Unit 2 - Sex and Behaviour Flashcards
(36 cards)
What is parental care?
Any investment by the parent in an individual offspring that increase the offspring’s chance of surviving at the cost of the parents ability to invest in other offsprng
What is the benefit of parental investment?
It increase the probability of production and survival of young
What does it mean, in terms of energy, if more eggs are made?
Less energy is put into each one
Why is the investment in sperm much less than the egg?
Sperm are more numerous than eggs, eggs are larger and fewer in number
Why is there greater investment by females in gamete production?
They are larger and have a greater energy store
What happens during gestation?
The developing young are carried inside the female’s body in the uterus, providing protection and nutrients
What is internal fertilisation?
The process where the sperm nucleus fuses with the egg nucleus inside the body of the female
What is external fertilisation?
The process where the nucleus of the sperm fuses with the egg outside the body of the female
Benefits of external fertilisation
Very large number of offspring can be produced
Costs of external ferilisation
Many gametes are predated or not fertilised as there is limited parental care given to offspring and few survive
Benefits of internal fertilisation
- Increased chance of successful fertilisation
- Fewer eggs are needed
- Offspring can be retained internally for protection
Higher offspring survival rate
Cost of internal fertilisation
Male must be located which requires energy expenditure and it requires direct transfer of gametes from one partner to another
Characteristics of r-selected species
-Smaller
-Shorter generation size
-Mature quicker
-Reproduce earlier in lifetime and only once
-Produce larger number of offspring
-Limited parental care
-Most offspring don’t reach adulthood
Characteristics of K-selected species
-Larger
-Live longer
-Mature slower
-Reproduce many times in lifetime
-Produce fewer offspring
-Larger offspring
-High level of parental care
-Most offspring survive to adulthood
Where does r-selection occur?
In unstable environments where species has not reached its reproductive capacity
Where does K-selection occur?
In stable environments
What are mating systems based on?
They are based on how many males an individual has during one breeding season
What are the types of mating systems?
Polygamy (polygyny and polyandry) and monogamy
What is monogamy?
The mating of a pair of animals to the exclusion of all others
What is polygamy?
When individuals of one sex have more than one mate
What is polygyny?
One male mates exclusively with a group of females
What is polyandry?
One female mates with a number of males in the same breeding season
What do courtship rituals involve?
Signals that only members of the same species can understand
Examples of courtship rituals
- Chemicals given off
- Sounds made
- Displays to initiate mating
