Animal life cycles: Practice Questions

In the sexual life cycle of a coral polyp, fertilised eggs float to the surface to form what structure before they descend and attach to a hard surface?

During the sexual reproduction of coral polyps, which of the following describes the correct sequence of events following the synchronised release of eggs and sperm into the water column?

During the planktonic stage of the coral life cycle, how do the larvae (planulae) typically behave before they settle to become sessile polyps?

In the life cycle of the leatherback turtle (Dermochelys coriacea), how many days do the eggs typically incubate in the nest before hatching?

After the synchronised release of eggs and sperm by coral polyps, fertilisation occurs and planktonic larvae are formed. What is the typical behavior of these larvae (planulae) in the water column?

Outline how the incubation temperature affects the offspring of a leatherback turtle.

Explain how returning to their hatching site and the 10-day egg-laying interval contribute to the reproductive success of the leatherback turtle (Dermochelys coriacea).

Outline the life history of a male leatherback turtle (Dermochelys coriacea) from the moment it successfully enters the ocean as a hatchling until it reaches adulthood.

Marine animals such as coral polyps and leatherback turtles (Dermochelys coriacea) have complex life cycles with distinct reproductive stages.
(a) Coral larvae (planulae) spend a period of time as plankton before they settle. State the type of surface they must attach to in order to successfully grow into polyps.
(b) After a female leatherback turtle has finished laying her eggs in a nest, state the immediate action she takes to protect the eggs before she departs for the sea.
(c) During a single nesting season, a female leatherback turtle will lay several batches of eggs. State the time interval (in days) typically found between these successive egg-laying events.
(d) Coral polyps often participate in a mass event where they release a huge number of eggs and sperm into the water column simultaneously. State the form of reproduction this represents.

The life cycles of the leatherback turtle and coral polyps involve specific reproductive strategies.
(a) Contrast the larval stage of a coral polyp with the hatchling stage of a leatherback turtle in terms of their movement and habitat.
(b) Explain how the environment determines the sex of leatherback turtle offspring and state how long they typically take to reach maturity.
(c) Describe the process of budding in corals and identify if this is a sexual or asexual process.