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Science 421. Ecology The study of the interaction of living things & their environment What else does it mean these days? Ecology is. Chapter 1 - Diversity in Ecosystems. The Earth’s regions differ in their: Temperatures Light intensity Water availability Weather Species
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Science 421 Ecology The study of the interaction of living things & their environment What else does it mean these days? Ecology is...
Chapter 1 - Diversity in Ecosystems • The Earth’s regions differ in their: • Temperatures • Light intensity • Water availability • Weather • Species • Read pages 8 & 9 and complete question 1.
1.1 The Silence of the Frogs • Amphibians are found almost everywhere there is water on the planet. • Amphibians have two lives and live within two ecosystems: • 1. Eggs laid in water grow into a tadpole; • 2. Froglet (lose their tail and adapt to living on land and breathing air). • Croaking Frogs...
Over 30% of North American frogs and toads are in trouble. A change in either of their ecosystems can result in a decline in amphibian population. • Amphibians are an indicator species, meaning if they start to die off, it is a sign that the ecosystem is in trouble. • Complete questions 1 - 6 on page 13.
Factors Affecting Frog Populations • 1. Loss of Habitat – Road construction, deforestation, etc. • 2. Air and Water Quality - Frogs are able to breath through their thin skin, therefore pollutants are able to pass through their skin. • 3. Ultraviolet Radiation – Causes skin damage to amphibians. • 4. Climate Change - Global warming increases temperatures and reduces wetlands/habitats. • Planet Earth Frogs...
Use your text & define the following terms in your notes: • Ecosystem • Decomposers • Herbivores • Food Chain • Detritus • Carnivores • Producers • Omnivores • Consumers
1.2 Canada’s Endangered Species • Canada has over 250 species of plants and animals that are at risk. There is a classification system to describe the risk to each species.
Classification Description/Example • Vulnerable At risk due to declining numbers in some areas. • Example: Grey Fox – Ontario
Classification Description/Example • Threatened Likely to become endangered if factors are not reversed. Ex.- Wood Bison
Classification Description/Example • Extirpated No longer exists in specific areas, but can be found in others.(Black bear no longer on PEI since 1930.)
Classification Description/Example • Endangered Close to extinction in all parts of Canada. Ex.-Eastern Cougar
Classification Description/Example • Extinct A species that does not exist anywhere. Ex.-Passenger Pigeon • Complete questions 1, 2 and 4 on page 15.
1.3 Extinction in the Modern World Humans have influenced the process of extinction for many species over the past 50 years.
Extinction Timeline • 1600 - 1900 -An average of one species every 4 years. • 1980 –present - An average of over 10,000 per year.
Causes of Extinctions • Asteroids - Asteroids impacted with the Earth & caused a large cloud of dust blocked light from the sun, & set off many volcanoes.
Climate Change - A change in a species’ environment forces them to adapt or die.
Pressure of Competition- 2 species may compete for the same food sources and/or habitat. One wins, the other adapts or dies. • Human Factors - Logging, oil exploration, expanding cities, expansion of agriculture, introduction of new species (purple loosestrife)
Effects of Extinction • Biodiversity is the variety of life on Earth. It is the number of species in an ecosystem. The loss of one species impacts the entire food chain & ecosystem. • YouTube - Official video of the International Year of Biodiversity 2010
Restoring Balance • Due to the effects on a food chain, it is extremely difficult to restore the balance once a species has been removed • Questions 1-3 pg. 19
Pestsare organisms that cause problems for humans. • Why are pests such as mosquitoes, termites, caterpillars and weeds needed? • Mosquito larvae provide food for fish and adult mosquitoes are food for birds. • Some insect “pests” are needed by plants for pollination, while others, such as wasps, help decompose tissues of dead plants and animals. • Weeds: source of food for animals, & can help anchor the soil, preventing erosion.
Define the following Ecology Terms: • Abiotic • Biotic • Population • Community
Ecology -the study of how organisms interact with each other. • Abiotic factors- non-living things in an ecosystem. Ex:- light, soil, wind, temperature • Biotic factors -living things in an ecosystem • Population -all of the members of the same species living in an ecosystem. • Community - all of the populations of species in an ecosystem. • Do # 1-5 on pg. 23.
Example: A pond ecosystem • Consists of a habitat with populationsof aquatic plants, waterside plants, micro-organisms (in the mud at the bottom of the pond), fish and birds. The organisms together make up a community of living things.
DO NOT COPY DOWNEcologists can study: • - A population and how it interacts in the ecosystem. (Coyotes) • - A community and how all species interact (biotic factors). • - An ecosystem including all biotic factors and the physical environment, or abiotic factors.
Quiz! • Identify each of the following as either biotic or abiotic. • Identify each of the following as either a species, a population, community or ecosystem. Grass Worms Temperature Soil Marsh The Mallard ducks in a marsh All fish in the stream The white spruce trees behind the school The trees, birds, insects, mammals, plants and amphibians in the forest Brookvale Demonstration Woodlot
An ecotone is a transition area between two different ecosystems where species from each can interact. There is often greater diversity in the ecotone than in either of the two ecosystems bordering it. • An area with greater biodiversity is less fragile consumers have more food sources; don’t have to rely on only 1 source. An ecotone guards against extinction.
1.8 Comparing Ecosystems • Artificial ecosystems -human made. (Ex. farms, parks) • A natural ecosystem - made by nature. Species are able to interact with their surroundings freely. Humans will still have an impact on the ecosystem but they do not control it.
Albedo effect - % of light an object reflects. The higher the Earth’s albedo, less energy is absorbed and therefore less energy is available for maintaining the Earth’s temperature. 30% Photosynthesis: 0.023% 70%
1.11 Following Energy Movement in Ecosystems YouTube - How Ecosystems Work | Biology | Ecology • Energy is constantly moving within our ecosystems. To understand how living things gain their energy we must look at trophic levels (position in the food chain). • Most ecosystems only contain about three trophic levels consisting of: • 1. Autotrophs - make their own food - producers. • 2. Heterotrophs - can’t make their own food – consumers (can be broken down into sub-levels)
Fourth Trophic Level Tertiary Consumers • Eat secondary and primary consumers. (Heterotroph) • Bear, cougar • Third Trophic Level Secondary Consumers • Eat primary consumers and producers. (Heterotroph) • Eagles, wolves • Second Trophic Level Primary Consumers • Eat producers for food. (Heterotroph) • Deer, mice, bugs • First Trophic Level Producers • Make their own food from basic nutrients and sunlight. (Autotrophs) • Grass, berries, trees
A food web is graphical representation of the feeding relationships between organisms in an ecosystem. In reality a single organism can be a part of many food chains.
DO NOT COPY • Ecosystems with the greatest biodiversity are the most stable they have complex food webs and therefore the removal of one consumer or one producer may have only a small impact on the ecosystem and the overall web.
Sunlight • Source of all energy on earth • Less than 1% is used for photosynthesis (conversion of solar energy into chemical energy sugar molecules)
Energy Transfer • Each time energy is transferred from one organism to another, there is a change of form. (i.e. plant used most of the sun’s energy to grow only a small fraction of sun’s energy is passed onto an animal that eats the plant) • As you move through a food chain, less energy is available to each organism.
LAWS OF THERMODYNAMICS • 1st Law – Energy is not created nor destroyed, only changed from 1 form to another • 2nd Law – During an energy transfer, some of the energy is converted into thermal energy or heat which is released to the environment
Energy use by organisms: • - Growth, repair and survival • - Given off as heat and used in respiration. • - Excretion (although decomposers actually use this energy in a different food chain). • - Transport of materials in the body, and for movement. • All the energy used in these ways returns to the environment, and is not available to the next trophic level.
Human Use of the Energy in Ecosystems • Two main revolutions have increased our energy demands on ecosystems and have reduced the amount of energy available to other organisms. • 1. Agricultural Revolution • 2. Industrial Revolution
Section 2.1 Cycling of Matter in Ecosystems • Please answer the following questions in your notebooks. Please use your textbook and provide complete answers. Define matter. • What is an organic compound? • What is an inorganic compound? • What does the term cycling (or recycling) mean? • What do we mean when we say that matter is recycled? • Is food organic or inorganic? Explain the “cycling” of organic matter within living things. • Decay is a process involved in the cycling of matter. Please explain this process. • Using the information in this section make a diagram (or drawing) to show how matter is cycled within an ecosystem. Please use the following terms and organisms in your explanation: plants, inorganic molecules, inorganic nutrients, soil bacteria, fecal matter, rabbit, fox, decomposing bodies. Please ensure that your diagram looks like a cycle. • Please complete Questions 1, 2, 4-6 on page 51.
Chapter 2Cycling of Matter in Ecosystems • Matter – anything that has mass & takes up space • Organic substances contain: • carbon • Hydrogen • Sometimes nitrogen • sometimes oxygen • Example: proteins, sugars, and fats. • Inorganic substances Do not contain the combination of carbon AND hydrogen. Ex: carbon dioxide (CO2), water (H2O) and ammonia (NH3).
Cycling of Organic Matter • Continuously being recycled. • Limited amount of materials found on the Earth means they must be recycled for life to continue. • Example: Carbon molecules are recycled over and over . some part of your body may contain a carbon molecule which was part of a dinosaur over 70 million years ago!
(Eaten by) (Eaten by) (Eaten by) • Plant Rabbit Fox (feces) (Turns it into) (Eaten by) • soil bacteria inorganic molecules plant roots plant
2.2 Pesticides • Pests are organisms considered to be harmful or inconvenient (e.g. weeds, insects, fungi or rodents.)
Why use pesticides? • 30% of the annual crop in Canada is lost to pests (i.e weeds, rusts, moulds, insects, birds and small mammals). This may increase the cost of food. • Malaria (causes fever and can lead to death) is transmitted by a mosquito. • Increases the yield of crops. • Prevents allergies from mold and mildew
First Generation Pesticides • 500 BC sulfur was used to repel insects • 15th century arsenic, lead and mercury were applied to crops as insecticides • 2 Problems: substances killed insects but were also highly poisonous to people AND these pesticides remained in the soil for a long time. • 1763 - gardeners began to use natural plant extracts ( uses the plants’ own chemical defenses) to kill insects.
