Environmental Science 20 - Terrestrial Ecosystems – Role of Plants 1

Unit 5- Role of PlantsOutcome(s): ES20-TE1 Examine the role plants play in an ecosystem, including ways in which humans use plants.___________________________________________________________________________TE1a. Indicator: Discuss the many roles of plants including their roles as providers of ecological goods and services as well as natural capital. (K)b. Examine the role of plants in First Nations and Metis cultures (medicinal, spiritual, nutritional, and shelter). (K, STSE)f. Analyze the relationship between plants and climate change, including plants’ roles in reducing greenhouse gases, as well as potential impacts of climate change on plant growth and distribution. (STSE)

Roles of PlantsPlants are an integral part of life on earth. As producers,

they convert energy from the sun into energy for themselves and energy that can be consumed by other organisms. This is done through the process of photosynthesis. Additionally, they also convert airborne CO2 into O2; aiding in minimizing the effects of climate change by reducing the abundance of carbon dioxide in the air and replacing it with oxygen. Plants also contribute to habitat creation and maintenance. Many organisms, big or small, live off of plants (squirrels/birds in trees, bacteria in root nodules, caterpillars on and underneath leaves). Additional vegetation lends itself to maintaining the soil by allowing it to better hold moisture and shelter it from erosion due to wind (and when these plants die, their nutrients

also add to the nutrients within the soil).

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Picture Sources http://upload.wikimedia.org/wikipedia/commons/2/20/John_Deere_2054_DHSP_forestry_swing_machine,_Kaibab_National_Forest_1.jpghttp://www.cbc.ca/inthekitchen/assets_c/2011/11/Salad2026-thumb-596x350-136535.jpg

Ecological Goods and Services - Natural Capital Despite all of its natural uses, plant life extends into human uses as well. Wood for buildings, medicines, cloth, even our fossil fuels are from pressurized plant life from millions of years ago. When discussing economics, plants provide a large part of the industry associated with natural capital (goods and services from natural sources), and are the backbone of human survival and well-being. Many goods you consider likely have a connection to plant-life in one way or another: the paper you are reading this on, the fuel for your vehicle, the desk you’re sitting at, or the building you’re inside all pertain to the importance of plant life when talking about money in our world. Not to mention the effects plant-life has on well-being and mental health. Many cities and industries spend hundreds of thousands of dollars to beautify their respective locations with plant-life.

Climate Change’s Impact on Plant Growth and Distribution Climate change and global warming has a great impact on plant growth and distribution. As climates continue to be altered in different regions of the world (more/less moisture, hotter/colder temperatures), not only do humans have to adjust but so does the plant life. CO2 levels as we know have increased in the last three hundred years at a significant rate, and as such this can promote plant growth (as they require CO2 for photosynthesis), but translate to an overgrowth of some plants which may outcompete other plants. As temperatures change, so do precipitation levels, some plants accustomed to more water consistently may receive it in smaller amounts, or areas that have been historically dry not have greater levels of moisture to adapt to. Beyond growth, this change in temperature can affect flowering times, which typically arise when temperatures begin to rise. If temperatures rise sooner (or later), flowering will occur at different times – many animals rely on flowering plants as a food source and this will affect migration patterns as well. Plants in First Nations and Metis or other Aboriginal Cultures

Three Sisters Planting – Spiritual and Nutritional Significance Three Sisters Planting utilizes three different crops that all benefit and nurture one another in

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their growth. Corn, squash and beans are planted to create a mutually beneficial ecosystem. Corn is planted first on a mound and after it has grown about four inches, with beans placed around this mound. Between each of these mounds squash is planted as well. The corn gives the bean vines something to grow and climb up, while getting additional support from the wind with the beans helping to anchor the

corn stalk. The beans fix nitrogen in the soil contributing to soil fertility, adding the nutrient nitrogen to the soil. The squash vines act as a shade for the ground keeping moisture in and limiting sunlight for weeds to emerge from. Nutritionally they also complement each other. “Corn is a good source of carbohydrates (energy). Beans provide essential amino acids and protein. Squash provides important vitamins, and squash seeds yield [essential] vegetable fats that the other two foods lack.” -http://www.goshencommons.org/2013/03/planting-the-three-sisters/ and http://www.reneesgarden.com/articles/3sisters.html.

The connectedness between these plants has huge implications concerning spirituality within these cultures. Observing how well these plants work together and contribute to a healthy diet lead to implications of their existence to be a gift from the creator. When observing this mutualistic relationship in nature, it is only natural to relate that connectedness to what we may share with one another or the environment.

Medicinal Plants had an impact in treating ailments of First Nations people. Many of these plants are still used today in modern medicine to treat conditions. For a list of some examples visit the website below:http://www.nativeorchid.org/dorisMedicinalPlantTraditionalUses.htm

https://www.glenbow.org/

Shelter Trees and lumber provide shelter for humanity of many backgrounds. In the creation of Tipis large pieces of wood were needed to build them. In a much more primitive sense, trees as they stand an serve as a means for shelter from severe weather conditions if there is no other location available. Vikings even built turf homes in Greenland and Newfoundland in the past with the plants acting as a good insulator for the heat inside the home.http://www.ecokids.ca/pub/eco_info/topics/first_nations_inuit/shelter.cfm

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(Bag End)

http://downloads.bbc.co.uk http://fc02.deviantart.net

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__________________________________________________________________________TE1c. Indicator: Explain how plant morphology and physiology determines the role of plants in an ecosystem (e.g., leaves and photosynthesis, stems support and conduct fluids, roots anchor, absorb and store starch).(K)d. Interpret the relationship between photosynthesis, respiration, and net primary productivity. (K)

Plant Morphology and Physiology – Leaves and Photosynthesis Plants are very complex multicellular and eukaryotic organisms. They are capable of sexual reproduction and asexual reproduction, yet are aided in this growth by animals such as birds and bees. As producers, plants convert energy from the sun typically through photosynthesis in their leaves, but there is great variation between plants in terms of their leaf structure, stem structure, nutrient transfer and root structure (both to the naked eye and microscopically). Plants have adapted a variety of means to life on land. They have a waxy coating called a cuticle which helps it keep moisture inside. They have stomata underneath leaves which open and close allowing CO2 to enter the plant for photosynthesis. When the stomata open, plants lose moisture (water vapour). Similar to how we lose moisture when we sweat or exhale. However, this loss of water through transpiration actually allows water to travel from the roots to the tips of the plant to replace what was lost (through a change in pressure aided by the adhesion and cohesion of water). It’s important to note that plants do not just use photosynthesis to create sugar for other creatures to consume, in order to transport nutrients throughout the plant they also perform cellular respiration, but not to the extent other non-producer organisms do.

Vascular vs. Nonvascular PlantsEarly plants that adapted to land were likely

much shorter and didn’t need a means to transport nutrients throughout the body. Mosses, liverworts and hornworts and belong to this group and typically grow short (< 3cm in height) and close to water bodies or areas rich in moisture (which is why they do not need a nutrient transport system). They also act as great protectors of soil erosion at the base of larger plants like trees.

Larger plants, like humans, need a means to transport nutrients and water through their bodies (like arteries and veins). Vascular plants have two conductive tissues, xylem and phloem. Xylem allows water to flow from the roots to the top of the plant (aided by the capillary action of water). Phloem is the tissue that allows nutrients to be transported to where they’re needed (help leaves grow, extend

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stem). A large portion of vascular plants bear seeds for their means of reproduction, and many times these seeds are enclosed within fruit, which serve as a food source for organisms. Interestingly, some plants use this sweet taste to transport their seeds. When an animal consumes the fruit and expels the seed in their waste, that seed now has an abundance of nutrients (like fertilizer) to grow with. These adaptations to other organisms that plants utilize lends itself to the integral role plants play in ecosystems. Different plants serve different purposes depending on the size, and the size and growth of a plant is typically dependent on their stems, leaves and roots.

Growth Growth in plants usually occurs at specific regions in the plant, since they can grow throughout their entire lives without a fixed size. These growing regions are called meristems and are found at the

tips of stems and branches, at the tips of roots (apical), and in joints where leaves attach to stems (axillary). Primary plant growth occurs as a plant elongates in some way (root gets longer, stem gets longer). Secondary plant growth occurs by making the plant thicker or wider in diameter.

StemsStems come in a variety of forms.

Woody (trees), herbaceous (flowers), vines (grapes), and shrubs (multiple, thin stems). Woody plants adapted this way to allow them to grow to larger heights (the solid wood allows the plant to endure winds and support the weight of the rest of the plant). These plants also serve as homes and shade for other organisms around it. For the plant itself however, the two main functions of the stem is to hold leaves up to the sunlight (photosynthesis occurs in the leaves), and to transport nutrients and water throughout the roots and leaves.

Roots Roots absorb water and other nutrients from the soil, store some of these absorbed nutrients, as well as provide an anchor or base for the plant to keep itself in the ground. Two types of roots exist: fibrous (grass) or taproots (carrots). Each type of root has different benefits, fibrous roots spread out and absorb more water, while taproots anchor a plant better and can reach much deeper into the ground for water (better able to access deep groundwater). As these roots absorb nutrients for the plant to use, they also may be used to store excess carbohydrates created by the leaves in photosynthesis. Carrots, turnips, and sweet potatoes are examples of plants with roots that store these carbohydrates as starch. While the leaves create carbohydrates for the plant to function, the roots are responsible for the uptake of many other important nutrients that allow photosynthesis to occur – see Table 31-3 below.

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Table 31 – 3 Essential Mineral Nutrients in PlantsMacronutrients Elements

Absorbed as Use in Plants

Nitrogen NO3-, NH4

+ Part of proteins, nucleic acids, chlorophyll ATPPhosphorus H2PO4

- Part of nucleic acids, ATP, phospholipids, coen-zymes

Potassium K+ Required for stomatal opening and closing, en-zyme factor

Calcium Ca2+ Part of cell walls and cell membranesMagnesium Mg2+ Part of chlorophyllSulphur SO4

2- Part of proteinsMicronutrients El-ement

Absorbed as Use in Plants

Iron Fe2+ Part of cytochromes in electron transportManganese Mn2+ Required by many enzymesBoron B(OH)3 Thought to be involved in carbohydrate trans-

portChlorine Cl- Required to split water in photosynthesisZinc Zn+ Essential part of many enzymesCopper Cu2+ Essential part of many enzymesMolybdenum MoO4

2- Required for nitrogen metabolism

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Sweet Potatoes - what we eat is the plan’s starch storage.http://microfarmgardens.com/storage/sweet-potatoes.jpg?__SQUARESPACE_CACHEVERSION=1403363741727

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Net Primary Productivity Plants take in energy from the sun and convert it into chemical energy through photosynthesis. Recall that through this process that only a small percentage of energy from the sun is actually utilized by the plant, and that the process of photosynthesis occurs in the plant’s leaves (to be transported elsewhere through the stem and to the roots of the plant or other parts if needed). Gross Primary Production is a term used to describe how much biomass a plant creates over time (basically how much energy is converted from the sun into some form of the plant). In its daily functions, plants undergo cellular respiration as well to maintain growth its well-being. After considering how much usable energy a plant produces, we subtract how much it uses in respiration and that gives us its net primary productivity. Different parts of the world have higher levels of net primary productivity, and this correlates to how much plants life is created in a given area that contributes to an ecosystem (another way to think of it is: net or actual amount of green material – producers – created from sunlight). Gross and net primary productivity are measured in units of mass per unit area per unit time interval. In terrestrial ecosystems, mass of carbon per unit area per year (Cg/m2/yr) is most often used as the unit of measurement (below uses kcal or the amount of usable stored chemical energy is created). This means that when looking at a specific area, over a certain amount of time, we measure how much carbon (producer’s body cells) are created. In our last unit, we mentioned that swamps and marshes have a high level of net primary productivity, and the importance of this is because they grow very dense areas of vegetation and we know that greater levels of vegetation typically have positive impacts on the environment since they contribute more consumable energy to ecosystems.

http://www.globalchange.umich.edu

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__________________________________________________________________________TE1e. Indicator: Assess factors (e.g., monocultures, climate change, pesticides, and disease) which influence plant pollination and reproduction. (K)

Plant Pollination and Reproduction Factors

Monocultures and Disease As agriculture has developed over time, the crops that grow best are typically harvested for their seeds as well to grow more crops. Unfortunately this can be problematic if you have an entire crop of a plant that are genetically identical, and are therefore equally susceptible to disease. Additionally, this has impacts on the natural spread of pollen and reproduction in those plants (ie. When they’re all the same, there is likely no significant variation in offspring if it has two identical parents – this can lead to vulnerability to disease or even a combination of recessive traits that may be detrimental to the crop’s health).

Climate Change Climate change has a pretty obvious impact on the plant’s regular pollination and reproduction cycles. Typically plants coordinate growth/reproduction times with certain temperatures/weather conditions (spring); if these temperatures come sooner (or later) as a result of climate change, this can throw regular reproduction cycles off balance. Additionally, having these plants attempt to reproduce sooner may occur before pollinators such as bees have adapted to the new climate and are not present to help facilitate the process, and pass their reproductive phase before other organisms can fully benefit from them, resulting in a potential decrease in food for pollinators.

Pesticides To keep crops alive long enough to harvest and feed humans, we spray pesticides to keep them safe from organisms that may consume the crop. However, this also impacts pollination and reproduction in plants. Plants require pollinators (bees) to help spread their genetic information to other members of their species, but pesticides kill a large portion of these pollinators. In the soil, pesticides hinder nitrogen fixation – which legumes perform with the help of bacteria to create nutrients in the soil. If this process is inhibited it can lead to less nutrient-rich soil, requiring more fertilizer to be added to compensate for this (which can contribute to runoff into aquatic systems). Specifically affecting plants, pesticides can also lead to poor root hair development which may make the plant less well-anchored in the soil and add to a decrease in nutrient uptake.