Edited Invalid date
23.5 Evolution of Seed Plants: Full Adaptation to Land
Many Native Americans use maidenhair fern to stop bleeding during childbirth, and it's the source of a cold medicine.
Take the life cycle of a fern and compare it to that of a moss.
The gymnosperm and angiosperm life cycles have key components.
During the dispersal stage of their life cycle, seed plants use seeds.
The seed coat and stored food allow an embryo to survive harsh conditions until the environment becomes favorable for growth.
The stored food is a source of nutrition for the growing seed.
The male gametophytes are called pollen grains.
sperm move toward the female gametophyte through a growing pollen tube.
Because the male gametophyte moves to the female gametophyte, there is no need for external water tofertilize.
The less water a plant needs for reproduction, the more it can take advantage of new resources and become more abundant.
Gymnosperms and angiosperms are the two groups of seed plants that are alive today.
Gymnosperms are cone-bearing seed plants and the ovules are not completely enclosed at the time of pollination.
In angiosperms, the ovules are completely enclosed within the diploid sporophyte tissue, which becomes a fruit.
The first type of seed plant that appeared was a plant called a seed fern.
The seeds of the Devonian were progymnosperms.
It's possible that these were the type of progymnosperms that gave rise to today's gymnosperms.
Gymnosperms are still woody, but many are nonwoody.
The Carboniferous swamp forests were part of the Progymnosperms.
conifers, cycads, ginkgoes, and gnetophytes are "seed" The conifers are more plentiful than the other types of gymnosperms.
pines, firs, cedars, hemlocks, redwoods, cypresses, yews, and junipers are some of the conifers.
There are a lot of areas in the north covered in evergreen forests.
The leaves of pines conserve water because they have a thick cuticle.
In the life cycle of the pine, the sporophyte is dominant, the pollen grains are wind blown, and the seed is dispersed.
Pine trees are the most common of the conifers.
Page 424 pleasant smell and their beauty make pines attractive additions to parks and gardens.
The needles and bark of pines are rich in vitamins A and C and can be used to make teas that ease symptoms of a cold or cough.
pine nuts and pine oil are used to scent a number of household and personal care products.
The cycads are native to tropical and subtropical forests.
In landscaping, cycads are used.
Their large leaves grow in clusters at the top of the stem, which makes them resemble palms or ferns.
The cycad's trunk is unbranched even if it reaches a height of 18 m.
Cycads have seed cones and pollen on their plants.
The cones, which grow at the top of the stem surrounded by leaves, can be more than a meter long with a weight of 40 kilogrammes.
The life cycle of a gymnosperm is not shown by cycads because they are pollinated by insects.
The sperm swim to reach an egg and the pollen tube burst in the vicinity of the archegonium.
Gymnosperms are cone-produced and cycads are one of them.
A ginkgo tree has leaves that are broad and seeds that are small.
This specimen has pollen in it.
cycads are in danger of extinction because they grow very slowly.
Male trees are usually preferred for planting because of the foul odor caused by the seeds.
Ginkgo trees do well in city parks and are resistant to pollution.
In Asia, ginkgo seeds are considered to be a delicacy.
Blood circulation has been improved by using extracts from ginkgo trees.
Like cycads, the pollen tube of ginkgo burst to release multiflagellated sperm that swim to the egg produced by the female gametophyte, located within an ovule.
There are three living genera and 70 species of plants that are very diverse in appearance.
All gnetophytes have the same structure, except for xylem and strobili, which have different constructions.
The reproductive structures of some gnetophyte species produce fruit and insects play a role in pollination.
The flowering plants are called "seed").
Six times the number of other plant groups combined, they are an extremely large and successful group.
From fresh water to desert and from the frigid north to the tropics, angiosperms live in all sorts of habitats.
It would be impossible to exaggerate the importance of angiosperms.
The broad evergreen trees of tropical forests are included in the angiosperms.
Most garden plants are flowering.
All fruits, vegetables, nuts, herbs, and grains are angiosperms.
We get clothing, food, medicines, and other commercially valuable products from them.
Over the past 12,000 years, humans have artificially selected plants to serve us better, resulting in the cultivation of plants as food crops and for other uses.
Gymnosperms are flowering plants that are enclosed within diploid tissues.
Unlike bones and teeth, the soft parts of plants are often eaten before they can be preserved.
There is a debate among paleobotanists on the origins of flowering plants.
Unlike the soft parts of plants, pollen can be used to date the appearance of a seed plant in an area.
The evolution of plants.
Plants have flowers from the Triassic.
Humans began moving away from a hunter-gatherer way of life around 12,000 years ago.
As early groups of humans began to spend more time in the same location, they needed larger and more readily available food sources.
Over time, these early farmers selected plants that produced more food with less investment of time and energy.
The highlands of Mexico were where maize was first cultivated 10,000 years ago.
By the time Europeans were in Central America in the 1500s, over 300 varieties were being cultivated.
All of the varieties can be traced back to a Mexican grass called teosinte.
Corn plants have ears that remain intact, a trait that is disadvantageous in nature but beneficial to humans.
Humans are able to harvest ears that are not shattering.
Hunter-gatherers return to the same locations year after year.
The natural vegetation at these sites would have been ideal for the colonization of species that were being cultivated by these groups.
The 1896 example shows how quickly artificial selection can change corn.
After 90 generations, the average oil content of the corn kernels had increased by 450%, and only the top 20% of oil producing individuals were allowed to reproduce.
Harvesting plants with specific characteristics can affect the population's genetic diversity.
This decline leads to a genetic bottleneck, in which various traits are lost while others increase in frequencies, giving rise to a change in the phenotypic frequencies within the population.
The practice of creating corn hybrid in the 1920s increased yields and genetic diversity.
Artificial selection has changed corn so much that it can no longer reproduce on its own.
The world's growing population, the loss of farmland, and erratic climate patterns are straining global food production.
The production of corn is dependent on the use of transgenes.
Information gained from genomic studies can be used to modify corn varieties that increase yields under growing environmental pressures.
The future of the humans who rely on maize has been opened up by genetic engineering.
It is possible to cultivate corn with a specific color, texture, and sugar content.
Corn ears are larger than grass teosinte.
Grains of teosinte are softer than corn fruits.
The angiosperm of today may be related to the first angiosperms.
This small shrub with small flowers is only found on the island of New Caledonia in the South Pacific.
The flowers are about 8mm wide, and the petals and sepals look the same, so they are called tepals.
Plants have a variable number of stamens or carpels.
The mass extinction that occurred at the end of the Cretaceous period resulted in the decline of the gymnosperms.
During modern times, angiosperms became the dominant plants.
The two major classes of angiosperms were formed after the evolutionary split that gave rise to dicots.
These plants are not included in the designation.
The "seed leaves" are what nourish the plant embryo.
Eudicot include cacti, strawberries, dandelions, and beans.
Most flowers have the same structures in common.
The flower is generalized.
Sepals, petals, stamens, and carpels make up a flower.
A stamen has an appendage.
A carpel has many characteristics.
The petals may be colored like the sepals.
Sepals are usually green and attached to the flower stalks.
The petals can be used to attract a pollinator.
The first part of the stamen is a slender stalk, the second part is a container called the anther.
Microspores produced within the anther produce pollen grains.
The seed is the ovule and the fruit is the ovary.
The distribution of seeds can be aided by fruit.
Not all flowers have all these parts.
The life cycle of a flowering plant is depicted in Figure 23.23.
Like the gymnosperms, flowering plants are Heterosporous.
The embryo sac is an egg-bearing female gametophyte that develops within an ovule of a carpel.
One of the seven cells in the embryo sac is an egg, and the other two are polar nuclei.
The polar nuclei came from opposite ends of the embryo sac.
The life cycle of a plant.
The carpel and stamens are part of the flower.
Significant stages of female gametophyte development, male gametophyte development, and important stages of sporophyte development have been divided.
When mature, pollen Page 429 grains are male gametophytes with sperm.
There are only three cells in the mature male gametophyte.
The stigma of a carpel is what pollen is transported from the anther to.
The tube cell produces a tube that carries sperm to an ovule.
The ovule becomes a seed that contains an embryo and food inside a seed coat.
As the seed matures, endosperm is absorbed by the cotyledons.
In some cases it is an accessory part of the flower.
Some fruits, such as apples and tomatoes, provide a moist covering for seeds, while other fruits, such as pea Pod and acorns, provide a dry covering.
Plants are involved in the production and development of plants.
The dispersal of pollen and seeds is required for successful completion of sexual reproduction.
Many different types of flowers have been created by dispersal of pollen and seeds.
Many insect and bird-pollinated flowers are colorful, whereas wind-pollinated flowers are usually not.
Night-blooming flowers are aromatic and white or cream-colored and attract mammals or insects.
Many flowers are adapted to attract specific pollinators, such as bees, wasp, flies, butterflies, and even bats, that carry pollen from one flower to another flower of the same type.
As flowers go from flower to flower, the region of the ovary that contains the glands that produce the nectar is filled.
Bee-pollinated flowers are usually blue or yellow and have ultraviolet shadings that lead the pollinator to the location of the nectar.
The bees' mouth parts are fused together into a tube, which they use to get their food.
The flowers look like a female wasp.
The males will engage in pseudocopulation with the female and end up with pollen on their head.
The male deposits pollen to the second flower in order to complete the cross pollination that the orchid intended.
The dispersal of seeds is aided by the fruits of flowers.
When seeds are moved by wind, gravity, water, and animals to another location, it's called dispersion.
Animals can eat fleshy fruits if they transport the seeds to a new location and deposit them when they defecate.
Because animals live in certain habitats and have certain migration patterns, they are able to deliver fruit-covered seeds to a suitable location for seed germination and plant development.
Life cycle changes have allowed pines to adapt better to land.
There are four types of gymnosperms.
The functions of the key structures are listed.
A diploid zygote is formed when sperm and egg are produced.
The gametophyte is larger and more productive than the sporophyte.
The reproductive strategies of flagellated sperm are demonstrated in the life cycle of mosses.
These plants have dispersal agents.
New plants can be grown from the underground rhizome.
Sexual reproduction is adapted to the environment and no longer requires external water.
In many angiosperms, pollen is transported from flower to flower by various pollinators.
Both flowers and fruits are only found in angiosperms and may account for the extensive colonization of the land by the flowering plants.
Pick the best answer for the question.
The moss life cycle consists of leafy, green shoots.
The sperm move from the antheridium to the archegonium by swimming.
A small, upright plant that resembles a tiny, upright pine tree with club shaped strobili and microphylls is a fern.
Microphylls have a single strand of tissue.
Ferns are dispersal agents.
Ferns have blood vessels.
Ferns have a dominant generation.
Gymnosperms have flowers.
The pine tree has needles on its leaves.
A Boston fern, a ginkgo tree, and a flowering Gerbera daisy are the plants you choose to buy at your local garden center.
View flashcards and assignments made for the note
Getting your flashcards
Privacy & Terms