Chapter 30, Seed Plants Flashcards
(email) What are the three parts of a seed?
Embryo, nutrients, seed coat
(email)Why is it said that a seed contains three generations?
The embryo is a grandchild sporophyte (2n), food source is the parent gametophyte (n), the coat is the sporophyte grandparent (2n)
(email) What are some advantages of having seeds?
They can survive better than spores, they can be transported long distances, they can go dormant until conditions are good
(email) Name the four traits common to all seed plants (other than seeds)
Reduced gametophytes, heterospory, ovules, and pollen
What are the two types of sporangia of seed plants and what do they produce?
Megasporangia produce megaspores that develop into female gametophytes
Microsporangia produce microspores that develop into male gametophytes
What are the three parts of an ovule?
Consists of a megasporangium, a megaspore, and one or more integuments that envelops and protects the ovule
Define pollination
The transfer of pollen to the part of a seed plant containing the ovules
What is the major advantage of pollen?
Water is no longer needed for fertilization
How does sperm get to the ovule in seed plants?
If a pollen grain germinates, it gives rise to a pollen tube that discharges sperm into the female gametophyte within the ovule
In gymnosperms, how does the seed coat form?
The diploid integument develops into a diploid seat coat
In gymnosperms, how does the food supply form?
The megasporaniga (2n) produces a megaspore (n) that develops into a female gametophyte (n) that then turns into the food supply
Gymnosperm or Angiosperm-> Megasporangia have one integument
G
When did the ancestors of angiosperms and gymnosperms diverge?
305 MYA
When did gymnosperms dominate?
Mesozoic
(email) Name the four phyla of gymnosperms
Cycadophyta, Ginkophyta, Gnetophyta, and Coniferophyta
(email) Give some examples of the Gnetophyta phylum, and describe the general characteristics of the phylum
Gnetum
Ephedra
Welwitschia
Vary in appearance, some are tropical and some live in deserts
(email) Describe the look and location of cycads
Large cones and palm-like leaves, Tropical and subtropical
(email) Describe the ginkgo (leaves, odor, use)
Holds onto leaves for a long time in the fall, Female seeds are smelly, Ornamental tree
What is special about the bristlecone pine?
the oldest living trees, nicknamed “methuselah”, over 1000 YA, slow growing, dry conditions, location is hidden,
What is special about the wollemi pine?
was thought to have gone extinct 2 MYA, until an Australian hiker found some, their location is hidden, but many startings are sold to try to lower the value of the old ones
(email) What is special about cycads?
Flagellated sperm
Thrived during the Mesozoic, but most are endangered now
(email) What is special about the ginkgo?
Called a living fossil, Resistant to pests and air pollution, Flagellated sperm, Two separate sexes
What are the three key features of the gymnosperm life cycle?
Miniaturization of their gametophytes
Development of seeds from fertilized ovules
The transfer of sperm to ovules by pollen
(email) What are the two key adaptations of angiosperms?
Fruit and flowers
When did did angiosperms dominate?
near the end of the Mesozoic (100 MYA) to now
Gymnosperms or Angiosperms-> Megasporangia usually have two integuments
Angiosperms
Gymnosperms or Angiosperms-> Dominate most terrestrial ecosystems
Angiosperms
(email) Describe the four types of modified leaves on a flower (and sub-types, if applicable)
Sepals (enclose the flower and are usually green, but may also look like petals)
Petals (attract pollinators with bright colors)
Stamens (produce pollen),
Made of anther and filament
Carpels (or pistils) that produce ovules
Made of stigma, style, and ovary