Studied by 212 peopleAbiotic Pollination
pollination via wind (98%) and water (2%)
Why are the plants that are abiotically pollinated usually do not have colorful or scented flowers?
Since reproductive success does not require to attract pollinators, these parts are not needed.
Biotic Pollination
transfer of pollen from one flower to another through birds, insects and other animals
Coevolution
joint evolution of two interacting species, each in response to selection imposed by the other
Petals
attract pollinators
Sepals
protect the bud as the flower develops
Carpels
female portion of the flower
Stigma
receives the pollen
Style
pathway for pollen
Ovary
structure that will become fruit
Ovule
structure that will become seed
Stamens
male portion of the flower
Anther
houses pollen grains
Filament
supports the anther
Monocot Flower
Flower parts are in multiples of three
Dicot Flowers
flower parts are in multiples of four or fives
Complete Flowers
has all parts of a flower
Incomplete Flowers
lack one or more of the parts of the flower
Perfect Flowers
has both stamens and carpels
Imperfect Flowers
missing either stamens or carpels
Staminate
A flower that only has a stamen
Carpelate
A flower that only has a carpel
Self-Pollination
Pollination of a flower by pollen from the same flower or from another flower on the same plant
Cross Pollination
Pollen grains are transferred to a flower from a different plant
Life Cycle of Angiosperms
Pollination → Fertilization → Sporophyte → Gametophyte
Alternation of Generation
life cycle of a plant alternating between a sexual phase and an asexual phase
Sporophyte generation
non-sexual stage where plants grow and develop to become flowers
Spores
reproductive cells that flowers produce
Megaspore
large spore that germinates into a female gametophyte
Microspore
small spore that germinates into a male gametophyte
Gametophyte generation
sexual stage in plants where sperm cells develop from the male gametophyte (from pollen grains) and egg cells develop from female gametophyte (embryo sac)
Sporophyte
produces flowers in angiosperms
Development of spores
Inside the flower, diploid cells undergo meiosis to produce the haploid spores
How do gametophytes become sperm and egg cells
They develop by mitosis.
Anemophily
pollination via air
Hydrophily
pollination via water
Etemophily
pollination via insects
Chiropterophily
pollination via bats
Is a sporophyte a diploid or haploid?
A sporophyte is a diploid (2n).
Is a gametophyte a haploid or diploid?
A gametophyte is a haploid (n).
How many microspores are produced in the life cycle?
Four microspores
What does each microspore become?
A pollen grain
Where do microspores develop into gametophytes?
Pollen sacs
How many megaspores are produced?
Four megaspores
How many megaspores survive?
One megaspore
What happens to the surviving megaspore?
It divides three times through mitosis.
Development of embryo sac
has a seven celled structure and a single egg cell
Chalazal end
where three antipodal cells go to, they later disintegrate
Polar Nuclei
Also known as the central cell, two haploids move in the middle and join to form a diploid cell
Micropylar End
The entry of the embryo sac two synergid cells and the egg cell go to
Pollen Grains
Each have a large and small cell. The large cell becomes a pollen tube and the small cell is a two sperm nuclei
Pollination
A pollen grain lands on the stigma so a pollen tube emerges. When it reaches the ovule, it discharges the two sperm nuclei into the embryo sac.
Double Fertilization
one sperm nucleus fertilizes the egg cells and forms the diploid zygote, a future embryo
the other fuses with the central cell to form a triploid cell, a future endosperm
After Fertilization
Ovule develops into a seed, embryo with stored food surrounded by a seed coat. The ovary grows rapidly to form the fruit that protects and disperses the seeds.
Mechanisms of seed dispersal
To colonize new areas, reduce competition, and let their seeds prosper, plants use biotic dispersal agents and abiotic agents such as water and wind
The Purpose of Sexual Reproduction in Angiosperms
creates genetically diverse offspring
anemochory
wind dispersal
hydrochory
water dispersal
ballochory
explosion dispersal
Fruit Structure
A mature ovary of the flower that protects enclosed seeds and aids in their dispersal.
What happens to the other parts of the flower?
Stamens and petals fall out, and stigma and styles wither.
Pericarp
thickened wall of the fruit that came from the ovary wall
Exocarp
outer layer of pericarp
Mesocarp
middle layer of pericarp
Endocarp
inner layer of pericarp
Simple Fruit
Fruits derived from the ovary of a single carpel or several fused carpels; are either fleshy or dry
Simple Fleshy Fruits (Examples)
Berry, Hesperidium, Pepo, Drupe, Pome
Berry
has a thin exocarp, soft fleshy mesocarp, and an endocarp enclosing one to many seeds
examples are tomatoes and grapes
Hesperidum
berry with a tough leathery rind, common in citrus fruits
Pepo
specialized berry with a tough outer rind and fleshy mesocarp and endocarp, usually members of the squash family
Drupe
thin exocarp, fleshy mesocarp, and hard stony endocarp that encases seed; examples are cherries, plums, peaches, and coconuts
Pome
fruits that develop from flower parts other than ovary, examples include apples and pears
Accessory Fruits
fruit that develops largely from other tissues than the ovary
Apple as an accessory fruit
ovary is embedded to the receptacle, where the fleshy part is, only the apple core developed from the ovary
Simple Dry Fruit
can be dehiscent or indehiscent
Dehiscent Fruits
they crack open along two seams and shed their seeds into environment when fruit is ripe
Legume
from a single ovary with two rows of ovules, they split along two lines of dehiscence after drying, examples are peas and peanuts
Capsule
has more than one carpel, examples are lily and sweet gum
Lily as a Capsule
Lily is split length wise into sections corresponding to number of carpels
Sweet Gum Fruit as a Capsule
sweet gum fruit releases winged seeds as each ovary cracks open at maturity
Follicle
develop from a single ripened ovary and split once along its lengthwise seam they need to release their seeds; examples are milkweed and columbine
Indehiscent Fruit
they retain the seed and do not crack open after ripening
Achene
a single seed that is attached to the ovary wall at only one point; examples are sunflowers, dandelions, and buckwheat
Grain
its wall is thin, transparent, and firmly attached to all points of the seed coat; examples are corn and wheat
Samara
wind borne fruit with a single seed; examples are elms, maples, and ashes
Nut
one seeded fruits with hard, stony pericarps; examples are hazelnuts, chestnuts, and acorns
Aggregate Fruit
compound fruit that comes from the joining together of several ovaries of the same flower; examples are raspberries, blackberries, and strawberries
can be either true (raspberry) or accessory (strawberry)
Multiple Fruit
comes from an inflorescence, a group of flowers tightly clustered together, when the walls of many ovaries thicken, they fuse and become one fruit; examples include pineapple and jackfruit
Seeds
matured ovule that has embryo and endosperm within a seed coat
Endosperm development
develops before embryo; the central nuclei divide into a multinucleate supercell with a milky consistency
examples of liquid endosperm is coconut milk and solid endosperm is coconut meat
Monocot endosperms
occupies bulk of kernel and is the main energy reserve for the development of the young seedling as it stores the bulk of its energy in the endosperm; has one cotyledon
Dicot Endosperms
lack endosperms upon maturity, food reserves are completely transferred to the embryo; stores food in its to cotyledon
Embryo
young plant
Endosperm
stored food for embryo
Seed Coat
encases the seed
Radicle
embryonic root
Epicotyl
embryonic shoot
Hypocotyl
junction between roots and shoots
Cotyledon
seed leaf
Embryo Development
zygote undergoes mitotic division and gives rise to terminal and basal cell
Note 
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