Ovipary, Ovovivipary and Vivipary

Question 1

What do the terms ovipary, ovovivipary and vivipary mean?

Answer 1

• terms that describe the moment at which the future offspring separates from a parent

Question 2

What do the ovipary, ovovivipary and vivipary strategies indicate?

Answer 2

• where the embryos develop
• how the embryo and foetus are nourished

Question 3

What happens in oviparous animals?

Answer 3

• the eggs develop outside of the parent
• may be fertilised externally or internally

Question 4

What food do developing oviparous embryos receive?

Answer 4

• egg yolk

Question 5

How does oviparity in aquatic environments maximise reproduction?

Answer 5

• the eggs are released into the water and fertilised externally
• enormous numbers of eggs are needed as the eggs and developing embryos are very vulnerable to predation
• the vast numbers ensure the survival of the species
• but require a high-energy input from the female
• this is offset by less energy being needed for yolk production and parental care

Question 6

How does oviparity in land environments maximise reproduction?

Answer 6

• very few eggs are produced, saving energy
• a shell protects the developing embryo from predators, pathogens, physical damage and dehydration

Question 7

What is the conserved energy used for in oviparous land animals?

Answer 7

• to produce eggs with more food (nutrient-rich yolk and protein-rich albumen) which allows the animal to be more fully formed at hatching
• to protect and incubate the eggs before hatching
• parental care for the young

Question 8

What happens in ovoviviparous animals?

Answer 8

• the eggs that are fertilised internally are kept inside the female body until they hatch
• therefore, offspring are born ‘live’

Question 9

Where do ovoviviparous embryos get food from?

Answer 9

• from the large amount of yolk in the egg

Question 10

Are ovoviviparous embryos dependent on the mother?

Answer 10

• no, except for physical protection and gaseous exchange

Question 11

How does ovoviviparity maximise reproduction?

Answer 11

• fewer eggs are produced so the mother’s energy expenditure is less
• developing embryo is much less vulnerable to predation and cold temperatures
• the young are born fully developed so are able to get their own food and escape predators more easily

Question 12

What happens in viviparous animals?

Answer 12

• fertilisation is internal and the eggs do not have a shell

Question 13

How do viviparous embryos obtain nourishment?

Answer 13

• from the mother
• usually through a placenta

Question 14

How does viviparity maximise reproduction?

Answer 14

The reduced number of eggs means more energy is available to:
- nourish and protect the embryo and foetus
- provide parental care after the young are born
- in this way, the chances of offspring surviving and reaching reproductive age are greatly increased