L5-larval biology,effect of climate on larvae Flashcards
IS there a strong link between taxonomy and reproduction?
not in marine life
one genus can have three different developmental modes
What are the two types of larvae?
Planktotrophy
Lecithotrophy
What are Lecithotrophic larvae?
larvae that don’t feed
What are Planktotrophy larvae?
larvae that feed in the plankton
What are the types of direct development?
Capsular development(eggs)
Ovoviviparity
Viviparity
How abundant is each developmental
mode?
~10% Aplanktonic
• ~40% Nonfeeding larvae
• ~50% Feeding larvae
What are the features of Direct developers?
- Internal fertilisation
- Snails, squid, sea-starts, sea cucumbers
- Few offspring, very large
- No free swimming larval stage
What are the features of Indirect developers?
- Any fertilisation
- Larval phase
- Everything but squid
- Larval phase and metamorphosis in the open
What are the features of c?
• ‘plankton feeding’
• Spend weeks to months in plankton
• Small eggs, numerous
• Thought to be ancestral, present in everything
but crinoids and cephalopods
What are the features of Lecithotrophs?
- ‘yolk feeding’
- Spend minutes to days in the plankton
- Larger, less numerous eggs
- Derived condition – very common
How does development mode affect recovery from a disaster?
Planktotrophs
then Lecithotrophs
Direct developers
How can nutrient loads affect plankton?
feed planktonic larvae which lead to being more successful which caused explosion in numbers eg. crown of thorns starfish
Which groups have larger egg size?
direct
then Lecithotrophs
then Planktotrophs
Which groups produce more larvae?
Planktotrophs
Lecithotrophs
direct
Where are aplantonic development more common?
poles
Where are Planktotrophs most common?
equator
What does More time in the plankton mean?
higher mortality
What is the primary trade off for larvae?
Fitness is a trade-off between large offspring that spend no time in plankton vs. small offspring that spend lots of time in the plankton
What should happen If food availability
decreases?
larger eggs example isthmus of panama
Where are larvae durations shortest and longest?
Larval durations are longest in the
poles, shortest in the tropics
What does higher temperature mean?
Less time in plankton
Where is average dispersal greatest and least?
Average dispersal is greatest near the south pole, high in the equator and the least in temperature regions
How well connected are australian habitats?
no well at all some of the worst in the world
What will happen as ocean heats?
more Planktotrophs
lost of loss of Aplanktonic especially in poles
species will invade towards the poles
How will larval periods change in the poles in the future?
Larval periods are predicted to get
~50% shorter in the poles!
