Unit 15 Ecology Student Notes 2023 PDF

Biology Unit 15: Ecology Name: In this unit, students build on their previous knowledge of reproduction to develop their knowledge of Species, ecosystems and niches. Energy flow. Food chains. Symbiosis. Carbon Cycle....

Biology Unit 15: Ecology Name: In this unit, students build on their previous knowledge of reproduction to develop their knowledge of Species, ecosystems and niches. Energy flow. Food chains. Symbiosis. Carbon Cycle. Habitat destruction including the effect of pollution. Conservation. This unit should take approximately three weeks to complete Objective: Define species, ecosystems and niches. Revise abiotic and biotic factors of an environment. Define species, population, habitat, community, niche and ecosystem Objective: Describe energy flow in ecosystems Revise photosynthesis from Form 3 Identify that energy comes from the Sun Objective: Describe food chains Describe how energy is transferred from one individual to another Define producer, autotroph, consumer, herbivore, and carnivore Identify that multiple food chains occur in a community Objective: Describe the relationships between living things Define, and give examples of, symbiosis, commensalism, mutualism, and parasitism Discuss how the human food supply chain has changed traditional farming methods and the impact that will have on ecosystems Objective: Describe the carbon cycle and its importance to living things Describe the carbon cycle, limited to photosynthesis, respiration, feeding, decomposition, fossilisation and combustion Objective: Describe the main causes of habitat destruction Describe the impact human activities have on habitats Describe the main types of pollutants and their causes Define eutrophication and describe its causes in NZ Objective: Describe the role of conservation in preserving ecosystems Define a sustainable resource as one which is produced as rapidly as it is removed from the environment so that it does not run out Define biodiversity as the number of different species within a given area. Define conversation as the maintaining of biodiversity Discuss the role of zoos, national parks and reserves in: – reducing extinction – protecting vulnerable environments – maintaining ecosystem functions, limited to nutrient cycling and resource provision, e.g. food, drugs, fuel and genes Form 4 Unit 15 Ecology 2023 Page 1 Definitions (Whakamāramatanga) Abiotic Factors (ahuropi-kore): Non-living factors of the environment that will limit a population size Autotroph: Self-feeding producer, organism that can photosynthesise – Photoautotroph Biotic Factors (ahuropi): Living factors in the environment that will limit a population size Carnivore (kaikiko): An animal that consumes other consumers Combustion (tauhohe ngingiha): Reaction between oxygen and other substances Commensalism (noho taupuhipuhi): A relationship between two species where one benefits and the other is unaffected Community (hapori): All the organisms in an ecosystem Conservation (Papa Atawhai): Maintaining the biodiversity of an area Consumer (kaikame): An organism that gets its energy from feeding on other organisms Decomposition (whakapopo): The process where organic material is broken down into nutrients so that material can cycle back into the ecosystem Decomposer (whakapirau): An organism that gets its energy from dead or waste organic material Ecosystem (pūnaha rauropi): A defined area in which organisms interact with each other and their environment Eutrophication (whakamatūkainga inati): An excessive richness of nutrients in bodies of water, frequently due to run off of nutrients from the land that causes a dense growth of plant life Food Chain (tāhuahua): Shows the transfer of energy from one organism to the next, beginning with a producer Food Web (huirapa kai): Is a network of interconnected food chains Fossilisation: The process by which fossils (parawaeare) are formed Habitat (nōhanga): The place within an ecosystem where an organism lives Herbivore (kaiota): An organism that consumes producers Mutualism (whanaungatanga taupuhipuhi): A relationship between two species where both benefit Niche (tūranga hauropi): An organism's role in an ecosystem Parasitism (parasiti): A relationship between two species where one benefits and the other is harmed. Photosynthesis (ahotakakame): The process where plants use light energy to convert carbon dioxide and water to glucose and oxygen Population (taupori): The total number of individuals of one species in an ecosystem Producer (pūkame): An organism that that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis Respiration (tukupūngao ā-pūtau): The process where cells use oxygen to break down organic molecules, usually glucose, to release energy Species (momo): Organisms that can breed and produce fertile offspring Sustainable Resource (rawa toitū): A resource as one which is produced rapidly as it is removed from the environment so that it does not run out Symbiosis (taupuhipuhi): The relationship between species that can be beneficial or harmful to individuals Trophic level(taumata arataukai): The feeding level an organism occupies in an ecosystem Maori translations from https://paekupu.co.nz/ - Ministry of Education, NZQA Sci & Tech Terms & https://maoridictionary.co.nz Form 4 Unit 15 Ecology 2023 Page 2 Objective: Define species, ecosystems and niches. Ecology is the study of how living things interact with each other and the physical world around them. A living thing is able to carry out all of the characteristics of MRS GREN (Movement, Reproduction, Sensitivity, Growth, Respiration, Excretion, and Nutrition). A species is a group of organisms that can reproduce to produce fertile offspring. Members of a species often have similar structural and behavioural features. For example, all Pukeko have a similar body shape and arrangement of feather colour. A population is made up of members of the same species that are living and interacting in a defined area at the same time. For example, the Pukeko that live on Raoul Island. The size of a population in an ecosystem is determined by Biotic (living) and Abiotic (non-living) factors that exist in the ecosystem. Abiotic factors are the non-living factors in an ecosystem that; determine what type of ecosystem occurs, which organisms will exist there and the size of the populations of these organisms e.g. the number of kauri trees is determined by the soil type and climate. Biotic factors are the interactions between communities in the forest. The habitat of an organism is the place where it is found. It is comprised of the abiotic factors. Pukeko tend to found near vegetated swamps, streams or lagoons that are near open grassy areas and pastures. The niche of an organism is the role that it carries out in its environment. For example, the Pukeko eats stems, shoots, leaves and seeds of grasses and rushes. They can also eat insects, spiders and earthworms. They are cooperative breeders that are territorial. They have been known to attack other birds, cats and stoats to protect their nest. No two species can occupy the same niche. A community is the interactions between all of the populations that are found in a habitat. For example, the Pukeko eat rushes and compete with Weka for nesting spaces. The ecosystem is the interaction between the abiotic and biotic factors of a given area. Form 4 Unit 15 Ecology 2023 Page 3 Objective: Describe energy flow in ecosystems All energy in an ecosystem comes from the Sun. Plants capture light energy and use the process of photosynthesis to transform it into a form that can be transferred from one species to another. Photosynthesis: Sunlight Carbon Dioxide + Water Glucose + Oxygen Chlorophyll Animals are able to get energy by eating other organisms and consuming glucose. When the glucose is broken down by the cells it releases energy to be used by the animal in other processes. Organisms that carry out photosynthesis are referred to as producers. They are also called autotrophs because they are a self-feeding producer. This is because they use the products of photosynthesis in other processes such as respiration. Organisms that get their energy by feeding on other organisms are called consumers. Consumers can eat both plants and animals. An animal that consumes plants to get energy is called an herbivore. A carnivore is an animal that gets its energy by eating other animals. Omnivores are animals that eat both plants and animals. Decomposers break down dead or waste material and have an important role in making nutrients available to other organisms. Objective: Describe food chains A food chain shows how energy is transferred from one organism to another. It starts with the producer. It is used to represent the flow of energy through an ecosystem. The arrows show the direction of the flow of energy. Plants are the producers in a food web and animals can be described as a primary, secondary or tertiary consumer. A primary consumer is an animal that eats plants. A secondary consumer is an animal that eats herbivores and a tertiary consumer is an animal that eats secondary consumers. The position of an organism in a food chain is referred to as its trophic (feeding) level. At each level, there is only a small amount of energy available to be passed onto the next level. This is because organisms use energy to carry out their life processes. Because only 10% of energy is available to be passed to the next level it is rare to see food chains have more than five trophic levels. An example of a New Zealand food chain Tawa Kereru Stoat Producer Primary Consumer Secondary Consumer Autotroph Heterotroph Heterotroph Herbivore Carnivore 1st Tropic level 2nd Tropic Level 3rd Tropic level Form 4 Unit 15 Ecology 2023 Page 4  Food Webs Only a very few organisms consume one other organism to gain the energy they need to live. Those that do are under a high threat of going extinct. A food web is a network of all of the food chains in a community and shows how energy flows through the ecosystem. It is possible for a consumer to occupy more than one trophic level. Below is a food web for a New Zealand ecosystem. Kiwi Stoat Miro Tawa Invertebrates s Kereru Tui Kow Kowhai Rat Possum Form 4 Topic 18 Ecology 2023 Page 5 Objective: Describe the relationships between living things In every community there are different relationships between individuals. Symbiosis is the relationship between species. These relationships can be one of three types: Mutualism is a relationship where both species benefit. For example: The bright red or yellow mistletoe flowers attract birds’ like Tui. The birds feed off the nectar of the flowers and the mistletoe is pollinated. Commensalism is a relationship where one species benefits and the other is neither helped nor harmed. For example: barnacles grow on whales. The barnacles benefit because the whales provide them with a habitat. The whales are not affected by the barnacles. Parasitism is a relationship where one species benefits and the other is harmed. For example: mistletoe grows on Pohutukawa tree. The mistletoe benefits because it grows its root into the tree and takes nutrients and water. This harms the Pohutukawa tree. Humans have changed many food webs and the relationships between humans and other species. This is because there are more people that require food. Traditional farming methods involve a wide range of plants and animals. This has changed to large areas being dedicated to single crops. This change has led to an increase in the use of fertilizers, herbicides and pesticides to increase the yield of crops. Intensive farming has led to habitat destruction, pollution and a reduction in wildlife. Objective: Describe the carbon cycle and its importance to living things Carbon is found in most of the chemical compounds that make up living organisms. Plants get their carbon from the atmosphere as carbon dioxide. Animals get carbon from plants and other organisms. There is a finite amount of carbon on Earth. The carbon cycle traces the movement of carbon between the atmosphere and living things. During photosynthesis plants use light and carbon dioxide to make glucose. Some of the glucose is used to make starch, cell walls, proteins and other compounds found in plants. When animals eat plants, the plant material is digested and the carbon is absorbed and can be used to make up the compounds found in animal tissues. Form 4 Topic 18 Ecology 2023 Page 6 Fossilisation occurs when the carbon in dead organisms is trapped and compressed. The carbon may form fossil fuels such as coal, oil and natural gas. Respiration is the process where cells use oxygen to break down glucose into carbon dioxide and water. The carbon dioxide and water are excreted as waste products. The carbon dioxide returns to the atmosphere. Decomposition is the process where dead organisms and waste products are broken down and the stored carbon is released into the environment. This allows them to be used by producers in the ecosystem. When fuels like wood, coal or petrol are burned they release carbon dioxide into the atmosphere. This process is called combustion. Objective: Describe the main causes of habitat destruction When groups of Humans obtained food by gathering fruits, leaves or roots and by hunting animals they had a smaller impact on the environment. This is because they existed in smaller groups and the demands on the environment to produce were lower. The development of agriculture meant that humans were able to support larger groups as they changed the local environment to produce more food. This was done by changing the plants and animals that were present. Food supply: As groups of Humans got larger, they needed more food to feed everyone. This lead to the development of agriculture. Humans changed the environment so that it suited their needs. Large areas of forests and woodlands were cleared and replaced by farmland. This land was cleared of a complex community that was made up of trees, shrubs, wild flowers and grasses. It was then replaced by a single plant species such as rice, wheat or beans which would be harvested and replanted every year. Any organism that feed on, infects or competes with the crop plant is destroyed as part of normal farming practises. Ecosystem destruction: Ecosystem and therefore the habitats of organisms are being destroyed for the following reasons: Increased area needed for food crop growth, livestock production and housing The extraction of natural resources (over harvesting) Pollution and climate change Humans have altered food webs by changing the species present in an area. Deforestation can lead to extinction, soil erosion, flooding and carbon dioxide build up in the atmosphere. Form 4 Topic 18 Ecology 2023 Page 7 Pollution: Pollutants – things that contaminate environment such as sewage water, harmful chemicals and gases Eutrophication These plants die and are broken down by oxygen consuming decomposing bacteria The drop in oxygen in the water source causes all living organisms to die The main causes of eutrophication in New Zealand are the agriculture, meat and dairy processing industries. Form 4 Topic 18 Ecology 2023 Page 8 Objective: Describe the role of conservation in preserving ecosystems A sustainable resource is one that can be produced as rapidly as it is removed from the environment so that it does not run out. In traditional approaches to food collection, restrictions were placed on the collection of food like Kina to ensure that there would be enough for future years. Raw materials like metal ores and fossil fuels are non-renewable and will run out one day. Alternative sources of energy need to be developed. Biodiversity is short for Biological Diversity. Biodiversity is all of the different populations present in an ecosystem. The greater the number of different populations, and therefore species, the greater the biodiversity. A field containing 100 000 identical wheat plants has a very low biodiversity. A meadow containing 500 different species of flower has a high biodiversity. A rainforest that contains millions of species has a very high biodiversity. Why maintain biodiversity? Scientists tend to put the reasons to maintain biodiversity into 3 groups. 1. Biodiversity required for human use. - Medicinal reasons: All of the medicines used by doctors to treat disease comes from chemicals in plants and animals. Loss of organisms through extinction will mean that the unique chemicals that those organisms have will be lost forever. - Food reasons: 95% of the food eaten by humans is provided by 35 organisms. A changing climate may mean that humans may have to find other organisms to use to provide sources of food. - Genetic reasons: Organisms also provide a source of genes for breeding or genetic engineering. If one of the major food crops is effected by a disease closely related organisms in the wild may have to be used to provide a gene that provides immunity to that disease. 2. Biodiversity to maintain nature. - Keystone species: Certain species are called keystone species. Without them the whole ecosystem will change. The change is often irreversible. There are many examples of keystone species being removed from an ecosystem and the ecosystem collapsing. Wolves, wooley mammoth and sea otters are all examples of keystone species. - In New Zealand, Snapper are an example of a keystone species. Snapper eat kina, and when too many Snapper are caught in an area the kina population increases rapidly. Kina eat algae from the rocks and, in doing so, remove the kelp. Without Kelp all of the other organisms move away or die. These regions without kelp are called the kina barrens. 3. Biodiversity for future of the earth. - Aesthetics and guardianship: Humans are on Earth for a short period of time. There is a responsibility to ensure that ecosystems are looked after so that the long term survivability of species can be ensured. Form 4 Topic 18 Ecology 2023 Page 9 Conservation Conservation is the maintaining of biodiversity. The biodiversity of an area can be affected by: Habitat destruction Introduction of Alien Species Over harvesting plants and animals International Trade in plants and animals Pollution Climate Change These can reduce the population of a species and can make it harder for them to survive. A species is endangered when there is a large reduction in the size of the population. Conservation efforts include monitoring and protecting species and their habitats. The goal of conservation is to reduce the number of species becoming extinct, protecting vulnerable environments and helping to ensure things like nutrient cycles and resources continue. Zoos, National Parks and Marine Reserves have an important role in conservation. Zoos play a role in conservation through offering captive breeding programmes and education on the importance of maintain habitats and biodiversity. Not everyone agrees that Zoos help conservation efforts. Why? National Parks are areas of preserved habitat. These are areas that have native plants and wildlife. They protect these areas from development and allow people to visit and see these plants and animals as well as learn about them. Marine Reserves protect areas from activity like fishing. The Cape Rodney- Okakari Point Marine (Goat Island) Reserve has played an important role in replenishing the populations of fish found around the Reserve. Form 4 Topic 18 Ecology 2023 Page 10