1) http://youtu.be/l7WxpP4NndM
2) https://en.m.wikipedia.org
3) study.com
4) Class Notes and Worksheets
2) https://en.m.wikipedia.org
3) study.com
4) Class Notes and Worksheets
Block: 1-2
1) http://youtu.be/l7WxpP4NndM
2) https://en.m.wikipedia.org 3) study.com 4) Class Notes and Worksheets
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1) "Another characteristic of nonvascular plants that sets them apart from vascular plants is that they lack roots. Instead of roots, nonvascular plants have rhizoids, which are small hairs that insert into the substrate to keep the plant in place. Vascular plants have roots not only for support but also to soak up water that is farther away from the plant." ( Study.com) Rhizoids: 2) Vascular Plants benefit in three ways from having vascular tissue:
This is why vascular plants that are more dominant in their sporophyte stage are larger and located higher up, as they are giving the opportunity to outcompete its opponents on the ground for sunlight, food and water Non-Vascular vs Vascular Plants The two first plants to have moved onto land and adapted to better suit their needs, have a lot of similarities between the two and a lot of differences! For example, in both Bryophytes and Pteridophytes they both have an archegonium and antheridium, aswell as spores which are wind-borne and require the environment to be humid and windy before release. Both of these plants are seedless and use the process of mitosis and meiosis. The sperm of both these plants are flagellant meaning they can swim to the archegonium when fertilization is to occur. The sores that are released will both create a gametophyte in the early part of reproduction.
Differences between the two plant species consist of physical and physiological differences! Pteridophytes are vascular plants that contain vascular tissue and features. They contain a xylum which transport water from the roots to the shoots and phloems which transport photosynthesis products from the shoots to the roots. In contrast, Bryophytes do not contain any of those features as they are non- vascular which makes them smaller sized plants and located lower to the ground! Bryophytes rely on living in moist areas with lots of water because they are not vascular plants that can transport water throughout the whole plant unlike Pteridophytes! Within the gametophyte stage in Bryophytes the archegonium and the antheridium are located in two different locations whereas during the gametophyte stage in Pteridophytes, the archegonium and the antheridium are both located in the gametophyte, just at separate poles! As for the features of these two species of plants, the Bryophytes are dominant in the gametophyte stage whereas the Pteridophytes are dominant in the sporophyte stage. The Bryophytes contain capsules that release reproductive spores whereas the Pteridophytes have a sporangium that release the reproductive spores! Pteridophytes are your vascular, seedless plants that adapted to the land much better than the pioneer land plants, the Bryophytes! Plants like ferns, horsetail, adiantum and Pteris are all strong examples of Pteridophytes. Fern: Horsetail: Adiantum: Pteris:
After the first generation of plants came through (Bryophytes) it was time for change! A new species of plants came to rise. They were called the Pteridophytes. Pteridophytes are also known as Ferns! These type of plants are far more equipped with beneficial features to help them survive in areas where water isn't as abundant! In order for these plants to reproduce however, they had to utilize the Alternation of Generations method. Just like the Bryophytes, the cycle starts off with a capsule-like feature known as the sporangium releasing wind-borne reproductive spores out into the environment when windy and humid conditions occur. From there the spores will germinate, creating an immature gametophyte. This gametophyte will take its time growing and developing until it's big enough to form into a mature gametophyte. From there the archegonium located further south of the gametophyte will create its eggs for fertilization! Meanwhile, in the antheridium located up north of the gametophyte, will create flagellant sperm that will swim from the antheridium to the archegonium when there is enough water to fertilize the egg! From there, just like in the Bryophyte life cycle a diploid zygote will be created and will continue to live out of the archegonium until a young sporophyte is created! As time goes on a mature sporophyte will be created containing large fronds with sporangium on the under side. Within the sporangium meiosis will take place, creating reproductive spores once again! When the sporangium is ready and environmental conditions are key, it will release the spores into the air to restart the cycle once again.
The lifecycle of a Bryophyte can be very long and complicated, as it goes through two reproductive stages during its life which can also be identified as Alternation of Generations. The typical lifecycle of a moss starts when one of its spores lands in a mosit place. It germinates and grows into a mass of tangled green filaments called a protonemia. As the protonemia grows, it will form rhizoids that grow into the ground and shoots that grow into the air. The Green Moss plants you will see are a result of the shoots growth and development. This is the gametophyte stage of its life cycle. Gametes are formed as reproductive structures at the tips of the gametophytes. Sperm with flaggenlent or whiplike tails are produced in the antheridium and egg cells are produced in archegonium. Once the sperm is released and reaches the egg cells, the process of fertilization takes place! This process creates a diploid zygote which is the very start of the sporophyte stage. The zygote will grow directly out of the gametophyte and depend on it for water and nutrients as it grows bigger and bigger each day. Once the mature sporophyte has grow it will take the shape of a long stalk with a capsule located at the top. Inside the capsule are haploid spores which are produced by meosis! When the capsule ripens and the environmental conditions are right ( windy and humid) the capsule will open and wind-borne reproductive sores will scatter everywhere to start the cycle again!
Mosses, Hornworts and Liverworts are all prime examples of Bryohpytes that will go through this long process in order to reproduce themselves. Scientist all around the world believe that the evolution of plants relies heavily on the adaptations made by the Multicellular Green Algae. When scientist studied the differences between Multicellular Green Algae and land plants they ended up finding a lot more similarities than differences. For example, Multicellular Green Algae have the same size, color, and appearance of plants. They have reproductive cycles that are similar to those of plants . In addition, Green Algae have cell walls and photosynthetic pigments that are identical to those of plants. DNA sequences confirm that plants are closely related to certain groups of Green Algae. The alga Halimeda is found in Honduras in Central America. It has many features in common with plants.
Scientist believe that for more than 3 billion years, Earth's terrestrial surface was lifeless. Plant Life evolved in the seas from algae. Microbiologists have discovered 3 different types of algae (all apart of Kingdom Protista) that are credited as earths first "plants." The first is Brown Algae which is located in phylum heterokonitophyta. This type of algae is normally found in marine and temperate waters. Examples of some Brown Algae you might find are kelp, fucales, or dictyotales. The second is Red Algae which is found in phylum rhodophyta. These types of algae are most common in warmer, tropical waters and in temperate zones, found in deeper waters. Coralline Algae and Rhodophyceae are some example of Red Algae you might find. Last but not least, the Green Algae, a very diverse group located in phylum chlorophyta. The Green Algae species includes 3 forms: unicellular, colonial and multicellular. All forms are not to picky over where they live, as you can find them in all environments like fresh water, salt water or soil (land) The Unicellular Green Algae are very common in fresh water as part of Phytoplankton. An example of this species are Chlamydomonas. Colonial Green Algae live in long filaments or as colonial spheres. Examples of this species would be Spirogyra or Volvox. Multicellular Green Algae are mostly marine and are said to be ancestors of land plants. Sea Lettuce or Ulva are both examples of Green Algae.
Domains: Kingdoms: Archae Archaebacteria Bacteria Eubacteria Eukarya Protista, Fungi, Plantae, Animalia |
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