Asexual reproduction
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Plants have many things that allow them to go through asexual reproduction, such as modified stems, leaves or roots. It is possible for plants to fragment their roots and for new plants to grow out of those roots. Asexual reproduction occurs through mitosis and produces genetically identical offsprings, so the plants don't have much biodiversity. If something attacked this plant (disease or predator) the offspring will most likely be targeted too, on the other side, if the plant had a successive lifestyle and its traits allowed it to easily survive in its environment then the offspring will most likely also survive due to the presence of those traits. The plant is also not required to produce reproductive organs and reproduction takes less time/energy, also the plant does not require a mate. Also the offsprings of plants that sexually reproduce have a higher chance of survival than offsprings produced sexually.
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Asexual reproduction
Plants have many things that allow them to go through asexual reproduction, such as modified stems, leaves or roots. It is possible for plants to fragment their roots and for new plants to grow out of those roots. Asexual reproduction occurs through mitosis and produces genetically identical offsprings, so the plants don't have much biodiversity. If something attacked this plant (disease or predator) the offspring will most likely be targeted too, on the other side, if the plant had a successive lifestyle and its traits allowed it to easily survive in its environment then the offspring will most likely also survive due to the presence of those traits. The plant is also not required to produce reproductive organs and reproduction takes less time/energy, also the plant does not require a mate. Also the offsprings of plants that sexually reproduce have a higher chance of survival than offsprings produced sexually.
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Sexual reproduction
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Seeds in vascular seed plants are the most important part in sexual reproduction for plants, the seed protects/carries/nourishes the embryo that will later on be planted somewhere and it will hopefully grow. Plants have developed many different ways that help the dispersal of their seeds, from allowing them to be carried by the winds, to making them attractive to predators so that when they eat the seeds they transport it with them and then eventually poop it out somewhere. This is necessary for plants to establish biodiversity in different regions and sometimes be introduced to new ecological environments. Monocots and eudicots(b) have seeds that are full of nutrients, those nutrients surround the embryo. In angiosperms this layer can be called an endosperm (a) , and it is technically contained in fruits, while gymnosperms lack this tissue.
Unlike asexual reproduction, sexual reproduction offers a more biodiverse offspring since sexual reproduction requires the union of two haploid cells. Unfortunately sexual reproduction takes up alot of time, energy and the plants are required to have a mate. Fortunately sexual reproduction offers more benefits than asexual reproduction, the offspring are more biodiverse, and if some sort of change occurs and it's parents die off it has a greater chance of surviving since it is not identical to them. Sexual reproduction allows the plant to cover more ground while reproducing (seed dispersal), and seeds can wait until the conditions are favorable for them to grow, increasing their chance of survival. There are certain plants that are capable of reproducing both sexually and asexually depending on what they think will benefit them the most. Sexual reproduction typically involves the help of other species, such as birds and insects to pollinate/fertilize the different plants, many produce substances that attract these species to insure that the plant gets a chance to reproduce. |
Succession
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Succession is the gradual cane of species in a community. The changes affect the population/existence of some species.
Primary succession happens in an environment with no life, at first it is inhabited by pioneer species (first species to colonize the territory) As time continues more and more species continue to colonize the community and slowly change the ecosystem. Eventually changes stop occurring. 1. Pioneer organism colonizes (Typically lichen, they do not require soil) 2. Mosses arrive 3. Insects follow mosses and birds follow insects 4. Small herbaceous plants grow (lichens vanish) 5. Small animals appear (mosses vanish) 6. Small mammals appear 7. Large plants appear 8. Trees begin to grow and more organisms arrive (large animals, carnivores) 9. Environment stabilizes Secondary succession occurs when humans or ecological factors disturb an area typically after the disturbance they're aren't any plants, but there is soil allowing secondary succession to occur faster than primary. |
Plant growth
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In order to properly and successfully grow, plants require certain conditions, sometimes in order to receive all the required elements the plants develop special traits through differentiation and growth. Plants continue to crow until they die, actively dividing cells (apical meristem) are responsible for primary growth which increases the height of the plant,other actively dividing cells (lateral meristem) are responsible for the plants secondary growth which increases the plant's width. Some plants undergo only primary growth due to their lack of lateral meristems.
Primary growth increases the length of the plant apical meristems divide using mitosis, once the cells multiply and become elongated they gain special tasks, and become responsible for different things. The cells functions are determined by the location of the cells in the plants. The apical meristem in the shoots provides cells for stems, leaves and sexual organs. The apical meristem in the root produces all the root cells, here they play a larger role, the root cap protects the meristem as it grows, roots can grow several centimeters throughout the day. The tissue produced by apical meristems is called primary tissue to help differentiate it from the tissue produced during secondary growth. Secondary growth occurs only in woody species, increasing the diameter or the plants each year. Examples of lateral meristems would be a vascular cambium or a cork cambium. A result of secondary growth, are the rings that are visible if a tree is cut open, the size of the rings depends on the amount of nutrients received by the plant that year |
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There are many factors that affect a plants growth, like the amount/type of light/nutrients the plant receives. Plants contain photoreceptors (molecules that detect light) that help them regulate what kind of light they absorb the way they respond to the light they absorb is called photoperiodism, throughout the day light wavelengths change and photoperiodism helps plants establish how they are going to act on that specific day or in that moment. Plants also require nutrients for survival, there are two types of nutrients: macronutrients (plant nutrients needed in bulk) and micronutrients (small quantities of nutrients). If a plant has nutrients deficiency the plants growth can suffer, for example if a plant does not have a specific amount of nitrogen the plant's growth would be stunted and the plant may have chlorosis. Therefore it is very important that plants receive their needed amounts of nutrients and sunlight in a day.
Temperature also plays a big role in plant development, plants don't have eyes or brains, they use temperature to determine the seasons and when they should start growing and developing. If the temperature starts to get wacky and jumps around from hot to cold, the plant would have a hard time deciding whether it should develop or not. This could be a problem especially if farmers have planted large quantities of seeds expecting that they be ready for harvest in October, if the temperature does not match the temperature those seeds are waiting for they will not grow and the farmer would not have his crop by October. |
Controlling plant growth
Plants have the ability to control how, when and in which direction they grow. Well the direction they grow is obvious, plants grow towards the sun, they wish to receive as much sunlight as possible in order to maximize their chances of survival, and to further advance their growth known as a chemical called the plant growth regulator. This was proven in an experiment carried out by Darwin, which involved a monocot grass species. The first experiment involved a healthy undamaged plant, and a plant with it's tip cut off, the healthy undamaged plant leaned towards the sun gathering sunlight, while the damaged plant grew straight. This demonstrated tropism, it showed that the plant's growth was affected by outside factors such as cutting off the tip. The second experiment involved a plant whose tim was covered in a translucent cap, and a plant whose tip was covered by a cap that blocked sunlight. The plant with the translucent bent towards the sun as it received it's energy, the plant with the cap that blocked sunlight grew upright and straight. This experiment demonstrated phototropism, it showed that the plants behavior was related to the way it received light. There are two more factors that affect the behavior/growth pattern of a plant, there is gravitropism, which involves a plant rearranging itself to suit it's location in response to gravity (like growing upside down or sideways). There is also thigmotropism where plants rearrange themselves depending on their surroundings (in response to touch).
The type of chemical that regulates plant growth depends on the cell types of the plant. There are five chemicals: auxins which promote cell elongation and maximize the amount of light received, gibberllins promote cell division and elongation they determine the size of the plant, cytokinins which also promote cell division and stimulate cell division in lateral buds, ethylene which is a gas which induces changes and protects the plant from environmental stress it plays a major role in fruit growing, and abscisic acid(ABA) whose primary role is to inhibit growth ABA is triggered by changes in temperature and light.
The type of chemical that regulates plant growth depends on the cell types of the plant. There are five chemicals: auxins which promote cell elongation and maximize the amount of light received, gibberllins promote cell division and elongation they determine the size of the plant, cytokinins which also promote cell division and stimulate cell division in lateral buds, ethylene which is a gas which induces changes and protects the plant from environmental stress it plays a major role in fruit growing, and abscisic acid(ABA) whose primary role is to inhibit growth ABA is triggered by changes in temperature and light.