Evo of the seed
When did seeds evolve?
300 million years ago
evolution of seeds - What is the relationship between pollination, gametophyte maturation, and fertilization.
the seed is pollinated, then both gametophytes mature, and then it can take up to 15 months to fertilize
What are the distinctive characteristics of gnetophytes?
have fleshy cones and only 3 genera, obvious strobili structures, showy bracts
How does the diversity of all of the photosynthetic lineages we’ve learned
about compare to one another?
What are the possible reasons for the relatively lower diversity in other
lineages?
angiosperms - the most
diatoms - the second most
everything else - tiny tiny tiny
possible reason is because everything else hasn't been studied alot so discovery left and not many adaptive traits and modifications and photosynthetic pathways
What is the correlation between albuminous seeds and seed size?
Albuminous seeds are smaller and monocots because the endosperm is used slowly, there is endosperm left and the embryo is smaller. Ex-albuminous seeds are dicots and larger because there it uses the endosperm quickly and entirely like a lil pig.
What is an ovule and how did it evolve morphologically?
Ovule is where the seeds develop and it evolved fairly quickly after true vascular tissues, and evolved to protect the nucellus
What are the processes of fertilization?
pollen grain goes through mitosis and produces 2 sperm cells one sperm fertilizes the egg and the other is aborted (no endosperm in gymnosperms)
How can you tell if a fleshy cone belongs to a gymnosperm or a is a berry
from an angiosperm?
look at it microscopically to look for bracts in cone morphology
What are the four whorls of a bisexual flower?
carpels - megasporophyll; ovary, stigma, style
stamen - microsporophyll; anther, filament
petals/corolla
sepals/calyx
Explain how flowers are modified shoots, providing definitions and
descriptions of the four whorls in your answer.
Flowers are modified shoots because they develop in the axils of bracts like axillary buds. they develop like axillary shoots.
Do seed plants produce gametangia?
yes?
What is the seed coat and what is it derived from?
from the integument and the parental sporophyte
What are some of the adaptive traits of conifers (pinophytes) that have led
to their maintenance of relatively high diversity?
can thrive in many environments and photosynthesis in the winter
What are the processes of microsporogenesis and microgametogenesis?
microsporogenesis is meiotic division to get to the pollen grain from the pollen sac
microgametogenesis is mitotic division to get the generative and tube cell from the pollen sac
Compare and contrast flowers using the following terms: perfect,
imperfect, monoecious, dioecious, complete, or incomplete
perfect - bisexual, parts of male and female, inherently monoecious
imperfect - male OR female
complete - have all whorls, always perfect
incomplete- lacking one or more whorls, can be perfect or imperfect
monecious - have all parts needed for sexual reproduction on one plant, can be perfect or imperfect
dioecious - male plants and female plants are separate, will always be imperfect
Compare and contrast the strobili of gymnosperms and those of seed-free vascular plants.
In seed free vascular plants, the strobili are under the leaves but in gymnosperms they are on the cones
What are the distinctive characteristics of cycads?
tropical showy strobili pollinated by insects
palm like
Other than wood, what are some of the ways that conifers are
economically important?
juniper makes flavoring for gin and pacific yew makes taxol that reduces cancerous cell growth
What are the processes of megasporogenesis and megagametogenesis?
megasporogenesis is the process in which megaspores are formed in the ovule; in which four megaspores are formed through meiosis and only one survives (functional megaspore), three aborted
megagametogenesis- 1 megaspore divides mitotically, 2 divide mitotically, 4 divide mitotically, remaining 8 haploid cells arranged specifically (megagametophyte)
Can you describe a flower using the terms epigynous, hypogynous,
and perigynous? Can you also correctly apply whether the ovary is
superior or inferior?
epigynous - ovary is below where whorls are fused, inferior ovary
perigynous - over is fused with whorls,
hypogynous - ovary is above where whorls are fused, superior ovary
In seed plants, what are the gametophytes? Where do you find them?
female gametophyte in the ovuliferous scale =megasporophyll
male gametophyte in the male cone = microsporophyll
What are the distinctive characteristics of Gingko?
reduced mega strobili, pollen sacs are attached to the microsporophyll's
monogeneric
What are the different parts of the embryo?
the seed coat (2N), the food supply (N), and the embryo (2N)
How does pollination and fertilization work in angiosperms, and how do they differ?
fertilization comes after pollination. The pollen grain sticks to the stigma and creates pollen tube, the generative cell travels through it and forms two sperm cells. In fertilization, one sperm cell fertilizes the egg and the other fertilizes the polar nuclei/central cell and creates the embryo and the endosperm. Fertilization takes place hours after pollination in angiosperms, and ends with endosperm. in gymnosperms, it can take 15 months for pollination to occur and does not have the endosperm. They both have the tube cell and generative cell.
What is a hypanthium and why is it ecologically important?
The hypanthium is a cup shaped enclosure around the ovary. It is ecologically important because it usually contains the nectaries to reward pollinators.