9.3: Osmoregulation and Energy Budgets

Question 1

Compare and contrast asexual and sexual reproduction.

Answer 1

Asexual Reproduction:
* One parent reproduces without gametes.
* Offspring are genetically identical clones.
* Common in stable environments.
* Examples: Binary fission (bacteria), budding (hydra), and fragmentation (starfish).
Sexual Reproduction:
* Two parents produce offspring through gamete fusion.
* Offspring are genetically diverse.
* Slower process, suited to changing environments.
* Examples: Mammals, flowering plants.

Question 2

Explain how fertilization strategies are determined by the environment and how they affect the level of parental care.

Answer 2

Fertilization Strategies:
1. External Fertilization:
○ Occurs in water (e.g., fish, frogs).
○ Requires water for sperm to swim to the egg.
○ Low parental care: Many eggs are produced, but survival rates are low.
2. Internal Fertilization:
○ Occurs on land (e.g., mammals, birds).
○ Fertilization happens inside the female body.
○ High parental care: Fewer offspring are produced, but survival rates are higher.|}

Environmental Influence:
* Aquatic environments favor external fertilization (abundance of water).
Terrestrial environments favor internal fertilization (protection from desiccation

Question 3

What factors determine the sex of the offspring?

Answer 3

1. Genetic Determination:
   ○ XY System (e.g., humans):
   § XX = Female.
   § XY = Male.
   ○ ZW System (e.g., birds):
   § ZW = Female.
   § ZZ = Male.
   
   2. Environmental Determination:
      ○ Temperature-Dependent Sex Determination (TSD):
      § Found in reptiles (e.g., turtles, crocodiles).
      § Temperature during embryonic development determines sex.
   3. Social Determination:
      ○ Some species (e.g., clownfish) change sex based on group dynamics.`