hepertology Exam 3

parental care definition

care after hatching/birth, sometime defined as any care post fertilization

examples of parental care

aerate eggs

snuggle eggs

bring water to eggs

prevent predation

benefits of parental care

higher offspring survival

benefit of both parents preforming parental care

Biparental care=best survival

cost of parental care

fewer eggs produced

lower chance of reproducing again that season

predators will eat parents and eggs

hard to hide young due to dependency on water

when do males tend to offspring

when eggs are in their territory

when do females tend to offspring

when oviposition is at a different place than mating location

aquatic eggs traits

small and abundant

why are less eggs laid in warm water then cool water

warm waters = less eggs laid, higher surface area to volume ratio to increase oxygen contact

terrestrial egg traits

larger and fewer

benefits of egg variability

different larvae size have different survival chances in different environmental conditions

prevent total loss

Wilbur-collins model (3 key points)

larvae must reach a minimum size before metamorphosis

metamorphosis must occurs before maximum size because it is no longer efficient to remain in larval stage

environmental conditions could push larval into metamorphosis before max size

what does dw/dt > g mean in the Wilbur-collins model

is the growth fast enough to make it worth staying in larval stage

when would the larval metamorph according to Wilbur-collins model

when max size is reached (w>b+c) or the conditions are poor (dw/dt < g)

plasticity in larval growth and development

Some species can have a facultative response and can shift to earlier metamorphosis if environments dry out

define facultative

occurring optionally in response to circumstances rather than by nature

define paedomorphosis

retention in adults of a derived species of characters that appeared during larval development in ancestral species

when are species more likely to stay paedomorphic

when aquatic area is more permanent and stable

amphibian reproduction

egg masses most common

direct development

retention of young in oviduct

transportation of water or young

few eggs at a time

what influences metamorphosis in the Wilbur-Collins Model

body size and growth rate

genetic sex determination

sex is determined by genes from mother or father

amphibians heterogametic gender

male or female

environmental factors that trigger breeding

rainfall

temperature

day length

the different reproductive cycles

seasonal

annually

biannually

why would a species reproduce every other year

energy limits,

migration

parental care

short breeding seasons

temperature dependent sex determination

temperature of nest controls gender

how does pollutants effect amphibians reproduction

pollutants like pesticides can alter reproduction function

modes of fertilization

internal and external

external fertilization in anurans

use amplexus to mate

male makes a basket with his feet to catch the eggs

what are the different amplexus positions

inguinal

axillary

internal fertilization

use of spermatophore

benefits of holding onto sperm

females can find better sites for laying eggs

where do females store the spermatophore

in spermathecae

example of external fertilization in caudata

hellbenders

inguinal

grab under waist and more ancestral

axillary

grab behind from legs and more derivative

example of internal fertilization in anurans

Ascaphus

internal fertilization in caecilians

copulatory organ called phallodeum is inverted during mating

hybridogenesis

genome of the female are passes unchanged from one generation to the next

kleptogenesis

females steal genomes from males of other species, but there is not a common genome that is inherited clonally

reproductive modes

Vitellogenesis

Lecithotrophy

Matrotrophy

Vitellogenesis

manufacturing of yolk in mothers liver that is transported to circulatory system and then to egg

(yolk production)

Lecithotrophy

embryos receive all their nutrition from yolk reserves within the egg

(nutrients from yolk)

Matrotrophy

embryos receive all their nutrition form their mother

(nutrients from mother)

caecilians reproductive mode

oviparity and viviparity

oviparity in caecilians

female lays eggs

dermophagy

direct development with skin feeding in caecilians

viviparity in caecilians

larvae feed on secretions of the mother

reproductiove modes in salamanders (3)

mode I

mode II

mode III

mode I

pond breeding

Mode II

stream breeding

mode III

nonaquatic eggs

salamander eggs in water

attached to logs, rocks, etc, and loosely attached in still water

salamander eggs on land

fall into water

wiggle into water

wait for flood water to reach them

viviparity in salamanders

newts

eggs are kept in the oviduct and born

reproductive modes in anurans

eggs in water, larvae in water

eggs on land, larval in water

nonaquatic larvae, direct development

birth to tadpoles

birth to young

parental care in anurans

egg attendance

transport of eggs

dig channels to water

feed unfertilized eggs to young

brood in vocal sack or stomach

downside of Direct Development and Viviparity

costly and few offspring

direct development egg traits

large size

large yolk

three types of temperature dependent patterns

pattern Ia

pattern Ib

patternII

pattern Ia

males are produced at lower temps, females at warmer

pattern Ib

females produces at cooler temps, males at warmer

pattern II

females produced at extream ends

what reptile is 100% TSD

crocs

Parthonogenesis

genetic clones of mother

Females produce offspring without fertilization

how did Parthonogenesis originate

hybridization of two or three species

example of a species that does Parthonogenesis

racerunner lizard

facultative parthenogenesis

normally sexual females can produce offspring asexually

benefits of not being tied to water

expand habitats

reduces larval stage

changes life history strategies

how does temp determine sex

hormone production (estrogen and testosterone) is affected by temp

oviparity

ancestral condition

eggs laid outside body

oviparity egg structure

mineral shell → protection

organic layer → gas exchange

water dynamics in reptile eggs

egg contains the water

water dynamics in amphibian eggs

absorb water from environment

nest stiles

buried in soil

vegetation mounds

tree cavities

attached to surface

Viviparity

eggs retained inside female

embryos develop internally

how did Viviparity evolve

in colder temps so mother could incubate embryos

parental care in turtles

rare and only in a couple species

parental care in crocs

attendance of eggs

predator avoidance care

snakes parental care

pythons with eggs

rattlesnakes with newborn

cloacal apposition

press cloacas together to transport sperm

what animals does cloacal apposition

tuatara

Associated (prenuptial) gonadal cycle

animal is fully mature before searching for a mate

hormones and mating aligne

Dissociated (postnuptial) gonadal cycle

fertilization occurs after a period of sperm storage in the reproductive tract of males, females or both

mating and fertilization are seperate

Aseasonal cycle

reproduction occurs year round

Seasonal cycle

reproduction occurs in cycles

when do animals mate guard

when searching for a mate is costly

many males and few females

amphibian mating system

mate searching

reptile mating system

search for mates

follow pheromones

atelopus mate guarding

find female and can hold on to for months

reptile mate guarding

if combat is involved mate guarding typically occurs

ex rattle snakes

lek

gathering o males on a traditional display ground

resource defense

guarding something that females want

Male persistence and allocation of resources

longer calls get more mates

longer time on lek get more mates