Presentation on theme: "Brainstorm: What is science? Science is the study (or way of looking at) the natural (or “not made by humans”) world around us. There are many different."— Presentation transcript:
Science is the study (or way of looking at) the natural (or “not made by humans”) world around us. There are many different types of science, including biology (the study of life), chemistry (the study of matter) and physics (the study of matter & energy, and the interaction between them)
An ecosystem includes all organisms in an area that interact with each other and with their environment of energy and matter. In other words, all plants, animals, bacteria, fungus, etc. in an area interact and connect with each other AND with the environment.
Swamps & marshes Freshwater lakes, ponds & streams Saltwater lakes & coastal ocean Temperate forests Highland forests Unit Overview with Youtube Song
The Sun is the ultimate source of energy for most ecosystems Light energy from the Sun is converted by plants into chemical energy Energy is channelled through the food chains
Food chains are often too simplistic and do not provide a completely accurate picture of an ecosystem. A better way to look at the ecosystem is to make use of food pyramids. There are three types of food pyramids: 1.Pyramid of Numbers 2.Pyramid of Biomass 3.Pyramid of Energy (the best!)
Thousands or millions of producers 1-2 top carnivores
A pyramid of numbers shows that in most ecosystems, there are more producers than herbivores (or primary consumers) and more herbivores than carnivores (secondary and teritary consumers). But, this is not true for all ecosystems. Let’s take a look at the ecosystem within a single oak tree:
A pyramid of numbers does not take into account the size of the organism, just the number. A better way of looking at an ecosystem is to use a pyramid of biomass. Biomass means how much mass (or weight) is at each level.
The best type of pyramid is a pyramid of energy. A pyramid of energy flow measures the total amount of food energy that flows through each trophic (or feeding) level. Basically, there is always less energy available for each level as you go UP the pyramid. Also, it is impossible to turn a pyramid of energy upside down.
Probably the most important thing to understand about a food pyramid is that only about 10% of the energy makes it from one level to the next. Why does this happen? Energy is lost because of a variety of reasons, including: 1.Movement 2.Digestion 3.Thinking 4.Growing 5.Reproduction
Check Your Understanding Pg 17; #1-5 OR FINISH FOOD WEBS!!!
Primary productivity is the average amount of new plant material (or biomass) that is added to an ecosystem per year. Primary productivity is measured as the amount of energy per square metre per year (or kJ/m 2 /year) The most productive ecosystems include rain forests and salt marshes, while the least productive would be deserts.
All green plants & seaweed make food using a process called photosynthesis Photosynthesis is a process used by plants to convert (or change) light energy from the sun into sugar. This sugar is used by the plants for energy. These sugars are made from water and carbon dioxide (CO 2 ). Oxygen is released as a waste gas. Photosynthesis provides oxygen to the atmosphere and supplies most of the energy for life on Earth.
A chemical called chlorophyll makes this reaction possible. Chlorophyll gives leaves a green colour. The photosynthesis equation is probably the most important reaction for all life on Earth!!!
These go into the plant cells.These come out of the plant cells.
The MOST PRODUCTIVE ecosystems are salt marshes, swamps and tropical rain forests. The LEAST PRODUCTIVE ecosystems are the tundra, open ocean and deserts.
Read the article Keep in mind that the Sun can only provide the Earth with so much energy. And, the Earth only has so much usable land. BTW, Earth grows 4.2 million hectares of tobacco compared to 3.7 million hectares of tomatoes. Is this a good use of land?
A group of birch trees living on a hill A colony of 2,146 ants All of the spruce trees in a forest All of the cod fish in the Bras d’Or Lake Frogs living in a pond
A population is a group of organisms of the same type (or same species) living in the same area. A population is usually the actual number of individuals in an area that are all the same type.
More births than deaths Moving into an area from somewhere else Lots of food & water No disease Good weather
More deaths than births Moving out of an area Disease & sickness Severe weather, droughts & storms Starvation or lack of food
NO!!! The largest population that an environment can support is called the carrying capacity. For example, a forest ecosystem may only be able support a few dozen deer.
1.Materials & energy (sunlight, water, fertilizer, etc.) 2.Food chains (the amount of food lower in the food chain) 3.Competition (between same species or different species) 4.Overcrowding (leading to not enough space, disease, less births, more deaths, etc.) 5.Natural disasters (such as forest fires, storms)
Natality Mortality Population size Population density Immigration Emigration Intraspecific competition Interspecific competition
1.What is meant by the term “carrying capacity”? 2.How might overcrowding lead to a reduction in population size? 3.How might an increase in population of plants in an area lead to an increase in the population of hawks? 4.How might an increase in the population of hawks in an area lead to an increase in the population of plants?
Work on the activity in class This is an in-class assignment worth 10 points You will be evaluated on how well you work and on getting some good numbers!!
What are nutrients? Nutrients are chemicals used by organisms (plants, animals, fungus, bacteria) to operate their bodies. Nutrients include non-living nutrients (oxygen, water, carbon dioxide, minerals). Organic (or “living nutrients”) include carbohydrates, fats & proteins. What is a nutrient cycle? A nutrient cycle is the cycling (or recycling) or a nutrients through the environment.
What is carbon? Carbon is the key chemical or element upon which all life is based. Carbon is one of the most important chemicals in all living things. What is the carbon cycle? Simply put, plants take in carbon dioxide (CO 2 ) from the air during photosynthesis and make carbohydrates (or sugars). Animals and other consumers then eat the carbohydrates for energy and growth. Also, animals give off carbon dioxide in their breath (as a waste gas). And the cycle continues. Video
1.Plants take in carbon dioxide during a process called photosynthesis. 2.During photosynthesis, plants change carbon dioxide to sugar/carbohydrates and oxygen with the help of sunlight and water. 3.Consumers eat plants (and other animals) for food. These consumers take in sugar/carbohydrates (from plants) during a process called cellular respiration. 4.During cellular respiration, consumers change sugar and oxygen into energy. Carbon dioxide and water are given off as waste products. 5.The cycle repeats. Plants use carbon dioxide during photosynthesis.....
Plants and animals could not live without nitrogen. It is an important part of many cells and processes such as amino acids, proteins, and even our DNA. It is also needed to make chlorophyll in plants, which plants use in photosynthesis to make their food and energy.
Around 78% of the atmosphere is nitrogen. However, this is mostly not usable by animals and plants. Nitrogen is used in fertilizer to help plants grow faster. Nitrous oxide is a greenhouse gas. Too much of it can also cause acid rain. Nitrogen has no color, odor, or taste. It is used in many explosives. About 3% of your body weight is nitrogen.
Nitrogen is used by organisms to carry out many of the functions of life. This element is especially important to plant life. Yet, nitrogen in its gaseous form is almost entirely unusable to organisms. It must first be converted or “fixed” into a more usable form. The process of converting nitrogen is called fixation. There are specialized bacteria whose function it is to fix nitrogen, converting it, so that it can be used by plants. There are still other bacteria who do the reverse. That is, they return nitrogen to is gaseous form. This process is called denitrification. After nitrogen is fixed, it can be absorbed and used by plants, and then eventually by animals. The process of nitrogen being fixed, used by plants and animals, and later returned to the atmosphere is referred to as the nitrogen cycle.
Unfortunately, human activity has altered the cycle. We do this by adding nitrogen into the soil with fertilizer as well as other activities that put more nitrous oxide gas into the atmosphere. This adds in more nitrogen than is needed by normal cycle and upsets the cycle's balance.