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
How are flowers sorted into complete or incomplete?
Flowers that have all four types of modified leaves are complete
Flowers that lack one or more are incomplete
In Angiosperms, where is the male and female gametophyte produced?
Male gametophytes are contained within pollen grains produced by the microsporangia of anthers Female gametophyte (embryo sac) develops within an ovule contained within an ovary at the base of a stigma
(email) Describe double fertilization (include #n)
Double fertilization (unique to angiosperms) is when the pollen tube discharges two sperm into the female gametophyte within an ovule One fertilizes the egg, while the other combines with two of the female gametophyte's nuclei and initiates development of the endosperm (3n), which feeds the developing embryo
In Angiosperms, what does the embryo consist of?
Within a seed, the embryo consists of a root and seed leaves called cotyledons
In Angiosperms, where does meiosis occur?
Flower
In Angiosperms, how is the egg produced?
The megasporocyte (2n) divides to form four cells, one of which survives to form the megaspore (n). The megaspore divides three times to produce one large cell with eight haploid nuclei. Membranes grow between these nuclei to form a multicellular embryo sac (the female gametophyte). The large egg cell is located at one end.
(email) In Angiosperms, how is the fruit produced? What is the purpose of fruit?
Fruits are formed when the ovary wall thickens and matures. They both protect the seed and aid in its dispersal, and can be fleshy or dry.
What is the possible closest relative to the common ancestor of all angiosperms?
Bennettitales
(email) What three groups form the basal taxa of the angiosperm phylogeny?
Amborella, water lilies, and star anise
What is the significance of magnoliids to the evolution of angiosperms?
Magnoliids share some traits with basal angiosperms (different arrangements of flower parts) but evolved later. They include magnolias, laurels, and black pepper plants, and are more closely related to monocots and eudicots than the basal angiosperms.
(email) Monocot or Dicot-> Netlike veins
Dicot
(email) Monocot or Dicot-> more than 2/3 of angiosperms
Dicot
(email) Monocot or Dicot-> grasses, orchids, and palms
Monocot
(email) Monocot or Dicot Matching: pollen has 1 or 3 openings
Both Monocot and Dicot
(email) Monocot or Dicot Matching: Scattered vascular tissue or rings
Both Monocot and Dicot
(email) Give some examples of the significance of seed plants
10-12 TYA we started to cultivate seeds, and were able to make permanent settlements
They are sources of food, fuel, wood products, and medicine. Six crops make up 80% of human calories.
Teosinte Video-> what were some of the things that first made people think teosinte was the ancestor of corn?
The chromosomes of teosinte and maize looked similar, and they could produce fertile offspring,
Teosinte Video-> Describe the branching in teosinte and corn
(teosinte has a lot, corn has none),
Teosinte Video-> Describe the kernels of teosinte and corn
Covered in teosinte, exposed in corn
Teosinte Video-> Describe the number of kernels in teosinte and corn
s (teosinte has one row per cob, corn has many).
Teosinte Video-> What data was gathered from the large F2 (offspring of crosses) experiment that lead the the identification of the number of gene differences?
The number of offspring from the F1 generation that would look like the original is 1/4n where n is the number of genes. About 1/500 looked like the original, so ⅘ genes were involved.
Teosinte Video-> When was the original domestication of corn? (two types of data used)
The number of mutations predicts that the original domestication was 9 TYA.
Microfossils of maize were dated with nearby fire pit charcoal to 8.7 TYA.
Teosinte Video-> Where was the domestication of corn?
Baslas Valley
Teosinte Video-> How was teosinte eaten?
Teosinte was probably eaten as popcorn.
Define micropyle
A small opening in the surface of an ovule, through which the pollen tube penetrates
The ovule is entered by a pore called the micropyle
(email) What are the characteristics of the phylum Coniferophyta?
Most are evergreens and carry out photosynthesis year round
(email) Monocot or Dicot-> 1 seed leaf
Monocot
(email) Monocot or Dicot-> Parallel veins
Monocot
(email) Monocot or Dicot-> taproot present
Dicot
(email) Monocot or Dicot-> organs in multiples of 4 or 5
Dicot
(email) Monocot or Dicot-> 2 seed leaves
Dicot
(email) Monocot or Dicot-> more than 1/4 of angiosperms
Monocot
(email) Monocot or Dicot-> fibrous roots
Monocot
(email) Monocot or Dicot-> organs in multiples of 3
Monocot
(email) What is the green revolution?
a period of time from the 1940s to the 1970s when many high yield varieties (HYV) were developed based on hybrid seeds and use of fertilizer, pesticides, etc
(email) What are GMOs? What are their advantages and disadvantages?
organisms that are genetically modified for things like additional nutrition, pest resistance, drought resistance, and herbicide tolerance. However, the resulting loss of biodiversity also produces a loss in resources.
(email) When and where did the domestication of plants occur?
twice in about 10,000 BC, with wheat in the fertile crescent and rice in east asia
(email) What is a doomsday vault?
a seed bank. The one we talked about was Svalbard, in Norway. The purpose of seed banks is to keep seeds safe from habitat destruction, climate warming, and other threats. They can be used to reintroduce extinct plant species, but unfortunately not all seeds can be stored.
(email) What are some examples of plant-based medicines?
aspirin, anti-cancer drugs from plant alkaloids, and malaria treatments
What is taxol?
used to treat breast and other cancers, comes from pacific yew
What is vincristine?
used to treat cancer, comes from rosy periwinkle
What is artemesinin?
used to treat malaria, comes from artemesia
