Parental Care Flashcards
Define Parental Care
a behavioural and evolutionary strategy adopted by some animals, involving a parental investment being made to the evolutionary fitness of offspring
What are the costs to parental care?
- Less quantity of offspring
- Lots of energy expenditure
- Lots of food expenditure
- Require protection
What are some benefits to parental care?
- Higher rates of offspring survival = pass on offspring
Which animal groups have higher rates of parental care?
Mammals (k selected species)
Birds
Which animals groups have lower rates of parental care
Amphibians
Fish (r selected species)
Reptiles
What is parental care like in fishes
- Virtually no parental care
- High fecundity (large numbers of young produced, lower survival rate)
- Resources widely spread in environment
What is the trade off for parental care
Chose between investing time in young so they survive, or spawning again – looking at best success rate, best fitness rate
Define fecundity
The ability to produce an abundance of offspring (fertility)
Reproductive potential
What requires more parental investment energy; large or small eggs?
Large eggs = more energy needed
What kinds of fish have well-developed large eggs
Freshwater bony fish +
Sharks, skates, rays (elasmobranchs)
What type of fish have small, relatively under developed eggs?
Most salt water bony fish
What types of eggs are planktonic?
Small, relatively under developed eggs
What types of eggs are lecithotrophic?
Intermediate eggs
Define lecithotrophic
A form of development in which the embryo receives no nutrition other than the yolk originally contained within its egg
Define Planktonic
The small or microscopic organisms that drift or swim weakly in a body of water, including bacteria, diatoms, jellyfish, and various larvae
What are 3 costs to parental care in birds?
May reduce parent’s survival (lower resources)
Energy input is high
Brood size can affect quality of parental care
Greater risk of predation
Prevents mating again (Hamilton’s rule)
What are 3 benefits to parental care in birds?
Increases survival rate of young
Parents provide protection against predators
Parents provide thermal heat
Parents provide food
Antibodies in egg yolk can provide immune support
Maternal micronutrients in the egg can influence sexual ornamentations in adulthood (Zebra finches)
What is parental care like in barnacles
No parental care
Eggs and sperm are shed into water
Larvae drift away to find new locations
What happens when Steller’s Jays calls were played near North American Robins’ nests?
Robins reduced activity away from nests (stayed closer to nest)
Shows that long-lived species are not willing to sacrifice nests (despite science predicting they will chose to just reproduce again)
What happens when tapes of Sharp-Shinned Hawks are played near the South American Argentinian Rufous-Bellied Thrush?
Adult birds reduced time spent at the nest, stayed away.
Shows the threat of the hawk made the Thrush less wiling to risk self for current brood (despite being a short-lived species)
what % of DNA is shared with an individual, parent and sibling?
o Parents share 50% of genes with offspring
o Offspring 100% DNA itself
o 50% of genes shared with siblings
What is Hamilton’s Rule
Hamilton’s rule is a kin selection theory that predicts that social behaviour evolves under specific combinations of relatedness, benefit and cost.
What is weaning
The process of a parent withholding food from young because they cannot provide enough calories for them and they must begin to feed themselves
What is parent-offspring conflict
parents and offspring should disagree over the amount of parental resources invested in the offspring so that offspring should always demand more than parents are willing to invest.
