Reproduction In Flowering Plants Flashcards
Define reproduction:
- Reproduction is the biological process by which a new individual is produced from an already existing individual.
What is essential for the survival and evolution of a species?
- Genes being transferred to next generation is essential for the survival and evolution of a species.
Characteristics of Asexual Reproduction:
- one parent
- all offspring has same genetic info as parent.
- no gametes
- mitosis
- produces clones.
Characteristics of Sexual Reproduction:
- two parents
- mixture of genetic info
- gametes (sperm and ova)
- Meiosis
- Fertilisation -> gametes
List the types of Asexual Reproduction:
- binary fission
- Fragmentation
- budding
- spore formation
- Regeneration
- Vegetative reproduction
- grafting
What is binary fission as asexual reproduction?
A single parent cell divides into two daughter cells.
e.g: amoeba, bacteria
What is grafting as asexual reproduction?
- Tissue from one plant is inserted into those of another.
Pros of Asexual Reproduction:
- lots of offspring in favourable conditions.
- No energy -> no gametes
- offspring same as parent which is suited to environment
- no need to find mate or pollinator
Cons of asexual reproduction:
- could cause over Population
- no genetic variation -> adaptation is hard
- shared weak characteristics -> decreased survival.
Pros of sexual reproduction:
- gene variation-> more adaptable -> higher survival rate
- basis of evolution
- “Reshuffling of genes” -> lower chance of inheriting harmful genes
Cons of Sexual reproduction:
- fewer offspring
- high Energy cost -> flowers
- process is slower
- negative mutations can appear
- need agents (wind/insects)
What is a flower?
-what do they contain?
- A flower is an organ of sexual reproduction.
- contain both male and female gametes.
Flower likely evolved from…
Flowers likely evolved from specialised leaves.
What is the difference between pollination and fertilisation?
- pollination -> transfer of pollen from one flower to another
- fertilisation -> occurs after pollination and is the joining of male and female gametes in the ovule to form a zygote
What are the two different types of pollen transfer?
- self pollination
- cross pollination
What are the two different types of self pollination?
Type 1 -> within the same flower
Type 2 -> within different flower of same plant.
Is self-pollination considered Asexual reproduction?
No, the gametes are different to parent cell therefore it is sexual reproduction.
Why do plants avoid self-pollination?
- it is avoided as it doesn’t create much genetic variation in offspring.
What happens during pollination?
- when an anther is mature, it splits open and discharges pollen.
- the pollination is carried to the sigma by various agents.
What strategies do plants have to avoid self-pollination?
- timing -> male and female structures mature at different times.
- Morphological -> structure of organs prevent it
- Biochemical-> chemical on surface of pollen and stigma that prevents pollen tube germination on the same flower.
What is cross pollination?
- pollen is transferred from anther of a flower on one plant -> to stigma of a flower on another plant.
Fertilised ovules __ __ __ and the ovary __ __
Fertilised ovules develop into seeds and the ovary into fruit.
Describe what a fertilised ovule is:
Fertilised ovule -> seed which encloses and protects the embryo and endosperm.
What is the hardened tissue around the seed called?
-Testa (seed coat)
What does a fruit do?
A fruit protects the seed and helps with dispersal.
Embryo becomes what?
Embryo becomes a cotyledon which stores food and absorbs nutrients.
What is germination?
Germination -> when seeds absorb water.
Why are seed producing plants so successful?
- adapted for dispersal
- seeds store reserves (survive harsh conditions)
- hard testa (protects embryo)
- cotyledons -> food for developing plants
What seeds are used as food?
- grains -> starch and fibre
-legumes -> protein, low fat, fibre
-Nuts -> protein, fibre, unsaturated fats
What is a seed bank?
- A seed bank is a place where seeds are stored to preserve genetic diversity for the future.
Humans have ___ ___ __ for their use, which involved…
Humans have domesticated wild plants for their use, which involved skilful breeding to get desired traits.
How does asexual reproduction improve crops?
- asexual reproduction produces clones of parent plant
- if a mutation occurs it could produce a plant with a new superior trait
-> if that plant is reproduced by asexual means -> the offspring will get that superior trait.
How does sexual reproduction improve crops?
- sexual reproduction creates genetic Variation -> offspring would be different from parent
-> Some of the differences were beneficial
-> breeders would plant seeds from superior plants while eliminating bad seeds
-they often cross pollinate to produce new crop varieties with superior traits
Asexual reproduction and genetic engineering could be the solution to…
Asexual reproduction and genetic engineering could be the solution to the imminent food crisis.
How could asexual reproduction benefit future crop production?
- propagation is faster than from seed (due to no gametes)
- all propagated plants are considered superior quality
- large quantities of plants can be produced cheaply, easily and quickly
- using grafting, fruit trees will grow more quickly to fruit production
- Micro-propagation can produce numerous new identical clones
How does genetic engineering benefit crop production?
- Production of new variety with desired trait is achieved more quickly than conventional breeding methods
- No interspecies barriers since all organisms use the same genetic code.
What traits are biotechnologists trying to incorporate into food crops?
- flood tolerance
- resistant to diseases and herbicides
- increased tolerance to insect pests
- nutrient-content enrichment
- increased tolerance to environmental pressures
- longer shelf storage life.
How do breeders use Sexual Reproduction to improve food crops?
- crop breeders hybridise plants
- Hybrid crops are produced by cross-pollinating two inbred plants of dissimilar genotype -> resulting in genetic variation
What improvements have been made through sexual reproduction of food crops?
- more vigorous
- improved disease resistance
- earlier maturity and extended growing season
- increased yield
- quality improvements
