1. Alteration of generation life cycle in plants
As shown in the picture above, most of (or all of) the plants continue their lives in an infinite cycle like this. There is neither a starting point nor an ending point in this cycle. So I would just randomly pick a point to start with, which is Sporophyte!
Sporophyte, which produces individually reproductive spores, is the diploid phase of the plants in the life cycle. The process to produce spores is Meiosis. When these spores become mature, both male and female gametophyte are formed. Gametophyte, was given the name because it produces gametes, is the haploid phase of the plants. Then the sperms and the eggs that produced by male and female gametophytes fuse to form a zygote, a process known as Fertilization. Undergoing mitosis, the zygote will grow up and become a mature Sporophyte, which is diploid because of the combination of two haploids (sperm and egg).
The life forms of plants constantly change between Sporophyte and gametophyte. Therefore, all plants on earth can immortally exist as the life cycle of plants continues forever.
Sporophyte, which produces individually reproductive spores, is the diploid phase of the plants in the life cycle. The process to produce spores is Meiosis. When these spores become mature, both male and female gametophyte are formed. Gametophyte, was given the name because it produces gametes, is the haploid phase of the plants. Then the sperms and the eggs that produced by male and female gametophytes fuse to form a zygote, a process known as Fertilization. Undergoing mitosis, the zygote will grow up and become a mature Sporophyte, which is diploid because of the combination of two haploids (sperm and egg).
The life forms of plants constantly change between Sporophyte and gametophyte. Therefore, all plants on earth can immortally exist as the life cycle of plants continues forever.
2. Describe the characteristics and life cycles of the following classifications of plants
a. Bryophyte
Characteristics: Bryophyte is considered as the first plant on the land, hence, it is not fully evolved. It does not have vascular tissues and its dominant stage is Gameotophyte. Also, its gametophyte requires wet environment to reproduce because its sperms are flagellated. Its sporophyte reproduces through spores.
Characteristics: Bryophyte is considered as the first plant on the land, hence, it is not fully evolved. It does not have vascular tissues and its dominant stage is Gameotophyte. Also, its gametophyte requires wet environment to reproduce because its sperms are flagellated. Its sporophyte reproduces through spores.
Life Cycle: Bryophyte is still a comparatively primitive plants in the Plantae Kingdom, because it still has a dominant stage of gametophyte. The male and female gametophyte produce sperms and eggs through mitosis with their sexual organs (archegonium for female and antheridium for male). The sperms swim to the archegonium and form zygotes with the eggs, a process called fertilization. Each of the zygotes will then grow into a mature sporophyte, which produces spores (a reproductive structure) through meiosis. The spores grow up to be mature male or female gametophytes, completing the Bryophyte's life cycle.
b. Pteridophyta
Characteristics: Having moved from sea to earth, the early plants on land needed to overcome the desiccation. Therefore, those plants who cannot successfully evolve in favour of dryer environment died. Pteridophyte, yet was not fully evolved, got huge advantages to survive because they had a dominant sporophyte which gave them a vascular tissues to transport water and nutrients. With this system, Pteridophyte can grow bigger and have a structural support. Like Bryophyte, the Pteridophyte has flagellated sperms and uses spores for reproduction.
Characteristics: Having moved from sea to earth, the early plants on land needed to overcome the desiccation. Therefore, those plants who cannot successfully evolve in favour of dryer environment died. Pteridophyte, yet was not fully evolved, got huge advantages to survive because they had a dominant sporophyte which gave them a vascular tissues to transport water and nutrients. With this system, Pteridophyte can grow bigger and have a structural support. Like Bryophyte, the Pteridophyte has flagellated sperms and uses spores for reproduction.
Life Cycle: As the plants developed, the complexity of sporophyte let it become dominant in plants' life cycle. Meanwhile, the mature gametophyte of Pteridophyte were developed to be a small piece. It has both archegonium and antheridium on it to produce sperms and eggs. Likewise, the sperms would swim to the archegonium and form zygotes with eggs through fertilization. The zygotes will then grow into mature sporophytes which are diploid plants in the life cycle. Beneath the fronds of Pteridophyte, sori can be found. Within a sorus, large amounts of spores (haploid) are produced inside each sporangium. These spores will then be released and each of them can grow to be a independent gametophyte (either female or male).
c. Gymnosperm
Characteristics: As the geographic and climatic change occurred on the Earth, the plants needed to evolve and adapt to the environment. Therefore, in Gymnosperm, gametophyte is no longer the dominant stage. Also, Gymnosperm developed deep roots that allow it to live in drier conditions. Most significantly, seeds are found in Gymnosperm and are used to protect embryos and distribute their species. Because of this, Gymnosperm do not need water for reproduction. To stand the harsh temperature in the north, Gymnosperm has a natural antifreeze inside their needle leaves. Besides, Gymnosperm maintains many characteristics from Pteridophyte such as heterospory, vascular tissues, and pollen.
Characteristics: As the geographic and climatic change occurred on the Earth, the plants needed to evolve and adapt to the environment. Therefore, in Gymnosperm, gametophyte is no longer the dominant stage. Also, Gymnosperm developed deep roots that allow it to live in drier conditions. Most significantly, seeds are found in Gymnosperm and are used to protect embryos and distribute their species. Because of this, Gymnosperm do not need water for reproduction. To stand the harsh temperature in the north, Gymnosperm has a natural antifreeze inside their needle leaves. Besides, Gymnosperm maintains many characteristics from Pteridophyte such as heterospory, vascular tissues, and pollen.
Life cycle: Gymnosperm has a dominant sporophyte which has both male and female cones grow on it. The male cone has many spore sacs within it, containing haploid spores (produced through meiosis) which produce male gametophytes (pollen grains) through mitosis. On the other hand, the female cone contains ovules, which also produces spores through Meiosis. With the help of wind, the male gametophyte may be blown into the female cones and grow through mitosis to reach the eggs produced by the female spores. After the fertilization is done, a diploid zygote is formed and will then grow to be a mature sporophyte.
d. Angiosperm
Characteristics: Angiosperm is the last major advance in plant evolution. Although the presence of the flowers seems to be the biggest change occurs on the Angiosperm, their actual advance is the evolution of specialized reproductive structure. Therefore, Angiosperm maintains lots of similar features that are not related to reproduction. From this point on, most angiosperm plants started to develop vector pollinated methods to spread their gametes with the help of animals (mostly insects). Because of this, a parallel evolution happened between angiosperms and animals.
Characteristics: Angiosperm is the last major advance in plant evolution. Although the presence of the flowers seems to be the biggest change occurs on the Angiosperm, their actual advance is the evolution of specialized reproductive structure. Therefore, Angiosperm maintains lots of similar features that are not related to reproduction. From this point on, most angiosperm plants started to develop vector pollinated methods to spread their gametes with the help of animals (mostly insects). Because of this, a parallel evolution happened between angiosperms and animals.
Life cycle: As with the Gymnosperm, the Angiosperm (meaning "seed container" in Greek) has a dominant stage of sporophyte. Similarly, an Angiosperm also possesses both male and female reproductive organs -- which are stamen and carpel. On the stamen, there is a microsporangium which produces haploid pollen grains (containing sperms). On the other hand, the ovule, sheltered within the ovary of the carpel, contains megasporangium which produces haploid megaspores. Only one of four megaspores eventually survives and become an egg (1n) after another three division. When both anther and stigma mature, each of the pollen grains stuck on the stigma would develop a pollen tube to reach the eggs in ovules. When the sperms from pollen grains and eggs in ovules combine, zygotes (2n) are formed. (The fertilization occurs on Angiosperm is special because endosperms, which are triploid, are also formed besides zygotes, being known as double fertilization.) After these process, the zygotes will then grow mature with several protections. A seed is consisted of a tough seed coat, a endosperm served as food resource and a embryo. Usually, the ovaries surrounding the seed also grows bigger and become fruits. The embryos inside seeds will later become mature sporophytes. Eaten by animals, they are carried and therefore widely spread on the earth.
3. describe the organization of an angiosperm including the functions of each part you describe
The Angiosperms have four main organ system:
-Leaves: gas exchange is the main function of the leaves. Having many stomata, the leaves are able to allow gas exchange when water is plentifully absorbed and prevent it when water is lacked. This function enables the angiosperms' cellular processes, such as photosynthesis.
-Stems: it works as the structural support for the whole plant. Besides, the vascular tissues inside it allows the transportation of materials on both direction (up and down). When mitosis occurs, more cells are formed on the stems and this results in the growth of plants.
-Roots: Generally, there are three types of roots: tap root, fibrous root, and adventitious root. Although the shape of roots are different, they have the similar function to absorb water and minerals from the soil. Also, it also works as anchor to stabilize the plants.
-Flowers: having modified leaves (sepals, petals, stamens and carpels), it plays a role as the attraction of pollinators and a vector-pollinated reproductive system.
-Leaves: gas exchange is the main function of the leaves. Having many stomata, the leaves are able to allow gas exchange when water is plentifully absorbed and prevent it when water is lacked. This function enables the angiosperms' cellular processes, such as photosynthesis.
-Stems: it works as the structural support for the whole plant. Besides, the vascular tissues inside it allows the transportation of materials on both direction (up and down). When mitosis occurs, more cells are formed on the stems and this results in the growth of plants.
-Roots: Generally, there are three types of roots: tap root, fibrous root, and adventitious root. Although the shape of roots are different, they have the similar function to absorb water and minerals from the soil. Also, it also works as anchor to stabilize the plants.
-Flowers: having modified leaves (sepals, petals, stamens and carpels), it plays a role as the attraction of pollinators and a vector-pollinated reproductive system.
Carpel: the female reproductive organ in a flower, consists of Stigma, Style and Ovary.
-Stigma: it is on the top of a carpel, functioning as the receptive tip. Stigma is the place where pollen from the anther sticks and germinates.
-Style: it is long and slender, acting as the connection of Stigma and Ovary.
-Ovary: it holds several ovules inside, which are the destination of pollen grains. Pollen grains grow through style and finally reach ovules, providing the opportunities for fertilization of sperms and eggs.
Stamen: it is the male reproductive organ of a flower which produces pollen grains.
It is composed of two parts -- Anther and Filament.
-Anther: it is the oval-shaped structure on the top of a Stamen, containing a sporangium inside it which is used to produce pollens. When certain amounts of pollen grains are accumulated, the Anther will burst to release them.
-Filament: it is a similarly tall and slender structure as Style of the Carpel. It functions to support the Anther.
Petal: It is the modified leaves which are usually bright in colors. The purpose of petal's existence is to attract specific pollinators.
Sepal: It is another kind of modified leaves of flowers which are often green. It functions as the protection for the flower during its bud stage. Also, it provides support for pedals when blooming.
-Stigma: it is on the top of a carpel, functioning as the receptive tip. Stigma is the place where pollen from the anther sticks and germinates.
-Style: it is long and slender, acting as the connection of Stigma and Ovary.
-Ovary: it holds several ovules inside, which are the destination of pollen grains. Pollen grains grow through style and finally reach ovules, providing the opportunities for fertilization of sperms and eggs.
Stamen: it is the male reproductive organ of a flower which produces pollen grains.
It is composed of two parts -- Anther and Filament.
-Anther: it is the oval-shaped structure on the top of a Stamen, containing a sporangium inside it which is used to produce pollens. When certain amounts of pollen grains are accumulated, the Anther will burst to release them.
-Filament: it is a similarly tall and slender structure as Style of the Carpel. It functions to support the Anther.
Petal: It is the modified leaves which are usually bright in colors. The purpose of petal's existence is to attract specific pollinators.
Sepal: It is another kind of modified leaves of flowers which are often green. It functions as the protection for the flower during its bud stage. Also, it provides support for pedals when blooming.
4. drawings of the slides from the algae, bryophytes and pteridophytes microscope lab.
- Chlorophyta (Green Algae)
- Bryophyta
Moss Sporangium (Capsule)
The structure that is underneath the fronds (Bryophyte's leaves), storing and releasing the spores.
The structure that is underneath the fronds (Bryophyte's leaves), storing and releasing the spores.
- Pteridophyta
Fern --> Prothallium
The gametophyte stage of a Pteridophyta plant. Having Archegonia on the upper side and Antheridia on its bottom.
The gametophyte stage of a Pteridophyta plant. Having Archegonia on the upper side and Antheridia on its bottom.
Fern Frond (Sori)
This image shows how a fern frond's side view looks like.
This image shows how a fern frond's side view looks like.
- Analysis
1. Q: What forms of Chlorophyta did you view? How did you know to which form each specimen belonged?
A: I viewed 4 forms of Chlorophyta, they are Chlamydomonas, Volvox, Spirogyra and Ulva (also known as sea lettuce). I can differentiate them because these specimens have unique shape, color and size. For example, the Chlamydomonas is a unicellular and non-colonial creature and it appears in the microscope as a lonely small circle. The Ulva, appears to be purple in color, is very different to others who have green or blue color. Also, the Chlorophyta has a very unique shape like ropes. These characteristics of different Chlorophyta allows us to separate them.
2. Q: What are the antheridium and archegonium? What is their function?
A: The Antheridium is the male structure of plants (only appears in gametophyte) which produces the flagellated sperms. Archegonium is the female structure which produce eggs. During the fertilization, the sperms from Antheridium swim to the Archegonium and fuse with the eggs to form a zygote. The zygote will grow through a process of mitosis and become a sporophyte, allowing the plants to live on and reproduce through the Alteration of Generations.
A: I viewed 4 forms of Chlorophyta, they are Chlamydomonas, Volvox, Spirogyra and Ulva (also known as sea lettuce). I can differentiate them because these specimens have unique shape, color and size. For example, the Chlamydomonas is a unicellular and non-colonial creature and it appears in the microscope as a lonely small circle. The Ulva, appears to be purple in color, is very different to others who have green or blue color. Also, the Chlorophyta has a very unique shape like ropes. These characteristics of different Chlorophyta allows us to separate them.
2. Q: What are the antheridium and archegonium? What is their function?
A: The Antheridium is the male structure of plants (only appears in gametophyte) which produces the flagellated sperms. Archegonium is the female structure which produce eggs. During the fertilization, the sperms from Antheridium swim to the Archegonium and fuse with the eggs to form a zygote. The zygote will grow through a process of mitosis and become a sporophyte, allowing the plants to live on and reproduce through the Alteration of Generations.
3. Q: How are Bryophytes and Pteridophytes similar and different?
A: Bryophytes and Pteridophytes have many similarities. They are both in the Plantae Kingdom, meaning that they are both eukaryotic, multicellular, and photoautotrophic. They both have same cell wall structure and organelles. Also, they continue their lives through the Alternation of Generations, changing between Sporophyte (diploid) and Gametophyte (diploid).
However, these two plants have significant differences. The most significant difference is that the Bryophytes are non-vascular plants, meaning they do not have xylem and phloem while Pteridophytes have them. Having the xylem and phloem, the Pteridophytes are able to transport the water and nutrient to every part of themselves, allowing them to grow bigger than Bryophytes. Also, the dominant phage (a stage in which the plants stay longer) of Pteridophytes is the Sporophtye while that of the Bryophytes is the Gametophyte. Another difference is that the Pteridophytes have a rhizome, which is more like a true root, and the Bryophytes have a rhizoid, which is not a true root.
A: Bryophytes and Pteridophytes have many similarities. They are both in the Plantae Kingdom, meaning that they are both eukaryotic, multicellular, and photoautotrophic. They both have same cell wall structure and organelles. Also, they continue their lives through the Alternation of Generations, changing between Sporophyte (diploid) and Gametophyte (diploid).
However, these two plants have significant differences. The most significant difference is that the Bryophytes are non-vascular plants, meaning they do not have xylem and phloem while Pteridophytes have them. Having the xylem and phloem, the Pteridophytes are able to transport the water and nutrient to every part of themselves, allowing them to grow bigger than Bryophytes. Also, the dominant phage (a stage in which the plants stay longer) of Pteridophytes is the Sporophtye while that of the Bryophytes is the Gametophyte. Another difference is that the Pteridophytes have a rhizome, which is more like a true root, and the Bryophytes have a rhizoid, which is not a true root.
4. Q: What is the Prothallus and what is its function?
A: Prothallus is the Gametophyte stage of the Pteridophytes. Having archegonium and antheridium, fertilization happens in this stage and zygotes are formed. The zygotes will then grow to be sporophytes.
Other characteristics:
A: Prothallus is the Gametophyte stage of the Pteridophytes. Having archegonium and antheridium, fertilization happens in this stage and zygotes are formed. The zygotes will then grow to be sporophytes.
Other characteristics:
- It has a heart shape.
- It grows independently.
- It has rhizoids.