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How Do Plants Grow - Things Plants Need To Grow

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Plants are everywhere around us, but how do plants grow and what makes plants grow? There are many things plants need to grow, and this article will explain more. Click here to get additional info.

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Differentiate between monocots and dictots.

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Differentiate between monocots and dictots.

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Analyze at the following figure and show your understanding (animation)

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Analyze at the following figure and show your understanding (animation)

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4.1.1 Describe what plants need to survive
4.1.2 Describe the evolution of plants to adapt for life on land
4.1.3 Explain the process of alternation of generations
Lab 4: Explore, through inquiry-based activity, the plant diversity Chapter 22 Lab Manual “Exploring Plant Diversity”
Investigate through an experiment how many different kinds of plants are in a small ecosystem

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Activity 2: Starting with the mature plant, number the steps in the order of a conifer's life cycle 

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Activity 2: Starting with the mature plant, number the steps in the order of a conifer's life cycle 

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a. Wind blows the pollen into the scales of the female cones.
b. When the seeds are developed, the cone opens and the wind carries the seeds away.
c. Mature conifers produce male and female cones.
d.  Male cones produce pollen.
e.  Fertilization occurs.
f.  Seeds develop inside the female cone.
g. The seedling becomes a mature plant.
h. A seed lands in soil and develops into a seedling.

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Prepare a presentation about the following objectives:

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Prepare a presentation about the following objectives:

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Group 1: Describe what plants need to survive (video)
Group 2: Describe the evolution of plants to adapt for life on land (video)
Group 3: Describe the evolution of plants to adapt for life on land (animation)
Group 4: Explain the process of alternation of generations (video)
Group 5: Explain the process of alternation of generations (animation)

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Prepare a presentation about the following objectives:

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Prepare a presentation about the following objectives:

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Group 1: Green algae
Group 2: Bryophytes
Group 3: seedless vascular plants
Group 4: Gymnosperms
Group 5: Angiosperms

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4.2.1 Identify the characteristics of green algae
4.2.2 Describe the adaptations of bryophytes [mosses]
4.2.3 Explain the importance of vascular tissue

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Identify the characteristics of green algae 

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Identify the characteristics of green algae 

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Chlorophyta are commonly known as green algae and sometimes, loosely, as seaweed. They grow primarily in freshwater and saltwater, although some are found on land. They may be unicellular (one cell), multicellular (many cells), colonial (a loose aggregation of cells), or coenocytic (one large cell). Chlorophyta convert sunlight to starch that is stored in cells as a food reserve.

Green Algae Characteristics

Green algae have dark- to light-green coloration that comes from having chlorophyll a and b, which they have in the same amounts as "higher plants"-the plants, including seed plants and ferns, that have well-developed vascular tissues that transport organic nutrients. Their color is determined by the amounts of other pigmentation, including beta-carotene (yellow) and xanthophylls (yellowish or brownish).

Like higher plants, they store their food mainly as starch, with some as fats or oils. In fact, green algae might have been the progenitors of the higher green plants, but that is the subject of debate.

Chlorophyta belong to the kingdom Plantae. Originally, Chlorophyta referred to a division within the Plantae kingdom comprising all green algae species. Later, green algae species living predominantly in seawater were classified as chlorophytes (i.e., belonging to Chlorophyta), while green algae species thriving mainly in freshwater were classified as charophytes (i.e., belonging to Charophyta).

The AlgaeBase database lists about 4,500 species of Chlorophyta,including 550 species of Trebouxiophyceae (mostly on land and in freshwater), 2,500 species of Chlorophyceae (mostly freshwater), 800 species of Bryopsidophyceae (seaweeds), 50 species of Dasycladophyceae (seaweeds), 400 species of Siphoncladophyceae (seaweeds), and 250 marine Ulvophyceae (seaweeds). Charophyta include 3,500 species allocated to five classes.

Habitat and Distribution of Green Algae

The habitat of green algae is diverse, ranging from the ocean to freshwater. Rarely, green algae can also be found on land, largely on rocks and trees, with some appearing on the surface of snow. They are common in areas where light is abundant, such as shallow water and tide pools, and less common in the ocean than brown and red algae, but they can be found in freshwater areas.

Invasive Species

Some members of Chlorophyta are invasive species. Cladophora glomerata bloomed in Lake Erie in the 1960s because of phosphate pollution. The rotting algae washed up on beaches and produced an odor so foul that it discouraged the public from enjoying the lakes. It became so offensive in sight and smell that it was confused for raw sewage.

Two other species, Codium (also known as dead man's fingers) and Caulerpa, threaten native plant life in coastal California, Australia, the Atlantic Coast, and the Mediterranean Sea. One invasive species, Caulerpa taxifolia, has been introduced into nonnative environments because of its popularity in aquariums.

Green Algae as Animal and Human Food and Medicine

Like other algae, green algae serve as an important food source for herbivorous marine life, such as fish, crustaceans, and gastropods, including sea snails. Humans use green algae as food, too. and it has long been part of the cuisine of Japan. There are more than 30 species of edible seaweed, which is naturally rich in minerals such as calcium, copper, iodine, iron, magnesium, manganese, molybdenum, phosphorous, potassium, selenium, vanadium, and zinc. Edible types of green algae include sea lettuce, sea palm, and sea grapes.

The pigment beta carotene, found in green algae, is used as a food coloring. Carotene also has been shown to be very effective in preventing some cancers, including lung cancer.

Researchers announced in January 2009 that green algae could play a role in reducing carbon dioxide from the atmosphere. As sea ice melts, iron is introduced to the ocean. This fuels the growth of algae, which can absorb carbon dioxide and trap it near the ocean floor. With more glaciers melting, this could reduce the ​effects of global warming. Other factors, however, can reduce this benefit; if the algae are eaten, the carbon can be released back into the environment.​​​​

Here are some quick facts about green algae:

Green algae are also referred to as Chlorophyta and, sometimes, seaweed.

They convert sunlight to starch that is stored as a food reserve.

Green algae's color comes from having chlorophyll.

Green algae's habitat ranges from the ocean to freshwater and sometimes to land.

They can be invasive, with some species fouling beaches.

Green algae are food for sea animals and humans.

Green algae are used in cancer treatment.

They could help reduce carbon dioxide in the atmosphere.

http://www.seaweed.ie/algae/chlorophyta.php

https://www.reference.com/science/characteristics-phylum-chlorophyta-bcd0eab7424da34

http://www.seaweed.ie/algae/chlorophyta.php

https://eatalgae.org/edible-seaweed/

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What to Know About Green Algae, or Chlorophyta

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Green algae include both marine and freshwater species and are used as food by marine creatures and humans.

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Describe the adaptations of bryophytes [mosses] 

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Describe the adaptations of bryophytes [mosses] 

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Learning Objectives

By the end of this section, you will have completed the following objectives:

Identify the main characteristics of bryophytes

Describe the distinguishing traits of liverworts, hornworts, and mosses

Chart the development of land adaptations in the bryophytes

Describe the events in the bryophyte lifecycle

Liverworts

Liverworts (Hepaticophyta) are viewed as the plants most closely related to the ancestor that moved to land. Liverworts have colonized every terrestrial habitat on Earth and diversified to more than 7000 existing species (Figure 1). Some gametophytes form lobate green structures, as seen in Figure 2. The shape is similar to the lobes of the liver, and hence provides the origin of the name given to the phylum.

Openings that allow the movement of gases may be observed in liverworts. However, these are not stomata, because they do not actively open and close. The plant takes up water over its entire surface and has no cuticle to prevent desiccation.

Figure 3 represents the lifecycle of a liverwort. The cycle starts with the release of haploid spores from the sporangium that developed on the sporophyte. Spores disseminated by wind or water germinate into flattened thalli attached to the substrate by thin, single-celled filaments. Male and female gametangia develop on separate, individual plants. Once released, male gametes swim with the aid of their flagella to the female gametangium (the archegonium), and fertilization ensues. The zygote grows into a small sporophyte still attached to the parent gametophyte. It will give rise, by meiosis, to the next generation of spores. Liverwort plants can also reproduce asexually, by the breaking of branches or the spreading of leaf fragments called gemmae. In this latter type of reproduction, the gemmae -small, intact, complete pieces of plant that are produced in a cup on the surface of the thallus (shown in Figure 3)-are splashed out of the cup by raindrops. The gemmae then land nearby and develop into gametophytes.

Hornworts

Stomata appear in the hornworts and are abundant on the sporophyte. Photosynthetic cells in the thallus contain a single chloroplast. Meristem cells at the base of the plant keep dividing and adding to its height. Many hornworts establish symbiotic relationships with cyanobacteria that fix nitrogen from the environment.

The lifecycle of hornworts (Figure 5) follows the general pattern of alternation of generations. The gametophytes grow as flat thalli on the soil with embedded gametangia. Flagellated sperm swim to the archegonia and fertilize eggs. The zygote develops into a long and slender sporophyte that eventually splits open, releasing spores. Thin cells called pseudoelaters surround the spores and help propel them further in the environment. Unlike the elaters observed in horsetails, the hornwort pseudoelaters are single-celled structures. The haploid spores germinate and give rise to the next generation of gametophyte.

Mosses

More than 10,000 species of mosses have been catalogued. Their habitats vary from the tundra, where they are the main vegetation, to the understory of tropical forests. In the tundra, the mosses' shallow rhizoids allow them to fasten to a substrate without penetrating the frozen soil. Mosses slow down erosion, store moisture and soil nutrients, and provide shelter for small animals as well as food for larger herbivores, such as the musk ox. Mosses are very sensitive to air pollution and are used to monitor air quality. They are also sensitive to copper salts, so these salts are a common ingredient of compounds marketed to eliminate mosses from lawns.

Mosses form diminutive gametophytes, which are the dominant phase of the lifecycle. Green, flat structures-resembling true leaves, but lacking vascular tissue-are attached in a spiral to a central stalk. The plants absorb water and nutrients directly through these leaf-like structures. Some mosses have small branches. Some primitive traits of green algae, such as flagellated sperm, are still present in mosses that are dependent on water for reproduction. Other features of mosses are clearly adaptations to dry land. For example, stomata are present on the stems of the sporophyte, and a primitive vascular system runs up the sporophyte's stalk. Additionally, mosses are anchored to the substrate-whether it is soil, rock, or roof tiles-by multicellular rhizoids. These structures are precursors of roots. They originate from the base of the gametophyte, but are not the major route for the absorption of water and minerals. The lack of a true root system explains why it is so easy to rip moss mats from a tree trunk. The moss lifecycle follows the pattern of alternation of generations as shown in Figure 6. The most familiar structure is the haploid gametophyte, which germinates from a haploid spore and forms first a protonema -usually, a tangle of single-celled filaments that hug the ground. Cells akin to an apical meristem actively divide and give rise to a gametophore, consisting of a photosynthetic stem and foliage-like structures. Rhizoids form at the base of the gametophore. Gametangia of both sexes develop on separate gametophores. The male organ (the antheridium) produces many sperm, whereas the archegonium (the female organ) forms a single egg. At fertilization, the sperm swims down the neck to the venter and unites with the egg inside the archegonium. The zygote, protected by the archegonium, divides and grows into a sporophyte, still attached by its foot to the gametophyte.

Art Connection

Which of the following statements about the moss life cycle is false?

1. The mature gametophyte is haploid.

2. The sporophyte produces haploid spores.

3. The calyptra buds to form a mature gametophyte.

4. The zygote is housed in the venter.

Statement 3 is false.

The slender seta (plural, setae), as seen in Figure 7, contains tubular cells that transfer nutrients from the base of the sporophyte (the foot) to the sporangium or capsule.

A structure called a peristome increases the spread of spores after the tip of the capsule falls off at dispersal. The concentric tissue around the mouth of the capsule is made of triangular, close-fitting units, a little like "teeth"; these open and close depending on moisture levels, and periodically release spores.

Section Summary

Seedless nonvascular plants are small, having the gametophyte as the dominant stage of the lifecycle. Without a vascular system and roots, they absorb water and nutrients on all their exposed surfaces. Collectively known as bryophytes, the three main groups include the liverworts, the hornworts, and the mosses. Liverworts are the most primitive plants and are closely related to the first land plants. Hornworts developed stomata and possess a single chloroplast per cell. Mosses have simple conductive cells and are attached to the substrate by rhizoids. They colonize harsh habitats and can regain moisture after drying out. The moss sporangium is a complex structure that allows release of spores away from the parent plant.

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By the end of this section, you will have completed the following objectives: Identify the main characteristics of bryophytes Describe the distinguishing traits of liverworts, hornworts, and mosses Chart the development of land adaptations in the bryophytes Describe the events in the bryophyte lifecycle Liverworts (Hepaticophyta) are viewed as the plants most closely related to the ancestor that moved to land.

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Explain the importance of vascular tissue

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Explain the importance of vascular tissue

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The vascular tissue in the root is arranged in the inner portion of the root, which is called the vascular cylinder. A layer of cells, known as the endodermis, separates the vascular tissue from the ground tissue in the outer portion of the root. The endodermis is exclusive to roots, serving as a checkpoint for materials entering the root's vascular system. A waxy substance called suberin is present on the walls of the endodermal cells. This waxy region, known as the Casparian strip, forces water and solutes to cross the plasma membranes of endodermal cells instead of slipping between the cells. This ensures that only materials required by the root pass through the endodermis, while toxic substances and pathogens are generally excluded. The outermost cell layer of the root's vascular tissue is the pericycle, an area that can give rise to lateral roots. In dicot roots, the xylem and phloem of the stele are arranged alternately in an X shape, whereas in monocot roots, the vascular tissue is arranged in a ring around the pith.

Root Modifications

Root structures may be modified for specific purposes. For example, some roots are bulbous and store starch. Aerial roots and prop roots are two forms of aboveground roots that provide additional support to anchor the plant. Tap roots, such as carrots, turnips, and beets, are examples of roots that are modified for food storage.

Ferns and Other Seedless Vascular Plants

Ferns, club mosses, horsetails, and whisk ferns are seedless vascular plants that reproduce with spores and are found in moist environments.

Learning Objectives

Identify types of seedless vascular plants

Key Takeaways

Key Points

Club mosses, which are the earliest form of seedless vascular plants, are lycophytes that contain a stem and microphylls.

Horsetails are often found in marshes and are characterized by jointed hollow stems with whorled leaves.

Photosynthesis occurs in the stems of whisk ferns, which lack roots and leaves.

Most ferns have branching roots and form large compound leaves, or fronds, that perform photosynthesis and carry the reproductive organs of the plant.

Key Terms

Ferns and Other Seedless Vascular Plants

Water is required for fertilization of seedless vascular plants; most favor a moist environment. Modern-day seedless tracheophytes include lycophytes and monilophytes.

Phylum Lycopodiophyta: Club Mosses

The club mosses, or phylum Lycopodiophyta, are the earliest group of seedless vascular plants. They dominated the landscape of the Carboniferous, growing into tall trees and forming large swamp forests. Today's club mosses are diminutive, evergreen plants consisting of a stem (which may be branched) and microphylls (leaves with a single unbranched vein). The phylum Lycopodiophyta consists of close to 1,200 species, including the quillworts (Isoetales), the club mosses (Lycopodiales), and spike mosses (Selaginellales), none of which are true mosses or bryophytes.

Lycophytes follow the pattern of alternation of generations seen in the bryophytes, except that the sporophyte is the major stage of the life cycle. The gametophytes do not depend on the sporophyte for nutrients. Some gametophytes develop underground and form mycorrhizal associations with fungi. In club mosses, the sporophyte gives rise to sporophylls arranged in strobili, cone-like structures that give the class its name. Lycophytes can be homosporous or heterosporous.

Phylum Monilophyta: Class Equisetopsida (Horsetails)

Horsetails, whisk ferns, and ferns belong to the phylum Monilophyta, with horsetails placed in the Class Equisetopsida. The single extant genus Equisetum is the survivor of a large group of plants, which produced large trees, shrubs, and vines in the swamp forests in the Carboniferous. The plants are usually found in damp environments and marshes.

The stem of a horsetail is characterized by the presence of joints or nodes, hence the old name Arthrophyta (arthro- = "joint"; -phyta = "plant"). Leaves and branches come out as whorls from the evenly-spaced joints. The needle-shaped leaves do not contribute greatly to photosynthesis, the majority of which takes place in the green stem.

Silica collects in the epidermal cells, contributing to the stiffness of horsetail plants. Underground stems known as rhizomes anchor the plants to the ground. Modern-day horsetails are homosporous and produce bisexual gametophytes.

Phylum Monilophyta: Class Psilotopsida (Whisk Ferns)

While most ferns form large leaves and branching roots, the whisk ferns, Class Psilotopsida, lack both roots and leaves, which were probably lost by reduction. Photosynthesis takes place in their green stems; small yellow knobs form at the tip of the branch stem and contain the sporangia. Whisk ferns were considered an early pterophytes. However, recent comparative DNA analysis suggests that this group may have lost both leaves and roots through evolution and is more closely related to ferns.

Phylum Monilophyta: Class Polypodiopsida (Ferns)

With their large fronds, ferns are the most-readily recognizable seedless vascular plants. More than 20,000 species of ferns live in environments ranging from tropics to temperate forests. Although some species survive in dry environments, most ferns are restricted to moist, shaded places. Ferns made their appearance in the fossil record during the Devonian period and expanded during the Carboniferous.

The dominant stage of the life cycle of a fern is the sporophyte, which typically consists of large compound leaves called fronds. Fronds fulfill a double role; they are photosynthetic organs that also carry reproductive structure. The stem may be buried underground as a rhizome from which adventitious roots grow to absorb water and nutrients from the soil, or they may grow above ground as a trunk in tree ferns. Adventitious organs are those that grow in unusual places, such as roots growing from the side of a stem. Most ferns produce the same type of spores and are, therefore, homosporous. The diploid sporophyte is the most conspicuous stage of the life cycle. On the underside of its mature fronds, sori (singular, sorus) form as small clusters where sporangia develop. Sporangia in a sorus produce spores by meiosis and release them into the air. Those that land on a suitable substrate germinate and form a heart-shaped gametophyte, which is attached to the ground by thin filamentous rhizoids. The inconspicuous gametophyte harbors both sex gametangia. Flagellated sperm are released and swim on a wet surface to where the egg is fertilized. The newly-formed zygote grows into a sporophyte that emerges from the gametophyte, growing by mitosis into the next generation sporophyte.

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Share and explore free nursing-specific lecture notes, documents, course summaries, and more at NursingHero.com

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Identify the reproductive structures of angiosperms

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Life Cycle of a Plant and Alteration of Generations: Examples and Videos

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When you see a parent plant and its baby plant, do you think both resemble each other? Yes, of course! Did you know the reason? The reason lies in the fact that plants also pass on genetic information to their plant offspring. Let us understand the life cycle of a plant and what alternation of generations means.

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Describe the reproductive adaptations of seed plants 

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Describe the reproductive adaptations of seed plants 

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Gymnosperms are flowerless plants that produce cones and seeds. The term gymnosperm literally means "naked seed," as gymnosperm seeds are not encased within an ovary. Rather, they sit exposed on the surface of leaf-like structures called bracts. Gymnosperms are vascular plants of the subkingdom Embyophyta and include conifers, cycads, ginkgoes, and gnetophytes. Some of the most recognizable examples of these woody shrubs and trees include pines, spruces, firs, and ginkgoes. Gymnosperms are abundant in temperate forest and boreal forest biomes with species that can tolerate moist or dry conditions.

Unlike angiosperms, gymnosperms do not produce flowers or fruit. They are believed to be the first vascular plants to inhabit land appearing in the Triassic Period around 245-208 million years ago. The development of a vascular system capable of transporting water throughout the plant enabled gymnosperm land colonization. Today, there over one thousand species of gymnosperms belonging to four main divisions: Coniferophyta, Cycadophyta, Ginkgophyta, and Gnetophyta.

Coniferophyta

The Coniferophyta division contains conifers, which have the greatest variety of species among gymnosperms. Most conifers are evergreen (retain their leaves throughout the year) and include some of the largest, tallest and oldest trees on the planet. Examples of conifers include pines, sequoias, firs, hemlock, and spruces. Conifers are an important economic source of lumber and products, such as paper, that are developed from wood. Gymnosperm wood is considered softwood, unlike the hardwood of some angiosperms.

The word conifer means "cone-bearer," a distinct characteristic common to conifers. Cones house the male and female reproductive structures of conifers. Most conifers are monoecious, meaning that both male and female cones can be found on the same tree.

Another readily identifiable trait of conifers is their needle-like leaves. Different conifer families, such as Pinaceae (pines) and Cupressaceae (cypresses), are distinguished by the type of leaves present. Pines have single needle-like leaves or needle-leaf clutters along the stem. Cypresses have flat, scale-like leaves along the stems. Other conifers of the genus Agathis have thick, elliptical leaves, and conifers of the genus Nageia have broad, flat leaves.

Conifers are conspicuous members of the taiga forest biome and have adaptations for life in the cold environment of boreal forests. The tall, triangular shape of the trees allows snow to fall from the branches more readily and prevents them from breaking under the weight of the ice. The needle-leaf conifers also have a waxy coat on the leaf surface to help prevent water loss in the dry climate.

Cycadophyta

The Cycadophyta division of gymnosperms include cycads. Cycads are found in tropical forests and subtropical regions. These evergreen plants have a feather-like leaf structure and long stems that spread the large leaves out over the thick, woody trunk. At first glance, cycads may resemble palm trees, but they are not related. These plants can live for many years and have a slow growth process. The King Sago palm, for example, may take up to 50 years to reach 10 feet.

Unlike many conifers, cycad trees either produce only male cones (produce pollen) or female cones (produce ovules). Female cone-producing cycads will only produce seeds if a male is within the vicinity. Cycads rely mainly on insects for pollination, and animals aid in dispersal of their large, colorful seeds.

The roots of cycads are colonized by the photosynthetic bacteria cyanobacteria. These microbes produce certain poisons and neurotoxins that accumulate in the plant seeds. The toxins are thought to provide protection against bacteria and fungal parasites. Cycad seeds can be dangerous to pets and humans if ingested.

Ginkgophyta

Ginkgo biloba are the only surviving plants of the Ginkgophyta division of gymnosperms. Today, naturally-growing ginkgo plants are exclusive to China. Ginkgoes can live for thousands of years and are characterized by fan-shaped, deciduous leaves that turn yellow in autumn. Ginkgo biloba are quite large, with the tallest trees reaching 160 feet. Older trees have thick trunks and deep roots.

Ginkgoes thrive in well sunlit areas that receive lots of water and have plenty of soil drainage. Like cycads, ginkgo plants produce either male or female cones and have sperm cells that use flagella to swim toward the egg in the female ovule. These durable trees are fire-resistant, pest-resistant, and disease-resistant, and they produce chemicals thought to have medicinal value, including several flavinoids and terpenes with antioxidant, anti-inflammatory, and antimicrobial properties.

Gnetophyta

The gymnosperm division Gnetophyta has a small number of species (65) found within three genera: Ephedra, , and Welwitschia. Many of the species from the genus Ephedra are shrubs that can be found in desert regions of the Americas or in the high, cool regions of the Himalayan mountains in India. Certain Ephedra species have medicinal properties and are the source of the decongestant drug ephedrine. Ephedra species have slender stems and scale-like leaves.

Gnetum species contain some shrubs and trees, but most are woody vines that climb around other plants. They inhabit tropical rain forests and have broad, flat leaves that resemble the leaves of flowering plants. The male and female reproductive cones are contained on separate trees and often resemble flowers, though they are not. The vascular tissue structure of these plants is also similar to that of flowering plants.

Welwitschia has a single species, W. mirabilis. These plants live only in the African desert of Namibia. They are very unusual in that they have a large stem that remains close to the ground, two large arching leaves that split into other leaves as they grow, and a large, deep taproot. This plant can withstand the extreme heat of the desert with highs of 50°C (122°F), as well as the lack of water (1-10 cm yearly). Male W. mirabilis cones are brightly colored, and both male and female cones contain nectar to attract insects.

Gymnosperm Life Cycle

In the gymnosperm life cycle, plants alternate between a sexual phase and an asexual phase. This type of life cycle is known as alternation of generations. Gamete production occurs in the sexual phase or gametophyte generation of the cycle. Spores are produced in the asexual phase or sporophyte generation. Unlike in non-vascular plants, the dominant phase of the plant life cycle for vascular plants is the sporophtye generation.

In gymnosperms, the plant sporophyte is recognized as the bulk of the plant itself, including roots, leaves, stems, and cones. The cells of the plant sporophyte are diploid and contain two complete sets of chromosomes. The sporophyte is responsible for the production of haploid spores through the process of meiosis. Containing one complete set of chromosomes, spores develop into haploid gametophytes. The plant gametophytes produce male and female gametes which unite at pollination to form a new diploid zygote. The zygote matures into a new diploid sporophyte, thus completing the cycle. Gymnosperms spend most of their life cycle in the sporophyte phase, and the gametophyte generation is totally dependent upon the sporophyte generation for survival.

Gymnosperm Reproduction

Female gametes (megaspores) are produced in gametophyte structures called archegonia located in ovulate cones. Male gametes (microspores) are produced in pollen cones and develop into pollen grains. Some gymnosperm species have male and female cones on the same tree, while others have separate male or female cone producing trees. In order for pollination to take place, gametes must come into contact with one another. This typically occurs via wind, animal, or insect transfer.

Fertilization in gymnosperms occurs when pollen grains contact the female ovule and germinate. Sperm cells make their way to the egg inside the ovule and fertilize the egg. In conifer and gnetophytes, sperm cells have no flagella and must reach the egg via the formation of a pollen tube. In cycads and ginkgoes, the flagellated sperm swim toward the egg for fertilization. Upon fertilization, the resulting zygote develops within the gymnosperm seed and forms a new sporophyte.

Gymnosperms are flowerless, seed-producing plants. They belong to the subkingdom Embophyta.

The term "gymnosperm" literally means "naked seed." This is because the seeds produced by gymnosperms are not encased in an ovary. Instead, gymnosperm seeds sit exposed on the surface of leaf-like structures called bracts.

The four main divisions of gymnosperms are Coniferophyta, Cycadophyta, Ginkgophyta, and Gnetophyta.

Gymnosperms are often found in temperate forest and boreal forest biomes. Common types of gymnosperms are conifers, cycads, ginkgoes, and gnetophytes.

Asaravala, Manish, et al. "Triassic Period: Tectonics and Paleoclimate." Tectonics of the Triassic Period, University of Califonia Museum of Paleontology, www.ucmp.berkeley.edu/mesozoic/triassic/triassictect.html.

Frazer, Jennifer. "Are Cycads Social Plants?" Scientific American Blog Network, 16 Oct. 2013, blogs.scientificamerican.com/artful-amoeba/are-cycads-social-plants/.

Pallardy, Stephen G. "The Woody Plant Body." Physiology of Woody Plants, 20 May 2008, pp. 9-38., doi:10.1016/b978-012088765-1.50003-8.

Wagner, Armin, et al. "Lignification and Lignin Manipulations in Conifers." Advances in Botanical Research, vol. 61, 8 June 2012, pp. 37-76., doi:10.1016/b978-0-12-416023-1.00002-1.​

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Gymnosperms are seed-bearing plants known for their "naked seeds": seeds not encased within an ovary. Examples include pines, sequoias, and ginkgoes.

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Fatma Ibrahim, Mariam Omran, Hanin, Rouda Yousef

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Maitha Aljunaibi
Mariam Al Menhali
Mahra Al Bedwawi
Fatmah Jasem
Rowda Khamis

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Mariam K, Shamma M, Alyazia S, Ayesha M, Noora A

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Mariam K, Shamma M, Alyazia S, Ayesha M, Noora A

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Group 1 : Meera Saleh, Fatima Mohammed, Shatha Waleed, Mariam Ali 

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Group 1 : Meera Saleh, Fatima Mohammed, Shatha Waleed, Mariam Ali 

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Group 1 : Meera Saleh, Fatima Mohammed, Shatha Waleed, Mariam Ali

# data[].attributes.subject
Group 1 : Meera Saleh, Fatima Mohammed, Shatha Waleed, Mariam Ali

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Mariam ahmed, fatmah jasem, maitha khaled, mahra, rowda khamis

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Rouda Yousef, Fatma Ibrahim, Mariam Omran, Hanin Khamis

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Rouda Yousef, Fatma Ibrahim, Mariam Omran, Hanin Khamis

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Noora S., Fatmah J., Meera S., Shatha W.

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Noora S., Fatmah J., Meera S., Shatha W.

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Noora Aiman, Mariam Omran, maitha khaled, rowdah yousef/khamis, mahra abdulrahman

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Noora Aiman, Mariam Omran, maitha khaled, rowdah yousef/khamis, mahra abdulrahman