Reproduction & Life Histories Flashcards
aspects of reproduction
- gender systems
- sexual characteristics
- mating systems
- spawning behaviors
semelparous reproduction
- typically diadromous
- all your eggs in one basket
diadromous
migrate between marine or freshwater
pros/cons to semelparous reproduction
great reproductive output but subject to environmental variance
examples of semelparous fish
- Salmon
- Lamprey
- Eels
iteroparous reproduction
- most fish
- evens out variance in reproductive success
pros/ cons to iteroparous reproduction
have a resonable output but it is spread over time
gonochoristic gender systems
- chromosomal
- 98% of fishes
- male heterogametic (XY)
- female heterogametic (ZW)
heterophroditism gender systems
- simultaneous
- protandrous or protogynous
protandrous
first male and then changes to female
protogynous
- most common
- first female and then changes to male
unisexuality
- gynogenesis
- hybridogenesis
gynogenesis
- reduced genetic variability
- no males needed
hybridogenesis
hybrid passes only genome that matches the one it backcrosses to
examples of simultaneous hermaphrodites
- killifish
- hamlets
examples of protandrous sequential hermaphrodites
Pomacentridae
examples of protogynous sequential hermaphrodites
17 marine families
example of clown anemone fishes
- groups of 2 large & several smaller individuals
- largest is active female, next largest active male, remainder are inactive males
another name for unisexuality
parthenogenesis
gynogenesis in unisexuality
sperm activates development of egg but no genetic transfer occurs
hybridogenesis in unisexuality
fertilization occurs & true hybrids are formed
subsequent miosis
male chromosomes are lost
primary sexual characteristics
features involved with copulation or parental care
examples of primary sexual characteristics
- poeciliidae pelvic fins form gonopodium
- male sharks & skates have claspers
- male seahorses have pouch for parental care
secondary sexual characteristics
- exclusive or differential
- appear or maturation
- associated with breeding season
- enhances fitness but not survival
characteristics of sexual dimorphism
- body size, fins
- color
- swelling and growth of body features
- tubercles
- body ornament
- electric signals
tubercles
bumps of keratinized epithelium
example of fish with mass release of eggs
- sticklebacks
- livebearers
- herrings
2 types of polygamy
- polygyny
- polyandry
polygyny
male animal has more than one female mate
example of polygyny fish
perch
polyandry
female animal has more than one male mate
example of polyandry fish
clownfish
monogamy
fish pair up together
examples of monogamy fish
butterfly fish
non-guarder spawning behaviors
broadcast spawners
broadcast spawners
- widely dispersed
- buoyant
- high fecundity & mortality
- mass spawning groups
benthic spawners spawning behaviors
demersal or adhesive eggs
brood hiders spawning behaviors
- benthic
- crevice spawners
- invertebrates
- annual fishes
guarders spawning behaviors
- substrate choosers
- nest spawners
- froth nests
- cavity nesters
- anemone nesters
substrate choosers
male cleans substrate before enticing female
nest spawners
- cavity or pit
- eggs laid, inseminated, & guarded
froth nests
- bubble nest for eggs
- eggs developed in air bubbles
bearers spawning behaviors
- externally hold eggs on outside of bodies
- internal fertilization is female only with a small number of young
ovovivparity
- eggs without supplemental nutrition
- only yolk is available but eggs are retained by the female for some time
viviparity
young get supplemental nutrition during development
viviparity in chondrichthyes
- few large young
- uterine milk secretions taken up by a stalk of the yolk sac analogous to umbilical cord
- oophagy
- embryonic cannibalization
- placental viviparity
viviparity in poeciliidae
- vascularized pericaridal tissue loops around neck of embryo & maintains contact with ovarian wall
- other species feed on yolk sacs
viviparity in goodeidae
- Trophotaenia
- nutrition
- respiration
trophotaenia
outgrowth of intestine that maintains contact with the ovarian wall
alternative life histories in anglerfish
parasitic males
cuckoldry
early maturation of males, big testes in small fish
aspects of life histories
- fecundity
- fertilization
- early life history
- age & growth
- senescence
fecundity
- egg size
- parental care
- body size
fertilization
female provides egg with yolk & materials that drive early development & proliferation
animal pole
top portion that becomes embryo
vegetative pole
where yolk is concentrated
external fertilization
gametes viable for a short time
internal fertilization
sperm storage
early life history
- embryonic period
- larval period
embryonic period
development entirely dependent on nutrition provided by mother
larval period
- hatches from egg
- ability to capture food
- swim-up stage
indirect development
larval stage with distinct metamorphosis
direct development
larval stage brief or not definable
age & growth
- indeterminate
- size classes
- scales
- otoliths
senescent period
- growth has stopped
- gonads degenerate
why are fish so long-lived?
- reduced mortality = delayed senescence
- intermediate growth = potential for increased fecundity with age = delayed senescence