IB Biology
Chris McDermut
4.1.1-4.1.5 Communities and
Ecosystems
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•4.1.1 Define ecology, ecosystem, population, community, species, habitat (1092-1094)
– Ecology: The study of relationships between organisms and their environment
– Ecosystem: A community and its abiotic environment
– Population: A group of organisms of the same species who live in the same area at the same time
– Community: A group of populations living and interacting with each other in an area
– Species: A group of organisms which can interbreed and produce fertile offspring
– Habitat: The environment in which a species normally lives of the location of a living organism
•4.1.2 Explain how the biosphere consists of interdependent and interrelated ecosystems (1092-1094)
-The biosphere consists of interdependent and interrelated ecosystems: rainforests, rivers, oceans, creeks,
deserts, etc.
•4.1.3 Define autotrophs (producers), heterotrophs (consumers), detrivore, and saprotrophs (decomposers)
(176-177, 1198-1199)
-Autotroph:An organism that makes its own food
-Heterotroph: An organism that obtains its food from another organism
-Detrivore: and organism that feeds on dead organic matter by ingesting it
-Saprotroph: an organism that feeds on dead organic matter by secreting digestive enzymes into it and feeds on
the products
•4.1.4 Describe what is meant by a food chain, give three examples (1181)
-a food chain is the interrelation of individuals to each other
-ex1: phytoplankton, zooplankton, minnow, needle fish, osprey
-ex2: grass, mouse, cobra, mongoose
-ex3: grass, rabbit, fox, bear
•4.1.5 Describe what is meant by a foodweb (1182)
-A diagram that shows all the feeding relationships in a community
4.1.1-4.1.5 Communities and
Ecosystems Visuals
4.1.6-4.1.12 Communities and
Ecosystems
•4.1.6 Define trophic level (1181)
-trophic level: position in the food chain
•4.1.7 Define the tropihc level of organisms in a food chain and a food web (1181)
-Producer, primary consumer, secondary consumer, tertiary consumer, quarternary consumer
•4.1.8 Construct a food web with at least ten organisms (1182)
-see images on next slide
•4.1.9 State that light is the initial energy source for all most all living things (1199)
-light provides the energy source for autotrophs (producers), which provides the energy for all following consumers
•4.1.10 Explain the energy flow in a food chain (1181, 1199)
-light captured by plants in converted into chemical energy
-energy in plant tissues is passed to the next trophic level for cell respiration
-organic matter containing stored energy can be eaten by a second consumer
• 4.1.11 State that when energy transformations takes place, including those in living organisms, the process is never 100% efficient,
usually 10-20% (1206-1207)
-The energy transformation process is never 100% efficient
•4.1.12 Explain what is meant by the pyramid of energy and the reasons for its shape (1206-1207)
-a pyramid of energy shows the flow of energy from one trophic level to the next in a community. The units of a pyramid of energy are
energy per unit and per unit time.
-the pyramid becomes smaller as it gets taller because not all energy is being transferred
-some organisms die before an organism in the next level eats them
-some parts of organisms such as bones or hair are not eaten
-some parts of the organism are indegestible and pass out as feces
-much energy is absorbed by an organism in cell respiration. The energy is then used in energy transformations within the body,
with also lose energy because they are not 100% efficient.
4.1.6-4.1.12 Communities and
Ecosystems Visuals
4.1.13-4.1.15 Communities and
Ecosystems
•4.1.12 Explain that energy can enter and leave ad ecosystem, but nutrients must be recycled (1208-1214)
-nutrients are recycled by saprotrophs and detrivores
•4.1.14 Draw the carbon cycle to show the processes involved (1211)
-see images on next slide
•4.1.15 Explain the role of saprotrophic bacteria and fungi in recycling nutrients (1208-1214)
-their enzymes break up complex compounds and free nutrients
4.1.13-4.1.15 Communities and
Ecosystems Visuals
Vocabulary
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-ecology
-ecosytem-interdependent and interrelated
-population
-community
-biosphere
-species
-habitat
-autotroph
-heterotroph
-detrivore
Saprotroph
-food chain
-trophic level
-pyramid of energy
-carbon cycle