Ecology Review PDF

# Science Review: ## Definitions: * **Organism:** living thing * **Environment:** an organism's surroundings * **Population:** a group of organisms of the same species living together in the same habitat at the same time * **Habitat:** the place where an organism lives * **Community:** different p...

# Science Review: ## Definitions: * **Organism:** living thing * **Environment:** an organism's surroundings * **Population:** a group of organisms of the same species living together in the same habitat at the same time * **Habitat:** the place where an organism lives * **Community:** different populations living in the same habitat at the same time * **Sustainable:** an ecosystem that maintains a relatively constant set of characteristics over a long period of time * **Radiant Energy:** energy that travels through empty space * **Light energy:** visible forms of radiant energy * **Thermal Energy:** the form of energy transferred during heating or cooling * **Biogeochemical cycle:** the movement of matter through the biotic and abiotic environment * **Equilibrium:** the balance of living and nonliving things that keeps the ecosystem in homeostasis. * **Lithosphere:** LAND * **Hydrosphere:** WATER * **Atmosphere:** AIR * **Biosphere:** LIFE ## The Earth's Spheres: * Everything on planet Earth can be placed in one of 4 major "subsystems" which are also called "spheres". * Earth orbits our Sun (a star) at approximately 150,000,000 km. ### The Atmosphere: * Earth's mass creates a force of gravity strong enough to hold gases near its surface. * Earth's atmosphere is the continuous layer of gasses. * It is made up of about 78% nitrogen gas, and 21% oxygen gas. * The remaining <1% of the atmosphere includes argon, water vapor, carbon dioxide and other gasses. * The atmosphere is critical to life on Earth. * It acts like a blanket and moderates our surface temperatures. * Earth's atmosphere blocks some incoming solar radiation, which is linked to skin cancer. ### The Lithosphere: * The lithosphere is the rocky outer shell of Earth. * Consists of the rocks and minerals. * Ranges from about 50 to 150 km in thickness (150 km is about the distance to Oakville from London). ### The Hydrosphere: * Consists of all the water on, above, and below Earth's surface (e.g. oceans, lakes, ice, groundwater, and clouds). * 3% of the water in the hydrosphere is freshwater (non-salty). * 97% is contained in the oceans (salty). ### The Biosphere: * The biosphere is anything alive. * Delicate zone around Earth where life can exist. * Every condition of life has to be met and maintained. * Living things need water, space and nutrients to survive. ## Ecosystem: * Ecosystems are all the living organisms that share a region and interact with each other and their non-living environment. * Contains both **Biotic and Abiotic factors**. * Ecosystems can be small or large, have many populations or very few. * Any self-sustaining group of living and nonliving things interacting with each other can be considered an ecosystem. ### Abiotic Factors: * Non living things in an environment (e.g. terrain, sun, temperature, minerals, air, wind). * Important aspects for survival, but are not alive. ### Biotic Factors: * Include all organisms, their remains, their products, and their wastes. ## Sustainability: * Man-made or engineered ecosystems are unsustainable, this means they can only thrive and be productive with tremendous human efforts. ## The Sun: * Source of all energy required to keep life alive on Earth is radiant energy from the sun. * Provides UV and Light energy to Earth. * 70% of this energy is absorbed by the lithosphere & hydrosphere, & is converted to heat energy. * 30% is reflected into space. * 0.023% is absorbed by living organisms going through photosynthesis. * Thermal energy keeps the Earth warm, but does not provide energy for organisms to grow, & is not available at night. * Chemical energy is needed to store energy & is used by all organisms to function. ## Photosynthesis: * Plants convert light energy into chemical energy through Photosynthesis. * One of the most important processes on Earth. * Most life would not exist without it. * Organisms that photosynthesize are called **Producers** as they produce their own energy and energy for others (on land these are plants that use chlorophyll, in water it is from algae). * Most producers convert carbon dioxide and water into sugars and oxygen gas. ## Carbon Dioxide + Water + Light Energy = Sugar + Oxygen: * Some sugar can be stored as chemical energy in the roots, shoots, stem, leaves, and seeds of the plant as **Starch**. ## Cellular Respiration: * To make sugar available, plants will undergo **Cellular Respiration**. Energy is released from sugar using oxygen and producing water and carbon dioxide. * **Sugar + Oxygen = Water + Carbon dioxide + energy**. * No light is required for cellular respiration, this is always occurring in cells. * Non-photosynthetic organisms will gain energy by eating other living things. Called **Consumers**. * Consumer's cells also undergo cellular respiration using the sugars they have ingested from other organisms. ## Why the Difference? * Species in an ecosystem are influenced and limited by their surroundings and resources they require. * The big difference lies in the relationships between species in an ecosystem and their own needs for survival. ## Ecological Niches: * The function that a species serves in its ecosystem includes what it feeds on, what eats it, and how it behaves. * No two species will have identical niches, but they can overlap. * **E.g Black bear**: * Feed on tender plant parts (nuts and berries). * Supplement diet with insects and small animals * Hibernate during winter months. * Few predators other than human. ## Feeding Classifications: * A key feature to niches is how a species feeds. * **Producers** will create their energy from photosynthesis and sunlight. * **Consumers** will eat other organisms to gain energy. * **Herbivore:** Eats only producers. * **Carnivore:** Eats only other animals. * **Omnivore:** Eats both plants and animals. * **Scavenger:** Feeds on remains of already dead organisms. ## Food Chains: * Most common relationship between species is through feeding. * Easiest way to show connections is through a food chain. * A sequence of organisms which illustrates who eats who in an ecosystem. * Shows how energy is transferred from one organism to the next. ## Chemical Energy Flows Up a Food Chain: * **Not all energy is transferred, much is lost at each level**. * **Trophic Level** is used to describe the feeding level of an organism in a food chain. * **Producers** occupy the first trophic level. * **Primary consumers** the second. * **Secondary consumers** the third. * **Tertiary consumers** the fourth. * **Food chains do not exist in nature**. * They are part of a more complex set of relationships between species. * **Food webs** are far more accurate representations of how energy flows in an ecosystem. ### Food Webs: * Highly complex * Includes many different producers and consumers on all trophic levels. * Useful tools to figure out what may happen when a species is removed or added to an ecosystem. ## Ecological Pyramids: * Display relationships between trophic levels. * Uses energy, population numbers, and biomass. * Demonstrates the loss of energy and transfer at each trophic level. * Three kinds of pyramids: 1. **Energy** 2. **Biomass** 3. **Numbers** ### Ecological Pyramids: Energy: * Size of each layer represents energy amount. * Only about 10% of the total energy from each level is transferred to the next trophic level. * The higher up the trophic levels, the less energy is available. * The smaller the population size. ### Ecological Pyramids: Numbers: * Shows the number of individuals of all populations in each trophic level. * Does not always follow the same shape as a pyramid of energy as it follows population size. ### Ecological Pyramids: Biomass: * Total mass of organisms in each trophic level. * Doesn't always need to be upright as biomass can be larger in higher trophic levels. * Lower trophic levels have more energy and biomass available to them. * Herbivores are usually more numerous than carnivores. * Disruptions at lower trophic levels can have major impacts on ecosystems. * Omnivores, like humans, feed at all trophic levels. ## The Water Cycle: * In the water cycle, water continually moves through the spheres of the Earth through the processes of evaporation, condensation and precipitation. ## The Carbon Cycle: * Carbon moves between the abiotic and biotic parts of an ecosystem in the carbon cycle. * Most of this exchange occurs between carbon dioxide in the atmosphere, or dissolved in the water and photosynthesizing plants and microorganism. * Carbon is stored in carbon rich deposits (in the ground as fossil fuels) these locations are referred as carbon sinks. * Combustion of fossil fuels & deforestation are human activities that impact the carbon cycle. * Too much carbon dioxide can cause a greenhouse effect by trapping thermal energy in the atmosphere. ## The Nitrogen Cycle: * Nitrogen is an important component of our DNA and ultimately our cells. * The problem is that the nitrogen that exists in our atmosphere is not in a useable form. * Micro-organisms called “nitrogen-fixing” bacteria fixes nitrogen. * These organisms are found on the roots of legume plants (clover, beans, alfalfa, and peanuts). * They enter the food chain by passing from producer to consumer and on up the food chain. ## Ecological Succession: * Gradual and predictable changes in the composition of a community and abiotic factors. * Initiated by a disturbance (Geological events, fires, human activity). ## Primary Succession: * Occurs on soil to bare rock. * No life has previously existed. * E.g. Following a volcanic eruption, the new rock layer has never had life grow on it. ## Secondary Succession: * Disturbance has disrupted, but not destroyed, the community. * Some elements of life may remain. * E.g. Forest fires, pollution events, industrial activity, surface mining. ## Equilibrium and Change: * **Biomes** are extremely stable (change takes thousands of years, caused by climate change). * **Small scale ecosystems** are in a constant state of change (forest fires, disease outbreaks, volcanic eruptions). ## Gradual Changes: * Succession results in gradual changes in biotic factors. * Typical pattern is as follows. * Animals will also change, however the most visible signs of succession are plants: * **Pioneer Species:** Grasses, perennial plants and herbs * **Intermediate Species:** Shrubs, young trees, pine forests * **Climax Community:** Large shade trees, established old growth forests * Animals will also change, however the most visible signs of succession are plants. ### Benefits of Succession: * Mechanism to establish sustainability over long term change. * Recovery from natural, or main made disturbances. * Takes a long time, requires the removal of the disturbance. * Not all human made disturbances can be repaired through succession and require human action as well. ## Life on Earth: * 1.5 million species studied. * Actual number of species; 5 million to 50 million. * Most species on Earth have not been identified. * Canada is home to 200,000 species of plants, but only 71,000 have been identified. ## Biodiversity: * The variety of life in a particular ecosystem. * Measured by counting how many species exist in an ecosystem. * **Species Richness:** General rule for species richness. It increases as you move towards the equator. ## Introduction of Non-Native Species: * Massive cause of species loss in ecosystems. * Generally introducing new species fail because few species can survive in a completely new environment. * Occasionally a species can survive and become successful. * No population controls; predators and diseases. * Can out compete native species. * Becomes *invasive*. ## Invasive Species: * A non-native species whose intentional or accidental introduction negatively impacts the natural environment. * Over 3000 species in Canada. ### Invasive Species: Impact: * Cause significant damage ecologically and economically. * Estimated cost 1.4 trillion dollars globally #### Ecological: * Compete with or feed on native species. * Change ecosystem dynamics like energy flow and the nutrient cycle. #### Economic: * Damage to forest and crops cause financial losses. * Competition with crop plants decreases yields. * Diseases and pests can kill crops, livestock, or important pollinators. #### Tourism: * Species loss and reduced water quality will negatively impact wildlife viewing, fishing, and water-based recreation. * Waterways get clogged with invasive plants. Boating impossible. #### Health: * Disease causing organisms introduced; West Nile Virus. * Pesticides used to control species cause pollution and are health risks. ## Control of Invasive Species: * Prevention of accidental introduction is preferred but difficult. * Eggs, larvae, spores, seeds, can all arrive in imported foods and contains around the world. * Intentionally introduced species can be unpredictable and may not be studied enough. * **Chemical Control:** * Most widely used control is the use of pesticides. * Used mostly on forest and agricultural pests * Dramatically reduce crop damage, but has environmental risks * Could kill native species. * Pollute water, air, and soil * **Mechanical Control:** * Use of physical barriers or removal. * Invasive plants can be cut down, burned, or removed by hand. * Invasive animals can be hunted or trapped. * Barriers can be built into waterways to control fish. * **Biological Control:** * Challenging but effective method of controlling invasive species. * Intentional introduction of other organisms to control the population of an invasive species. * It rarely eradicates invasives species, but can control population. ## Habitat Loss: * Can backfire spectacularly. * Major harm of biodiversity. * Farmland, cities and towns, and highways have replaced most of southern Ontario's forest ecosystem. ## Loss and Fragmentation of Terrestrial Ecosystems: * Extreme example is the conversion of large areas of natural ecosystems into farmland and urban developments. * Most habitat loss in Ontario occurred during the nineteenth and early twentieth centuries for farmland. * Most recently, natural habitat has been lost to urban sprawl and transportation. ## Fragmented Ecosystem: * Loss of ecosystems results in fragmentation. * Dividing up a region into smaller parcels or fragments. * A larger area of the habitat is exposed to damaging outside influences. ## Fragmentation and Habitat Loss: * Second to climate change as the most serious threat to sustainability of ecosystems. * Expanding human populations are placing pressure on the land base to supply more food and raw materials. ## Heavy Metals: * One of the major sources of heavy metals entering ecosystems is through industrial smoke stacks. * Although smoke stacks release chemicals into the atmosphere, eventually they settle in water. ## Mercury: * Once heavy metals have entered an aquatic ecosystem, they are absorbed in small amounts by aquatic plants and algae. * Mercury (Hg) is one of the most common heavy metals in aquatic ecosystems. * It is released by coal-fired power plants because Hg is naturally found in coal in small amounts. ## Bioaccumulation: * When Hg settles in an aquatic ecosystem it is absorbed by algae...over time the amount of Hg in algae builds up - it accumulates. * The build up of a heavy metal (like Mercury) in the first organism in a food chain (like algae) over time, is called **BIOACCUMULATION**. * Since algae is the basis of many aquatic food chains, many other organisms eat it as their primary food source (small fish, shrimp, zooplankton...) * Each of these small organisms will consume quite a bit of algae in their lifetime. * Every time they feed on algae, more and more Mercury enters their body. * These small aquatic organisms are the food source of many larger aquatic animals: * salmon, trout and tuna. * Each time one of these larger fish feeds, Hg enters their body as well. * **Biomagnification**. This means that with every step in a food chain, the amount of Mercury that is consumed by the organism increases. * a process called **BIOMAGNIFICATION**. ## Forestry Practices: * **Clear cutting:** The removal of all or most trees in a given area. The most common method, and mimics a forest fire. It is economical and efficient, but has the greatest ecological impact. * **Shelterwood Cutting:** Mature trees are harvested in a series of 2 or more cuts. Cut in long narrow strips. This method leaves the shelter of mature trees between the cuts to support the regeneration of new trees. * **Selective Cutting:** Specific trees are taken at different times. The most costly but least ecological impact. ## Ecological Issues in Forest Management: * **Natural Forests** sustain themselves without being managed (they're sustainable). * **Clear cutting** is the most profitable and efficient method of harvesting trees, however, this removes the entire section of ecosystem and has other negative impacts on the ecosystem: * **Erosion of soil:** Nutrients from soil runoff into streams and interfere with fish spawning or create algal blooms. * **One or two species** are planted to replace the trees, decreasing biodiversity. * **Shelter wood and selective cutting** are eco-friendly but costly. Forestry companies use pesticides and fire reduction practices to prevent damage, but these practices can harm non-target species. ## Supply and demand: * Supply and demand influence the price of goods in the economy, with those who can afford the most often outbidding those who can't. This can be dangerous when applied to natural resources, as rare tropical trees become more expensive, leading to further species extinction ## Wildlife Management: * Ontario's wild animals are often hunted for food and sport. * The impact of hunting depends on a variety of ecological factors: * Is the population large and healthy? * Is the population increasing or decreasing? * Is the population being properly monitored? * Is the hunt uncontrolled? ## Managed hunts: * Managed hunts control species populations, especially those with no natural predators, like deer in southern Ontario. Overpopulation can cause competition and disease spread. * Humans manage deer populations by limiting hunting and ensuring the next generation's population can replace itself. ## Water: * Water is our most precious renewable resource. We drink water and use it to grow and cook our food. We use it to generate power and in many industrial and commercial processes. ## Engineered Ecosystems: * Most of the environments we find ourselves in on a daily basis are engineered ecosystems just like this one where the biotic and abiotic elements are carefully selected and maintained. * Humans are able to drastically alter our ecosystem because we are able to use tools and power them with concentrated energy sources like fossil fuels. * To live sustainably, we must not disrupt the abiotic and biotic conditions in our ecosystem such as nutrient cycles, biodiversity, and climate patterns. ## Modern Agriculture: * Many of the foods we eat are grown deliberately on farms and very few are hunted/ gathered from nature. This allows us to produce more food more efficiently without over harvesting foods from nature as our populations grow. * With global trade, many of the foods we consume in Canada are grown in other countries all over the world and shipped to our stores. * Many species farmed in Canada are non-native and have been selectively bred in different parts of the world to be nutritious and easy to grow in large quantities. ## Agroecosystems Differ from Natural Ecosystem: * Some ways agricultural ecosystems differ from Natural Ecosystems: * **Non-native species** * **Lower Biodiversity** (monocultures) * **Less species interactions** * **Abiotic elements** are artificially controlled rather than part of a cycle (watering, fertilizer, waste removal) ## Managing Soil Nutrients: * The most important nutrients for plants are nitrogen, potassium, and phosphorous. * These nutrients follow their own nutrient cycles in a natural environment. * On a farm where plants are constantly being grown on the same soil and the resulting plants are harvested and taken away, those nutrients don't get recycled back into the soil. Instead, farmers need to add fertilizers and irrigate with water from elsewhere to allow that soil to continuously be productive. ## Environmental Impacts of Fertilizer Applications: ## Explain how oil spills directly harm wildlife: * Because oil is toxic, it is slow to break down and difficult to clean up and many seabirds and seals are negatively impacted. * These animals may ingest the oil, causing severe damage to their internal organs. Also, the oil coats their bodies causing tremendous heat loss. ## Environmental Impacts of Fertilizer Applications: * Since the nutrients in artificial fertilizers are very concentrated, they often lead to higher levels than would naturally be found in an ecosystem or could be handled by natural cycles. * This can stress soil organisms and reduces the amount of organic matter in soil. These soils become susceptible to erosion. * Fertilizers can also leach into water systems, increasing the nutrient concentrations in water. * This water can experience algae blooms, become toxic to drink, and cause health problems in infants. ## Controlling the flow of water in soil: * Farmers control water on their land to ensure there is enough for plants to grow properly, and not too much that it drowns them. * They add water through irrigation, and remove water through drainage systems. * The water can be added from far away, or drained into far away water systems. * Although this can produce ideal and fertile crop lands, it removes important ecosystems like wetlands that many species need to live and breed. ## Alternative Farming Practices: * **No tillage farming:** Instead of ploughing leftover vegetation underground, farmers leave it on the surface. This helps retain nutrients, avoids compaction, and reduces erosion. It does require more pesticides because now weeds aren't ploughed away. * **Crop rotation:** Some crops use more of certain nutrients than others. Legumes also add nitrogen to the soil. Farmers alternate growing different crops to allow nutrient concentrations to rebuild each year instead of depleting them. * **Crop selection:** Farmers choose crops best suited for their particular environment. * **Organic Farming:** Uses no synthetic fertilisers or pesticides. Greater crop losses to pests and weeds, however they can charge more for their produce and save money on chemicals. ## Organic Farming Practices: * **Biological control:** Predatory insects, mites and disease-causing microorganisms prey on and infect prey species – E.g. Parasitic wasps and ladybird beetles(ladybug) * **Altered Timing:** Better timing of planting and harvesting can avoid peak pest populations. * **Crop rotation and mixed painting:** When farmers do not grow monocultures in the same location year after year, pest populations do not have the same opportunities to establish and prosper. * **Baiting pest:** Pheromone baits can be used to confuse some mating insects. ## List several methods that can be used to clean up an oil spill. * A. skimming/vacuumin * B. bioremediation * C. burning oil * D. dispersal agents ## The relationship between plastics and ocean pollution: * Plastics are responsible for significant damage in marine ecosystems. * Plastic will degrade into smaller and smaller pieces but never completely goes away. Many marine organisms mistake these plastic pieces for actual food! You can recycle more to help reduce or eliminate the occurrence of plastics ending up in the ocean. * You can also participate in community clean-up projects to be part of the solution rather than part of the problem! ## Questions: 1. Identify two factors that have changed the relationship between people and their environment, resulting in the production of pollution? * A. The human population size has drastically increased. * B. Many products we use are made from toxic and persistent chemicals. * **Pollution** is any harmful contaminants released into the environment. 2. List some examples of polluting materials: * Pesticides * synthetic fertilizers * automobile exhaust * product packaging (i.e. plastic, Styrofoam, Etc...) 3. What is acid precipitation? * It is precipitation that has become acidic by combining sulphur dioxides and nitrogen oxides with water vapour in the air. 4. Name two chemical pollutants that are responsible for acid precipitation on ecosystems: * A. Sulphur dioxide * B. Nitrogen oxides 5. Describe some of the negative impacts of acid precipitation on ecosystems: * Acid can damage vegetation and result in slower growth rates; in aquatic ecosystems as rivers and lakes become more acidic, species decline and may disappear; acid rain can chemically change the soil by depleting the nutrients needed by the plants.