Mating seasons and Plant reproduction

When does mating occur?

• Usually mating occurs just prior to fertilisation – sperm does not survive for long

• Females of some animals can store the sperm for later use – Queen Bee only mates once, and uses stored sperm to produce drones and workers

Breeding seasons

• Eggs and sperm available at the same time

• Spawning season for spawners, mating season for internal fertilisers

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MATING SEASONS

Oestrous cycle

• In humans, known as the menstrual cycle

• Mammalian females have a period of egg release

Type of cycle Examples

One oestrous cycle per year

Wolves, foxes, bears

Several cycles within a short period (triggered by day length)

Deer, sheep, goats

Several cycles within short period (triggered by spring)

Hamsters, horses

Mate then die

• Some animals only reproduce once in their life

• Short-finned eel live for many years, but only make the reproductive migration once. Eggs are shed in water, and fertilised by male, then adults die

• Chinook Salmon

Activities

Glossary: oestrous cycle, mating season, spawning season

Quick Check pg 395

Plant reproduction

Remember:

Ensuring pollen transfer

Wind pollination

Plants that rely on wind pollination:

-Have ugly flowers

-Have a sticky or feathery stigma

-Have stamens exposed to the wind

Insect pollination

- Blue or purple, as this is visible to insects

- May be shaped with a landing platform

- May have scent of food for insects (eg. Rotting meat for blowflies)

- White or yellow dots that work as reflectors

Insect must push through pollen to get to nectar

Greenhood Orchids catch gnats, which can only escape by brushing past the anther

Bird pollination

• Red, orange or yellow – attracts birds

• Usually unscented

• Nectaries at base of flower

Pollen falls on birds’ heads, and is taken to the next flower

Moving plant offspring

• Plant embryo is usually enclosed in a seed or fruit

• May be moved away from parent plant via:• Sailing on the wind• Drifting on water currents• Hitchhiking ON animals• Hitchhiking IN animals

Activities

Glossary: wind pollination, insect pollination, bird pollination

Quick Check pg 400

Biochallenge pg 401

Chapter Review Q 2, 3, 4, 6, 7, 9, 11, 12