Lecture 11 Flashcards
Why are Angiosperms considered “deceptive beauties”?
Because they lure insects with nectar; both the plant and the pollinators benefit from this.
What is something that is common between plants and other species?
Mutualistic Symbioses
In what ways can Angiosperms reproduce?
Sexually or asexually.
Which group of plants are the most important group of plants in terrestrial ecosystems and in agriculture?
Angiosperms
What are plant lifecycles characterized by?
Alternation of generations between a multicellular haploid generation and a multicellular diploid generation.
Diploid sporophytes produce spores (n) by meiosis; these then grow into haploid gametophtyes.
What do gametophtyes produce? How do they do so?
They produce haploid gametes by mitosis; fertilization of gametes produces a sporophyte.
Which of the generations in dominant in Angiosperms?
Sporophyte, the large plant that we see.
What can be said about the gametophtyes in angiosperms?
They are reduced in size and are dependent on the sporophytes for nutrients.
What does it mean that the Angiosperm Life Cycle is characterized by 3 F’s?
They are characterized by flowers, fruit, and double fertilization.
Where does pollen develop from?
Microspores within the microsporangia, or pollen sacs of anthers.
What process do microspores go under to produce cells?
They undergo MITOSIS to produce 2 cells: the generative and tube cell.
What does a pollen grain consist of?
A two-celled male gametophyte and the spore wall.
What occurs when pollination is successful?
A pollen grain procures a pollen tube that grows down into the ovary and discharges two sperm cells near the embryo sac.
Where does the female gametophyte develop in angiosperms and what is another name for it?
The embryo sac, or the female gametophyte, develops within the ovules.
What is the megasporangium surrounded by?
Within an ovule, two integumentary surround a megasporangium.
How are megaspores produced?
One cell in the megasporangium undergoes MEIOSIS, producing four megaspores, only ONE of which survive.
What happens after the production of megaspores in Angiosperms?
The megaspore divides, producing a large cell with 8 nuclei. The cell is then partitioned into a multicellular female gametophyte, the embryo sac.
In ANGIOSPERMS, what is pollination?
The transfer of pollen from the anther to a stigma.
Through what methods can pollination occur?
Wind-Water-Animals.
Which type of pollination tends to release large amounts of pollen?
Wind-Pollinated Species.
Define Coevolution
The evolution of interacting species in response to changes in each other.
Many _____ have coevolved with specific _____.
Flowering Plants-Pollinators
What do the shapes and sizes of flowers often correspond to?
The pollen transporting parts of their animal pollinators.
What does double fertilization result from?
The discharge of two sperm from the pollen tube into the embryo sac; one sperm fertilizes the egg, and the other combines with the polar nucleus, giving rise to the triploid food-storing endosperm.
