Ch.30 - Seed Plants Flashcards
In addition to seeds, what else is common to all seed plants?
Reduced gametophytes
Heterospory
Ovules
Pollen
A ______ is an embryo and its food supply, surrounded by a protective coating.
A seed is an embryo and its food supply, surrounded by a protective coating.
Seed plants originated ~_____ million years ago, while cultivation of seed plants for food (wheat, maize, bananas) occurred ~___ thousand years ago.
Seed plants originated ~360 million years ago, while cultivation of seed plants for food (wheat, maize, bananas) occurred ~13 thousand years ago.
A seed is a multicellular structure made of wh 3 structures?
A seed is a multicellular structure made of:
Embryo (2n; new generation)
Nutritive tissue (haploid in gymno, triploid in angio)
Seed coat (from ovule covering -> maternal tissue = 2n)
In a seed, the food supply comes fr the _______ (gametophyte/sporophyte) and is ______ (haploid/diploid)
In a seed, the food supply comes fr the gametophyte and is haploid.
Note: angiosperms have triploid (3n) food source.
T/F: most gametophytes of seed plants are microscopic
True
most gametophytes of seed plants are microscopic
Sporophyte is dominant generation
Reduced gametophytes in seed plants develop from ______ inside ______, contained in parent sporophyte.
Reduced gametophytes in seed plants develop from spores inside sporangia, contained in parent sporophyte.
Seed plant gametophytes are heterosporous. What does this indicate about where they’re found and how they look?
gametophyte of each sex look different/found in different places
megasporangia → _______ → ______ (fe/male) gametophyte
microsporangia → ______ → _______ (fe/male) gametophyte
megasporangia → megaspores → female gametophyte
microsporangia → microspores → male gametophyte
The _________ is a layer of sporophyte tissue that envelops and protects megasporangium.
The integument is a layer of sporophyte tissue that envelops and protects megasporangium.
An unfertilized gymnosperm ovule is made up of ________, _________, and _________. The female gametophyte develops from the ________ and produces egg(s).
An unfertilized gymnosperm ovule is made up of integument, megasporanium, and megaspore. The female gametophyte develops from the megaspore and produces egg(s).
Label the indicated structures in the attached figure of an unfertilized ovule.
A microspore is also called a ___________, and has a wall made out of __________, which encloses and protects the _______ (fe/male) gametophyte.
A microspore is also called a pollen grain, and has a wall made out of sporopollenin, which encloses and protects the male gametophyte.
Pollination is the transfer of ______ to the part of the seed plant that contains the ______.
Pollination is the transfer of pollen to the part of the seed plant that contains the ovule.
- Typ occurs via wind or animals.
After germination and fertilization, a gymnosperm ovule develops into a _____ which consists of the _______ (gameto/sporophyte) embryo, its food source, and a ___________.
After germination and fertilization, a gymnosperm ovule develops into a seed which consists of the sporophyte embryo, its food source, and a protective coat
Label the structures in the fertilized ovule.
Label the structures in the attached gymnosperm seed.
Compare and contrast spore vs seeds.
Spores vs. seeds
Seed coating is multicellular, provides more protection
Seeds have supply of stored food, can survive longer than spores
Gymnosperms, aka “naked seeds”, have seeds that are not enclosed in _______. Instead, their seeds are exposed on modified leaves called _______, wh typ form cones called ________.
Gymnosperms, aka “naked seeds”, have seeds that are not enclosed in ovaries. Instead, their seeds are exposed on modified leaves called sporophylls, wh typ form cones called strobili.
Pine trees are gymnosperms. The pine tree itself is _______ (sporo/gametophyte).
Pine trees are gymnosperms. The pine tree itself is sporophyte.
_________ are scale-like structures packed into cones. Ovule cones (aka _________) are large, while pollen cones (aka _________) are small.
Sporangia are scale-like structures packed into cones. Ovule cones (aka megasporangia) are large, while pollen cones (aka microsporangia) are small.
Microsporocytes divide by ______ (meiosis/mitosis) producing _______ (haploid/diploid) microspores, wh dev into ________.
Microsporocytes divide by meiosis producing haploid microspores, wh dev into pollen grains.
During gymnosperm germination, the _________ forms, growing toward the (micro/megasporangium).
The _________ (micro/megasporocyte) goes through ______ (meiosis/mitosis) producing _______ (two/four/six) haploid cells.
One cell survives, becoming the _________ (micro/megaspore), and the _______ (sporo/gametophyte) develops inside.
During gymnosperm germination, the pollen tube forms, growing toward the megasporangium.
The megasporocyte goes through meiosis producing four haploid cells.
One cell survives, becoming the megaspore, and the gametophyte develops inside.
Approx how many years ago (and in wh period) did gymnosperms first appear?
305 million years ago (Carboniferous) – First fossil gymnosperms found; gymnosperms diverged fr angiosperms.
T/F: Carboniferous was dominated by seedless plants.
True
Carboniferous was dominated by seedless plants
- Gymnosperm fossils first found during carboniferous
- Permian period that followed was drier – Thick cuticle and leaves w small surface areas evolved in response to drier air
- 251 million years ago (end of Permian period; b/w Paleozoic/Mesozoic Era): gymnosperms dominate, food source for dinosaurs
What are the four phyla of “naked seed” plants?
Gymnosperms (naked seed plants):
Phylum Cycadophyta
Phylum Ginkgophyta
Phylum Gnetophyta
Phylum Coniferophyta
Describe Phylum Cycadophyta
Cycadophyta
- 2nd largest group (after conifers)
- Large cones and “palm-like” leaves
- 130 species today, thrived during Mesozoic; most are endangered today.
- Unlike most seed plants, cycads have flagellated sperm
Describe Phylum Ginkgophyta
Ginkgophyta
One surviving species – Ginkgo biloba (maidenhair tree)
- Deciduous fanlike leaves
- Resilient to air pollution
- Seeds have a v distinctive smell
Describe Phylum Gnetophyta
Gnetophyta (gnetophytes)
- 3 genera that look v diff, but are united by molecular evidence
- Welwitschia: one species, W. mirabilis found in deserts of South Africa
- Gnetum: 35 species of tropical (Africa/Asia) trees, shrubs, vines
- Ephedra: 40 species, world-wide distribution
Describe Phylum Coniferophyta
Coniferophyta
- Latin: “conus” = cone, “ferre” = carry
- Largest group (6,000 species)
- Dominate forests of North hemi
- Short growing seasons
- Mostly evergreen -> psynth on sunny winter days
- Some deciduous species (Dawn redwood)
What characterizes angiosperms? What’s the only Phyla of anigosperms? Where does the name come from?
Angiosperms
- Greek: “Angion” means container
- Phylum Anthrophyta
- 250,000 species worldwide (90% of plants)
- Angiosperms have flowers and fruits
__________ are angiosperm structures specialized for sexual reproduction.
Flowers are angiosperm structures specialized for sexual reproduction.
T/F: all angiosperms are pollinated by insects or other animals.
False
MOST angiosperms are pollinated by insects or other animals. SOME are pollinated by wind, e.g. grasses.
From the outside/base of shoot:
- _____ – green, enclose flower before it opens
- _____ – brightly colored, attracts pollinators
- _______ – produce microspores - stalk-like filament, terminal anther
- _______ – produce megaspores
From the outside/base of shoot:
- Sepal – green, enclose flower before it opens
- Petal – brightly colored, attracts pollinators
- Stamens – produce microspores - stalk-like filament, terminal anther
- Carpels – produce megaspores
Label the structures of the attached flower, and briefly describe.
From the outside/base of shoot:
- Sepal – green, enclose flower before it opens
- Petal – brightly colored, attracts pollinators
- Stamens – produce microspores - stalk-like filament, terminal anther
- Carpels – produce megaspores
Flowers may have radial symmetry or bilateral symmetry. For wh type can any imaginary line drawn thru the central axis create two equal parts?
For flowers w radial symmetry, any imaginary line
through the central axis divides the flower into two
equal parts
In bilateral symmetry, a flower can only be divided
into two equal parts by a single imaginary line
T/F: Flowers w stamens may be on the same plant as
those w carpels, or they may occur on diff plants.
True
Flowers w stamens may be on the same plant as
those w carpels, or they may occur on diff plants.
MOST species have flowers with both functional
stamens and carpels, but in some species they occur
on separate flowers
Fruits are typ a mature ______, with a wall that
thickens after fertilization
Fruits are typ a mature ovary, with a wall that
thickens after fertilization.
- Fruits can be fleshy or dry
What are some adaptations that help fruit travel?
Wind, water, animals
A mature flower on a sporophyte plant is ______ (hap/diploid) and contains ______ (male/female/both) structures.
A mature flower on a sporophyte plant is diploid and contains BOTH male and female structures.
- Mechanisms to ensure cross-pollination
A mature flower on a sporophyte plant is diploid and contains both male and female gametophytes. Describe where ea are found/produced.
Male gametophytes: inside pollen grains
produced by microsporangia of anthers
- *Female gametophytes** (embryo sac): inside an
- *ovule** contained in ovary at base of stigma
In the anther of a stamen, ea microsporangium contains __________ that divide by _______ (meiosis/mitosis) → produce _________, wh dev into a _________.
In the anther of a stamen, ea microsporangium contains microsporocytes that divide by meiosis → produce microspores, wh dev into a pollen grain.
- Microsporocytes are diploid
- Microspores are haploid
- Pollen grain is the male gametophyte; haploid
The pollen grain is the male gametophyte. Each pollen grain contains which FOUR cells?
4 cells within each pollen grain
- 2x Prothalial cells; remnant of male gametophyte
- 1x Generative cell → produces 2 sperm cells
- 1x Tube cell → produces pollen tube
Note: pollen grain is haploid (like microspore fr wh it devs), but contains TWO haploid cells (generative and tube)
Ea ovule, wh devs in the ______, contains a female gametophyte, aka ___________, wh consists of only a few cells, incl the ____.
Ea ovule, wh devs in the ovary, contains a female gametophyte, aka embryo sac, wh consists of only a few cells, incl the egg.
In the megasporangium of ea ovule, the __________ divides by ______ → produces _____ (#) megaspores → _____ (#) survives and gives rise to female gametophyte.
In the megasporangium of ea ovule, the megasporocyte divides by meiosis → produces four megaspores → one survives and gives rise to female gametophyte.
- Megasporangium are diploid
- Surviving megaspore and egg are haploid
After its release fr the anther, pollen is carried to the sticky _____ at the tip of a ______ → germinates → _______ grows down to the ovary and enters ovule thru a pore called the _______. After pollination, eventually ____ (#) sperm are discharged in ea ovule, aka ______ fertilization.
After its release fr the anther, pollen is carried to the sticky stigma at the tip of a carpel → germinates → pollen tube grows down to the ovary and enters ovule thru a pore called the micropyle. After pollination, eventually TWO sperm are discharged in ea ovule, aka double fertilization.
What is meant by “double fertilization”?
Pollen tube discharges TWO sperm into female gametophyte w/i an ovule. One sperm fertilizes the egg (forms zygote), other sperm fertilizes TWO nuclei in central cell, forming endosperm.
- Egg and sperm are both haploid → diploid zygote/embryo
- Endosperm is triploid
What function does endosperm serve?
Endosperm is a food source → nourishes developing embryo
- Endosperm is triploid (one sperm fertilizes TWO nuclei in central cell)
After double fertilization, the ovule matures into a seed. Within a seed, the embryo consists of a root and one/two seed leaves called ________.
Within a seed, the embryo consists of a root and
one/two seed leaves called cotyledons
In an angiosperm seed, the embryo and seed coat are ______ (hap/di/triploid) and the endosperm is ______ (hap/di/triploid).
In an angiosperm seed, the embryo and seed coat are diploid and the endosperm is triploid.
The seed coat is derived from ________.
The seed coat is derived from integuments.
Summary of angiosperm cycle:
The seed consists of the ______, the ________, and a _______ derived fr integuments. An ovary devs into a _____ as its ovules become seeds. After being dispersed, a seed may germinate if environ conditions are favorable. The ______ ruptures and the embryo emerges as a seedling, using food stored in _______/_______ until it can produce own food by psynth.
Summary of angiosperm cycle:
The seed consists of the embryo, the endosperm, and a seed coat derived fr integuments. An ovary devs into a fruit as its ovules become seeds. After being dispersed, a seed may germinate if environ conditions are favorable. The coat ruptures and the embryo emerges as a seedling, using food stored in endosperm/cotyledons until it can produce own food by psynth.
Angiosperms became the dominant terrestrial group approx ____ million years ago (mid-________ period)
Angiosperms became the dominant terrestrial group approx 100 million years ago (mid-Cretaceous period)
What are the two main groups of angiosperms?
Two main groups:
- Monocots one cotyledon
- Eudicots - “true” dicots, i.e. TWO cotyledon
Other groups:
- Basal angiosperms: less derived; include oldest lineages of flowering plants
- Magnoliids: more closely related to monocots and eudicots, but share some traits with basal angiosperms
Basal angiosperms have three lineages w ~100 species, incl ________
Basal angiosperms have three lineages w ~100 species, incl water lilies
Magnolids consist of ~8000 species, incl ________, and are typ woody and herbaceous
Magnolids consist of ~8000 species, incl magnolias, and are typ woody and herbaceous
Monocots comprise 25% of angiosperms, w ~70k species, incl ________
Monocots comprise 25% of angiosperms, w ~70k species, incl orchids, palm, lily, barley
Eudicots comprise 2/3 of angiosperms, w 170k species, incl ________
Eudicots comprise 2/3 of angiosperms, w 170k species, incl poppy, snow pea
A bright pink flower with deep floral tubes will most likely be pollinated by which mechanism?
- Birds w long beaks
- nocturnal animals
- Small insects
Only birds w long beaks can feed on the plant’s nectar. Meanwhile, pollen becomes attached to the top of the bird’s head, from which it is transported to other flowers as the bird continues to feed.
- Flowers pollinated by nocturnal animals (bats) are typ light-colored and highly fragrant.
- Insects such as honeybees most likely wouldn’t have access to the nectar contained in long floral tubes.
Which of the following is a trait possessed by all angiosperms?
- Free-living gametophyte
- Seeds dispersed by animals
- Seeds produced in ovulate cones
- Double fertilization.
- Pollination by animals
Double fertilization
Following pollination, the male gametophyte produces and discharges TWO sperm into female gametophyte (embryo sac).
- One sperm fertilizes the egg (forms diploid zygote).
- Other sperm fuses w TWO nuclei in central cell (produces triploid endosperm).
After double fertilization, the ovule matures into a seed. The zygote develops into a sporophyte embryo, and the triploid central cell of the female gametophyte develops into endosperm, tissue rich in starch and other food reserves that nourish the developing embryo.
In gymnosperms, the seed coat develops from the integument. In angiosperms, the seed coat develops from the __________.
- Ovary wall
- receptacle
- integuments
- endosperm
- female gametophyte
In gymnosperms, the seed coat develops from the integument. In angiosperms, the seed coat develops from the integuments.
- embryo and its food supply are enclosed by a seed coat formed fr two integuments of the ovule.
Ovary wall gives rise to the pericarp.
Receptacle is part of the flower stem.
Endosperm is a nutritive tissue for the dev embryo.
The seed coat’s most important function is to provide protection for the __________.
The seed coat’s most important function is to provide protection for the sporophyte embryo.
- A seed consists of seed coat (derived fr sporophyte tissue called the integument) surrounding the spore wall, a food supply, and the embryo.
Which of the following is not a gymnosperm?
- Ephedra
- Ginkgo
- Sequoia
- Coconut palm
- Douglas fir
Which of the following is not a gymnosperm?
- Ephedra
- Ginkgo
- Sequoia
-
Coconut palm.
- Coconut palms are angiosperms.
- Douglas fir
The diploid generation of the plant life cycle always __________.
- is called the gametophyte
- produces eggs and sperm
- is larger and more conspicuous than the haploid stage
- develops from a spore
- produces spores
The diploid generation of the plant life cycle always __________.
- is called the gametophyte
- produces eggs and sperm
- is larger and more conspicuous than the haploid stage
- develops from a spore
- produces spores
In addition to seeds, what is a trait unique to seed plants?
Pollen
A pollen grain consists of a male gametophyte enclosed within the pollen wall. The pollen wall protects the pollen grain as it is transported by wind or by hitchhiking on an animal to the female gametophyte, also miniaturized and protected within the megasporangium of the sporophyte.
