Ecosystems

Organization of Life: Ecological niche = the way of life or role of an organism. ex) we tend to live in the same places and eat similar things Abiotic factors = non-living, physical factors of an environment. ex) temperature Biotic factors = living factors of an environment ex) fewer fish → fewer seals → polar bears will go hungry

Organization of Life cont’d…: Organism: A single living thing ex) Ecologists may study feeding, daily movements, or reproduction patterns of polar bears → helps them to understand the ecological niche of the organism in its ecosystem clinical thermometer outdoorthermometer

Organization of Life cont’d…: Population: Number of organisms of the same species living in an ecosystem ex) Ecologists might study the effects of an increasing population of polar bears on the ice-floe ecosystem

Organization of Life cont’d…: Community: All the populations of organisms within an ecosystem ex) Ecologists might study the effects on the community when one of the species becomes extinct

Organization of Life cont’d…: Ecosystem: A system of living things interacting with each other and with the physical world ex) An ecologist might study how changes in snowfall affect the community that lives in the ice-floe ecosystem

Organization of Life cont’d…: Three Ecosystems: Ecosystem Some Populations in the Community

Organization of Life cont’d…: Biome: A collection of related ecosystems ex) Arctic/Polar biome ex) An ecologist might study how climate change affects the ecosystems of the Arctic biome

Organization of Life cont’d…: Biosphere: All the biomes and ecosystems on Earth, from the poles to the equator, from the atmosphere to kilometres into the Earth’s crust Wherever living things are found ex) An ecologist might study how the amount of light coming from the Sun affects the biosphere.

Adaptations for Survival: Plants and animals have special structures and behaviours called adaptations to help them succeed in an ecosystem ex) changing colours, bright colours, disguises

Cycling of Matter and Energy: - Student handouts…

Food Webs:: - Student handouts…

The Carbon Cycle:: Photosynthesis is a two step process: 1) water + light energy → hydrogen + oxygen 2) hydrogen + carbon dioxide → glucose Overall we know = CO2 + H2O → C6H12O6 + O2 Respiration is a process where oxygen is used to break down sugar molecules to release energy. As sugar is broken down, carbon dioxide and water are released sugar + oxygen → carbon dioxide + water

The Carbon Cycle:: Carbon Cycle = the flow of carbon through photosynthesis and respiration Carbon in carbon dioxide from the atmosphere is used to make sugars → plants and animals break down sugars for energy → the breaking down process releases carbon back into the atmosphere Note: Plants also release carbon dioxide because they respire! → During the day, photosynthesis is working faster than respiration so more oxygen is released than carbon dioxide → At night, plants use oxygen and release carbon dioxide as they break down sugar for energy

The Carbon Cycle:: - Student handout…

Pesticides:: Pesticides = chemicals designed to reduce the populations of unwanted organisms, both plant and animal. Remember that for every positive, there is a negative… → mosquitos carry disease (like malaria) → pesticides are used to reduce the mosquito population → losing mosquitos affects the food web/chain Biological Amplification = the increase at each level of a food chain ex) Pesticides stay in the bodies of animals → the concentration of harmful pesticides increases at each level of a food chain → predators have more of these toxic chemicals in their bodies than their prey

The Water Cycle:: Water Beneath Soil: Two sources of fresh water = ground water and surface water Precipitation collecting above ground = surface water ex) lakes, ponds, rivers Surface water filters down into layers of soil and rock → eventually it reaches a level where the soil or rock is saturated with water (this level is called the “water table”) Water at or below the water table = ground water As water seeps downward, it carries dissolved chemicals from the upper to the lower layers of the soil (= “leaching”)

The Water Cycle:: The Water Cycle: Water moves through ecosystems in a cycle. The cycle collects, purifies, and distributes Earth’s water.

Rethinking Before Recycling: Which container is best to hold juice? → tetra box? → aluminum can? → plastic bottle? → glass bottle?

Rethinking Before Recycling: Tetra box = the worst choice for the environment (even though it takes up less room and contains paper which breaks down in a landfill) → although 70% paper, it also contains an aluminum liner and a plastic cover and a liner → the problem is that the aluminum and plastic are recycled using a different process

Rethinking Before Recycling: The Alternatives: Aluminum can is strong → it can be used once and then easily recycled Plastic and glass bottles have the advantage of being reusable → can be used once and then easily recycled

Rethinking Before Recycling: Biodegradable Products: Biodegradable = products (ex. paper) made from things that were once living are broken down easily by decomposers Non-biodegradable = man-made materials (ex. plastic) which do not provide energy for decomposers and do not break down easily

Succession:: Succession = a natural process in which the dominant species in an ecosystem are gradually replaced by others Primary Succession: Occurs in an area where there was no community before Ex) the eruption of an underwater volcano → lava spills above ocean’s surface and a new island forms → within a short time, the island begins to show green (= lichens) Pioneer species = the first organisms to appear in a community ex) lichens

Succession cont’d…: Secondary Succession: Occurs after the partial or complete destruction of a community → the damaged community is replaced by another or by a series of other communities until a stable one is re-established Ex) in a pond...

Succession cont’d…: Ex) in a pond...

Succession cont’d…: Ex) mature forest → destruction by forest fire → pioneer species move in → the forest returns → a young forest - Student handouts…