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
0
10
20
30
40
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60
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Jan
Mar
May Ju
lSep
tNov
Jan
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May Ju
lSep Nov
Species 1
Species 2
Species 3
Species 4
Num
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f m
atin
g pe
r 10
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Months
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