Gymnosperms Flashcards
What are some characteristics of Gymnosperms?
Classified as vascular, seed producing land plants.
Photoautotrophic, eukaryotic and multicellular.
Produce naked seeds and have needles for photosynthesis.
What two types of cones do Gymnosperms produce?
Male pollen cones - contains pollen (male gametophyte)
Female ovulate cones - produces the female gametophyte (with eggs)
What are both male and female cones made of?
Scales
What do the Male scales contain and what process do they go through?
Scales contain Microsporangia (2N)
Each cell of the microsporangia undergoes meiosis to produce 4 microspores (N) They will grow into a pollen grain.
What do Female cones contain and what process do they go through?
Each scale contains 2 Megasporangia (2N)
Each cell in the Megasporangia undergoes meiosis to produce 4 cells. Only 1 survives, it is a Megaspore (N)
What process do Megaspores go through and what do they produce?
Undergoes mitosis to produce Female gametophyte.
Gametophyte produces Archegonia (N) which contains 1 egg (N) each.
What is Pollination in Gymnosperms?
An act of transferring pollen grains from the pollen cone to ovulate cone.
How do pollen grains help in pollination?
With its sperm nucleus, pollen grains are carried by the wind with the aid of air sacs or air bladders to the ovulate cone.
Pollen grains stick to the base of the ovules on the ovulate cone.
When does Fertilization occur in Gymnosperms?
When the sperm nucleus (N) combines with the egg nucleus (N) to form a zygote (2N).
The zygote will then develop into an embryo by Mitosis.
What do the pollen grains do in Fertilization?
The pollen grains germinates, forming a pollen tube that works its way through the Megasporangium. It arrives at the female gametophyte as the latter matures its archegonia.
What does the Pollen tube do?
Discharges its sperm nuclei into the archegonia.
What does the Female gametophyte become?
Becomes stored food, endosperm (N), which will feed the sporophyte after germination.
What generation are dominant and what generation is microscopic?
Sporophyte (2N) generation is dominant.
Gametophyte (N) generation is microscopic
What does Phloem do in Gymnosperms?
Transports sugars from photosynthesis, mixed with h2o (‘cell sap’) in the needles to the rest of the plant.
At maturity these are living cells.
What does Xylem do in Gymnosperms?
Transports h2o and minerals from roots to needles and stems.
Dead at maturity, known as soft wood.
What are the specialized Xylem cells?
Tracheids
What are Trachieds and what do they function as?
Small and narrow non-living cells that contain lignin in their cell walls.
They function in h2o transport but also add extra support
What are Meristems in Gymsnoperm?
The growing region of conifers (roots and branches) which grow in length, height and width.
There are 2 types of meristems.
What are the 2 types of Meristems?
Apical - creates primary growth (increase in height and length at the tips of roots and stems)
Lateral - creates secondary growth (increases in diameter in roots and stems.)
How do needles help with life on land?
reduce surface area of leaf and minimizes water loss due to evaporation.
their waxy cuticle helps prevent evaporation through outer layer of the needle.
What are Sunken stomatal pores?
allows pine needles to remain alive through rough environmental conditions and times where water isn’t as accessible.
What are Resin canals?
Small open areas in the cortex.
Secrete a turpentine substance to any insect thats tries to use the needle for protection.
What is the Ecological importance to Gymnosperms?
Are Primary Producers that provide food for animals.
Create shelter for wildlife.
Extensive roots hold down soil and prevent erosion by absorbing h2o
How is Carbon sink important in Gymnosperms
Takes in co2 during photosynthesis and utilizes it for cellular respiration.
Carbon is held in until the plant dies.
reduces amount of greenhouse gases in environment.
How is photosynthesis important in Gymnosperms?
Maintains levels of O2 in the biosphere.
The cycling of gases through plant filters the air making it cleaner and fresher.
What is Transpiration and how does it help in Gymnosperms?
The evaporation of water from plant leaves.
Plants use this to draw water up from the roots like a straw.
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