Reptile Reproduction (Lecture 7)

Question 1

reptiles as ectotherms

Answer 1

• derive thermal energy from external force to regulate body temp
• pro:great deal of flexibility of energy use through metabolism
• good at regulating thermal regulation
• move in cooler or warmer area to regulate body temp

Question 2

reptiles have lower metabolic rate

Answer 2

• dont go through insufficient metabolic

- can survive even during droughts

Question 3

life history

Answer 3

• how energy is utilize for growth, maintenance, and reproduction
• incredibly variable for animals
  ex. sea turtle, dragon

Question 4

sea turtle

Answer 4

• live 70-80 yrs.
• breed multiple times in life
• spends a lot of time in growth for sexual maturity(largest proportional cost)

Question 5

Green sea turtle

Answer 5

• female lay 4-6 clutches every 3 to 6 yr.
• larger than
• lay in clucthes of 100 to 140, 4 to 6 times in the breeding season
• 2 months for baby eggs to develop
• high mortality risk of baby turtles
• large clutches to compensate for mortality risk
• send offspring through rapid dispersal phase to get food and be away from predator
• offspring swim flat chap for two days
• get picked up by currents and stay there for 10 yrs.(go from Great Barrier re
• settle back down on reef
• fall out 2k km of coastline in QUeensland
• start to chew on sea grass and algae for 30 yrs. until reaching sexual maturity at 40 yrs.

Question 6

Green sea turtle

Answer 6

• female lay 4-6 clutches every 3 to 6 yr.
• larger than
• lay in clucthes of 100 to 140, 4 to 6 times in the breeding season
• 2 months for baby eggs to develop
• high mortality risk of baby turtles
• large clutches to compensate for mortality risk

Question 7

life history differ between species and sexes

Answer 7

• female much more costly
• 5-6 yrs of energy
• move from feeding ground to courtship (400 km)
• extremely slow long life history

Question 8

factors influencing evolution of reproductive life histories in reptiles

Answer 8

• temp has prolific effect
• diet (ecology)
• some are herbivorous but most are predators
• phylogeny(animals come from different group)
  
  • limit of design
    
    • dictate the amount of eggs laid
• not endlessly plastic or variable

Question 9

reproduction quite essential

Answer 9

• very complex
• different depending on the sex
• female determine reproductive success by the number of eggs she is carrying
• males compete and fight with other males
  
  • wound each other to prevent optimizing a female

Question 10

variation of reptiles

Answer 10

10,000 species
breeding difference
-tortoise 45 yrs
-dragons 9 months 
-only breed 2 egg 
-others 600

Question 11

within specie variation

Answer 11

• animals trying to maximize fitness to optimize investment
• decisions based on environment
• sceloporus undulatus
  
  • vary in size across the U.S.
• use energy to display life history

Question 12

constraints on reproduction by environment

Answer 12

temp
=vast variation in temp across the yr.
-reptiles in Tasmania

Question 13

temp

Answer 13

thermal timing and opportunity
hot and cold environment place very different constraints on offsprings
-prolific effect on sex determination
incubation determines sex

Question 14

reproductive cycle

Answer 14

• temp alter reproductive timing
• have to turn on reproductive tract
• reproduce through a series of event
• mature switch reproductive tract
  
  • takes month
• undergo courtship and mating (usually quick
• dictate timing and how long who have to go through the reproductive cycle

Question 15

different thermal constraints-nt

Answer 15

northern territory

• midwinter and mid-spring reproductive switch
• incubate in spring
• hatch in late spring

Question 16

different thermal constraints-sp

Answer 16

southern population
short
mid-november to late december
get ready for phase switch for winter in the fall
most reptiles inactive in the winter
emerge in late spring
end of summer is the best time for hatching

Question 17

temp

Answer 17

rate determing factor on reproduction

rate of offspring have major effect on phenotype

Question 18

egg layers(oviparious)

Answer 18

-common for reptiles

Question 19

viviparious

Answer 19

• live birth
• some reptiles can hold egg within utero
• can be simple(eggs)
• complex(placenta)
• has evolved over 100x in reptiles
• strong association with viviparity and temp
• evolved in response to cold climate

Question 20

viviparity in cold temp benefits

Answer 20

female able to regulate her and the eggs temp

Question 21

female holding on to offspring due to advantange to offspring

Answer 21

-warmer temp incubation to maximize offspring performance permanently
ex.
hot nest; fast running lizard

Question 22

temp restraint on sex determinations

Answer 22

-some reptiles have thrown away sex chromosome

non-genetic sex determination

• sex allocated to temp during incubation
• all crocodiles use it, some lizards and turtles do it, but no snakes

colder temp produce all male
warmer temp produce all female

Question 23

reptile evolve temp restraint determinants

Answer 23

better match sex with performance optimum for incubation environments