Ecosystems & Relationships Between Organisms + Physical Factors Affecting Organisms

Life Science

The Food Web

interconnected energy systems; demonstrates the alternate energy links available to an organism

ie food chains

What are the 5 levels of the food web?

producer → primary consumer → secondary consumer → tertiary consumer —> decomposers

Producer

green plants in the ecosystem that get their energy directly from the sun (ie photosynthesis)

Primary Consumer

herbivores, eat producer (ie insects & elephants)

Secondary Consumer

eats primary consumer; carnivores

Tertiary Consumer

feed on primary & secondary consumers

Decomposers

consume dead organisms, therefore carrying out natural process of decomposition

ie bacteria & fungi

Heterotrophic

decomposers, herbivores and predators are heterotrophic, meaning they cannot produce their own foods, instead they take nutrition from other sources, mainly plant or animal matter

What is the energy pyramid based on and what are the different levels?

how much energy is available to each category

producers (biggest level since they get energy from the sun) —> primary —> secondary —> tertiary

What determines the types of organisms an ecosystem can support?

primarily determined by the amount of water, which is the most important factor in determining the distribution of plant life

What is a Symbiotic Relationship and what are the 3 categories?

organisms live in a close interaction with one another.

Mutualism, Parasitism, Commensalism

Mutualism

both members benefit

ex: acacia tree + stinging insect: the insect stings animals that try to eat the tree, in turn the tree provides a home for the insect

Parasitism

one member benefits, the other is harmed

ex: a tapeworm living in and feeding on the intestines of animals

Commensalism

one member benefits, the other is unaffected

ex: fish that ride on whales and sharks and feed on scraps they leave behind. fish get transport and food! the shark and whale are unaffected

Predation is…

a non-symbiotic relationship in which a predator hunts prey

Climate Change

climate change has a major impact on ecosystems. climate is affected by natural processes, as well as human activities

What is an example of a global impact and a local impact of climate change?

global: ocean acidity

local: heat waves

How can climate change be reduced?

home energy efficiency (ie turning off lights, not too much heat or AC), supporting clean power production, green transportation, local/low-animal food choices, reducing/reusing/recycling, forest conservation & land management.

Osmosis

causes salt to move across a permeable membrane from an area of greater salinity to an area of lesser salinity, which causes water to move from area of lesser salinity to greater salinity, until ratio of salt to water is the same on both sides

Why cant humans drink salt water?

because of osmosis

there is more salt in the water than in your body, therefore the water would get sucked out of the cells by salt

What would happen if you put blue dye and salt in a pot of clean water with a cut white rose inside it?

the flower will wilt, but not turn blue, because no water is going up through stem, water is coming down to the salty area.

What factors affect plant growth?

gravity, light and stress

how does gravity affect plant growth?

geotropism, which is a response to gravity, the root gets sent down into soil and the stem gets sent up away from gravity

how does light affect plant growth?

phototropism - growth is now based on light

ie house plants leaning towards windows where light is hitting

how does stress affect plant growth?

can inhibit growth or cause plant to die

ie: a frost making the plant freeze, someone stepping on it, etc.