chromosomes

Provide an example of closely-related fish species with different sex determination mechanisms

Lake Malawi Cichlids

Define the gonochorism sex system and give an example

Individuals reproduce as one sex throughout their lifetime (male or female); zebrafish

Define the protogyny sex system and give an example

Female-first sequential hermaphrodisms: individuals first reproduce as females, change sex once with increasing size/age and then reproduce as males; parrotfish

Define the protandry sex system and give an example

Male-first sequential hermaphrodisms: individuals first reproduce as males, change sex once with increasing size/age and then reproduce as females; clownfish

Define the bidirectional hermaphroditism sex system and give an example

Individuals can change sex more than once in either direction throughout their lifespan; coral goby

Define the simultaneous hermaphroditism sex system and give an example

Individuals produce gametes of both sexes at the same time or in a short period of time; chalk bass

Describe a mating system in fishes that would favor the evolution of protandry

Monogamy, single mate

Describe a mating system in fishes that would favor the evolution of protogyny

Harem, male protects many females

What is unique about the mating system of the Mangrove Killifish (Kryptolebias marmoratus)?

Self fertilization

Briefly describe how you would produce a GloFish if you weren’t worried about patent infringement

Enhancer + promoter + cDNA of fluorescent protein gene injected into a fertilized fish egg

List two components of the DNA construct used to produce AquAdvantage salmon

Chinook salmon growth hormone gene and ocean pout antifreeze protein gene

List two precautions that are taken to prevent AquAdvantage salmon from escaping and interbreeding with wild Atlantic Salmon (Salmo salar)

All triploid so sterile and raised in areas where they would not naturally survive

In what sense are there “so few fish in the sea.”

Much more fish in freshwater per capita than saltwater

Provide two potential explanations for why there are so few fish in the sea

Lack of nutrients and overfishing of late maturing fish removing rebound ability

What is the single best predictor of marine fish species richness?

Closeness to the equator due to temperature

Provide two potential explanations for the species richness of the “Coral Triangle.”

Many, relatively old colonizations of the region, center-of-origin, and many will migrate from different oceans here, center-of-accumulation

Describe the relationship between species richness and speciation rate for marine fishes

An inverse relationship with richness near the equator

Distinguish among primary, secondary, and peripheral division freshwater fishes and give an example of a family included in each category

Primary: strictly intolerant of salt water; Cyprinidae
Secondary: able to occasionally cross narrow sea barriers; Fundulidae
Peripheral: predominantly marine families; Poeciliidae

List the six freshwater zoogeographic regions in order from greatest to least number of included species

Neotropical, Ethiopian, Oriental, Nearctic, Palearctic, and Australian

In what region of North America is the greatest number of freshwater fish species located?

Southeast

List the three ichthyological provinces in the state of Colorado

Colorado River Basin, Missouri River Basin, and Rio Grande Basin

What is a “continentally outstanding phenomenon” present in the Colorado Ecoregion?

The unique assemblage of large-bodied, highly specialized minnows and suckers adapted to extreme river conditions

Identify a species of fish found in all three ichthyological provinces in the state of Colorado

Bluehead sucker

Distinguish among troglobites, troglophiles, and trogloxenes

Troglobite - found in caves and display convergent phenotypes, such as loss of eyes and pigmentation
Troglophile - can complete its life cycle in caves but may also do so outside of caves
Trogoloxene - habitually enters caves but must return periodically outside for certain living requirements (bats)

Provide three examples of common troglomorphisms

Reduced or lost eyes, pigment, and aggression

Provide at least one line of evidence that reduction of eyes and pigment in the blind cavefish Astyanax mexicanus occurred by independent mechanisms in different lineages

Phylogenetic tree by genome sequencing shows no phylogenetic group of fish without eyes

Briefly describe three different models for how natural selection or genetic drift may have led to the frequent reduction of eyes in troglobitic fishes

Direct selection for reduced eyes, selection for a feature which is linked to eye reduction through pleiotropic genes, and relaxation of selection allows accumulation of neutral mutations that reduce eyes

Briefly describe three different studies in Astyanax mexicanus that provide support for one or more of the models you described in question (Briefly describe three different models for how natural selection or genetic drift may have led to the frequent reduction of eyes in troglobitic fishes)

Increase of shh gene for more tastebuds reduces eyes. If you reduce eye size, you increase neuromasts in eye. Visual system takes up to 15% of resting metabolism.

List three examples of speculating foragers along with their specific behaviors that fall in this category

Logperch flips rocks, hogfish dig through rubble, and wrass flip debris

List an example of passive search by benthic predators and one example of passive search by predators in the water column

Stargazer barried in substrate and gar lie motionless in the water column

List two examples of predators that engage in cursorial pursuit

Marlin and tuna

List three lurking (fast start) predators

Gars, pikes, and barracudas

Define thanatosis and give an example in fishes

Playing dead, hognose brochis

Briefly describe two examples of fishes that immobilize prey before capture

Electric eel and stargazers stun prey

List two examples of fishes that are detritivores and two that are herbivores

Suckers and mullets are detritivores, sturgeon and parrotfishes are herbivores

Define protective resemblance and give three examples from fishes

Trying to look like something uninteresting:
Leafy sea dragon resembles drifting kelp
Sargassum fish resembles sargassum weed
Stonefish is identical to rock or coral rubble

Distinguish between Batesian and Müllerian mimicry. Provide one example of each in fishes

Batesian: resembles unpalatable species; snake eels
Mullerian: unpalatable species mutually resemble each other; toadfish

List two examples of brood hiding fishes

Convict cichlid and armored catfish

Briefly describe two examples of nest building guarders in fishes

Substratum choosers: clean off suitable area of bottom
Nest spawners: construct some sort of structure, cavity or pit in which eggs are laid, fertilized, and embryos defended

List two groups of fishes in which mouth brooding may be found

Cichlids and ariid catfishes

List and define three types of polygyny in fishes and give an example of each

Resource defense: male holds territory with resources like rare rocks; sunfish

Female defense: male directly guards females; elephant nose fish

Lek: males display at communal sites, females choose; guppies

List one example of polyandry and one example of monogamy in fishes

Polyandry: seahorse, monogamy: french anglefish

Briefly describe parental and parasitic reproductive tactics in the bluegill and in salmon. Include in these descriptions the proper use of the terms “parental”, “sneaker”, “satellite”, “jack”, and “hooknose”.

Bluegill: Parental male builds/guards nest. Parasitic Sneaker males dart in and release sperm and parasitic Satellite males mimic females to sneak near nests.
Salmon: Parasitic Jacks are small early-maturing male that sneak fertilizations. Parental Hooknoses are large male that migrate and compete for females.

Briefly describe hybridogenesis in fishes and give an example

Hybrid females reproduce sexually but only one parent's genes passed on; Poeciliopsis hybrids

Distinguish between iteroparity and semelparity and give an example in fishes of the latter type of reproduction.

Iteroparity: breeds multiple times
Semelparity: breeds once then dies; Pacific salmon

 Briefly describe gynogenesis in fishes and give an example

Females reproduce using sperm only to trigger development; Amazon molly

What is a common feature of virtually all of the fishes considered extinct?

Freshwater

What three families of fishes contain the largest number of extinct species?

Cyprinidae, leuciscidae, and salmonidae

What are two correlates of high extinction rates in fishes according to Helfman (2007)

All freshwater and small

What is the strongest driver of freshwater fish extinctions according to Vardakis et al. (2025)?

Natural system modifications

List the three greatest threats to freshwater fish species according to Arthington et al. (2016)

Invasive species, climate change, and habitat loss

List the two greatest threats to marine fish species according to Arthington et al. (2016)

Exploitation and habitat loss

List four of the fish species considered to be among the 100 “world’s worst invasive species” by the IUCN

Common carp, rainbow trout, mosquitofish, and walking catfish

List two biogeographical realms (freshwater zoogeographic regions) in which the majority of river basins are NOT colonized by non-native fishes

Neotropical and Ethiopian