Ecology Review 1

Key Concetps Terminology Food Web Importance of Biodiversity Cycles of matter Human Impact humain on biodiversity Comment améliorer la durabilité 2

Ecosystem Biotic: Autotroph (producers) Heterotroph (consumers & decomposers) Abiotic: Air Water Pollution pH (acidity) Light Oxygen Nutriments Soil fertility

Levels of Organization Biosphere = all living things on the planet Biome = a collection of ecosystems that are similar or related to one another (same vegetation) Ecosystem. Ecotone = where two ecosystems overlap Community = a collection of different species living in the same ecosystem Population = a collection the same species living in the same ecosystem Organism = a living thing made of one or more cells

vegetation aphid  ladybug spider Energy Analyse the following food chain: vegetation aphid  ladybug spider producer: heterotroph: Second trophic level: Secondary Consumers: The largest biomass: carnivore: The amount of energy at the last trophic level? 5

vegetation aphid  ladybug spider Energy Analyse the following food chain: vegetation aphid  ladybug spider producer: vegetation heterotroph: aphid, ladybug, spider Second trophic level: aphid Secondary Consumers: ladybug The largest biomass: vegetation carnivore: ladybug or the spider The amount of energy at the last trophic level? 1% 6

Pesticides What risks are associated with the use of pesticides? Alternative solutions? 7

Carbone Cycle Who produces CO2 in the atmosphere? Write the processes & the implicated chemical reactions? How do humans interrupt the carbon cycle? Discuss the consequences? 8

Extracting Energy from Plants

Leaf Cross Section

Why is photosynthesis important? Produces glucose = energy supply for living organisms. Adds O2 to the atmosphere for us to breath. Removes CO2 from the atmosphere. Facts: Tropical Forests cover 5% of Earth’s surface, yet they are contribute 30% of Earth’s Photosynthesis! World’s oceans are responsible for another 30%.

Carbone Cycle Who produces CO2 in the atmosphere? All living organisms perform cellular respiration. Decompostion (bacteria – landfill) Fossil fuels Write the processes & the implicated chemical reactions? Cellular respiration: C6H12O6 + 6O26CO2 + 6H2O Photosynthesis: 6CO2 + 6H2O + E. Solaire  C6H12O6 + 6O2 How do humans interrupt the carbon cycle? Excess amount of CO2 in the atmosphere: Combustion of fossil fuel Deforestation Discuss the consequences? Increases the earth’s temperature “Global Warming”  floods, loss of habitat, severe storms… Gets in the water cycle  acid rain aquatic ecosystem 12

Worksheet   Photosynthesis Cellular Respiration 1. What is it? A series of chemical changes in which green plants capture and convert Sun light energy to energy-rich food like sugar. A process that releases energy from glucose in the presence of oxygen. 2. Which living things use it? Only green plants and certain single-celled organisms. All living organisms 3. How is energy changed? Light energy is changed to chemical energy. Energy is released when glucose is broken down. 4. What substances does it use? carbon dioxide and water Glucose and oxygen 5. What substances does it produce? glucose and oxygen Carbon dioxide and water 6. How can it be represented? light energy + carbon dioxide + water → glucose + oxygen glucose + oxygen → carbon dioxide + water 7. Why is it important? 1. It transforms light energy into a form that living things can use to survive. 2. It produces oxygen that most living things needs to survive. To release the energy within the glucose molecule, thus allowing the cells to accomplish their daily functions.

Nitrogen Cycle The importance of nitrogen for both plants and animals. How can you increase the amount of nitrogen in the soil? Discuss Human Activities and their impact on the ecosystems and hence biodiversity. 14

Nitrogen – N2 78% of the atmosphere (N2) Nitrogen is important for proteins and DNA synthesis for all living organisms. Plants receive their nitrogen from the sol in th eform of nitrates (NO3). Animals receive their nitrogen by consuming plants and other animals. Nitrogen returns to the soil in the forms of waste (manure) or dead matter and gets into the aquatic ecosystem.

Human Activities Agriculture: Fertilizers (Synthetic & natural ), irrigation, deforestation, tractors and pesticides.

Eutrophication p. 18

WHY DOES BIODIVERSITY MATTER? Biodiversity Matters to Humans… Provide services such as… Oxygen and other nutrients (through nutrient cycling) Food, water and shelter Fertile soil for farming Medicines Natural resources (E.g. lumber, etc.) Tourism and recreation

WHY DOES BIODIVERSITY MATTER? It Matters to Ecosystems… helps ecosystems to remain stable There are many types of relationships and interactions among organisms in a community.

WHERE IS BIODIVERSITY THE GREATEST? Biodiversity hotspot The tropics (77% only 16% of Earth’s land surface) Carolinian Canada (southern Ontario) – 1%

THREATS TO BIODIVERSITY Examples of Human Activity Hunting/Poaching Introduction of Species Logging/Clear-Cutting Urbanization Overexploitation Burning Fossil Fuels Building Dams Recreation Farming/Overharvesting Tourism Many of these activities have contributed to climate change (E.g. global warming) which also has a major impact on biodiversity and ecosystems. The consequences of human activity on ecosystems can be devastating, unpredictable and complex.

Deforestation Habitat loss, which lowers the carrying capacity of an ecosystem, which in turn causes an imbalance in the food chain. Changes the climate, less rain dryer temperatures. (plants transpires). Increases the strength of storms (hurricanes..) Increase erosion, more runoff nutrients into the lake, causes eutrophication  decreasing biodiversity.

Human Interventions can be Beneficial Examples of Conservation Efforts: Public awareness campaigns Media/Marketing Eco-friendly forms of energy use and transportation Stiffer laws and penalties Creating national parks and wildlife reserves Tree-planting

Population: all the individuals of a species that occupy a particular geographic area at a certain time. Capacité biotique: It is the maximal size of population that an ecosystem can support.

Populations List the limiting factors affecting a population growth. Biotic and Abiotic Factors. Abiotic Biotic Light Water Acidity Pollution Sunlight Oxygen Competition (inter.. & intra..) Predation Symbiosis (mutualism & parasitism) Food Diseases 26

Sketch a growth curve when: Space and resources are infinite. Resources limit the carrying capacity.

Phases of a population curve Exponential phase: Rapid increase in population growth. Natality rate exceeds mortality rate. Abundant resources available. (food, water, shelter) Diseases and predators are rare. Transitional phase: Natality rate starts to fall and/or mortality rate starts to rise. There is a decrease in the number of resources. An increase in the number of predators and diseases. Population still increasing but at a slower rate. Plateau phase: No more population growth. Natality = Mortality . The population has reached the carrying capacity.  The limited resources and the common predators and diseases keep the population numbers constant.