Section 3a - Flowering plants reproduction Flashcards
What are the petals like in insect-pollinated plants and wind-pollinated plants
Insect-Pollinated plants:
Colourful and large to attract insects
Wind-pollinated plants:
Dull and small
Is there nectar in insect-pollinated plants and/or wind-pollinated plants
Insect-Pollinated plants:
Yes, as a reward for insects
Wind-pollinated plants:
What is the scent like in insect-pollinated plants and wind-pollinated plants
Insect-Pollinated plants:
sweet smell to attract insects
Wind-pollinated plants:
No smell
What are the stigmas like in insect-pollinated plants and wind-pollinated plants
Insect-Pollinated plants:
Sticky and enclosed within the flower so contact is necessary
Wind-pollinated plants: sticks out of the plant so pollen grains blow off in the wind
What are the anthers like in insect-pollinated plants and wind-pollinated plants
Insect-Pollinated plants:
Enclosed and shielded by the petals so contact is necessary
Wind-pollinated plants:
Hang out of the plant so they can be carried by the wind the pollen grains
What are the pollen grains like in insect-pollinated plants and wind-pollinated plants
Insect-Pollinated plants:
Larger, Sticky
Wind-pollinated plants:
smaller and smoother, so can be carried in the wind
How are seeds dispersed
Wind - seeds are blown and carried by the wind to a new area
water - seed can drop into water (such as a stream and be carried to a new area)
gravity - Seeds can fall down due to gravity
animals - Animals can transport seeds (can carry them or eat and excrete them)
Explain the growth of the pollen tube followed by fertilisation and how it leads to seed and fruit formation
Step one: After pollen has landed on the stigma, it grows a pollen tube down through the style to the ovary.
Step two: The nucleus of the pollen grain travels down the pollen tube and fertilises the nucleus in the ovule.
Step three: The fertilised ovule develops into a seed
complete the sentence:
The ovule forms a _______ and the ovary in which it is found becomes a _________.
The zygote develops into an _________ with small root (_________) and shoot (_________).
The other contents of the ovule develop into a ________ for the young plant when the seed ________.
The ovule wall becomes the ________ or the ________.
The ovary wall becomes the ________; this can take many forms depending on the type of fruit
1) seed
2) fruit
3) embryo
4) radicle
5) plumule
6) food store
7) germinates
8) seed coat
9) testa
10) fruit wall
What conditions are needed for seed germination
Water - to activate enzymes and soften seed coat
Oxygen - for respiration, providing energy for growth
Suitable Temperatures - to activate enzymes
How can seeds be dispersed (5 ways)
Wind: Lightweight seeds with wings or parachutes (e.g., dandelions, sycamore) are carried by the wind.
Water: Seeds float and are dispersed by water (e.g., coconuts).
Animals:
- Internal: Seeds are eaten and excreted by animals (e.g., berries).
- External: Seeds attach to fur or feathers (e.g., burdock).
Explosive: Pods burst and scatter seeds (e.g., peas, gorse).
Gravity: Seeds fall and roll away (e.g., apples, acorns).
Why do seeds disperce
Reduce competition: To avoid competition with the parent plant.
Colonize new areas: To spread and grow in new places.
Increase survival: To escape predators and diseases.
Promote diversity: To adapt to different environments.
Explain the roles of oestrogen and progesterone in the menstrual cycle
Oestrogen:
- Produced by the ovaries.
- Stimulates the growth and repair of the uterus lining after menstruation.
- At high levels, it triggers the release of LH (luteinizing hormone), which causes ovulation (the release of an egg).
Progesterone:
- Produced by the corpus luteum after ovulation.
- Maintains the thickened uterus lining to support a fertilized egg.
- If pregnancy doesn’t occur, progesterone levels drop, causing the lining to break down, leading to menstruation.
Explain the roles of oestrogen and testosterone in developing secondary sexual characteristics
Oestrogen (in females):
- Produced by the ovaries.
- Responsible for the development of female secondary sexual characteristics, such as:
- Breast development.
- Widening of hips.
- Growth of pubic and underarm
hair.
- Start of the menstrual cycle.
Testosterone (in males):
- Produced by the testes.
- Responsible for the development of male secondary sexual characteristics, such as:
- Deepening of the voice.
- Growth of facial, pubic, and
body hair.
- Increased muscle mass.
- Growth of the penis and testes.
What are the roles of oestrogen and progesterone in the menstural cycle
FSH (Follicle-Stimulating Hormone):
- Produced by the pituitary gland.
- Stimulates the maturation of an egg in the ovary inside a structure called a follicle.
- Stimulates the ovaries to produce oestrogen.
LH (Luteinizing Hormone): - Also produced by the pituitary gland.
- Causes ovulation, which is the release of a mature egg from the ovary.
- Stimulates the remaining follicle to form the corpus luteum, which produces progesterone.
