Chapter 2 Energy flow and nutrient cycles support life in ecosystems

2.1 Energy Flow in Ecosystems

Why is energy important?

Every living thing uses energy to survive Cell functions Movement Reproduction Building tissues (from wood to muscle)

Reading activity: Text book (58-63) 2.1 Key term chart. Define each term in your own words Give an example for each term.

Bill Nye video food web https://youtu.be/UO7_e9ztf1A?t=1s

2.1 Energy Flow in Ecosystems Biomass is the total mass of all living things in a given area. (measured in g/m2 or kg/m2) Organisms interact with the ecosystem by: Obtaining food from the ecosystem Contributing energy to the ecosystem

Energy Flow in Ecosystems Plants are called producers because they make carbohydrates during photosynthesis. CO2 + H2O + sunlight  C6H12O6 + O2 Consumers get their energy by feeding on producers or other consumers. - Decomposers break-down wastes & dead organisms, through the process of biodegradation.

Producer Consumer Decomposers

Energy Flow & Energy Loss in Ecosystems Methods to represent energy moving through ecosystems. Food chains: show the flow of energy in an ecosystem. Food webs: represent interconnected food chains. They model the feeding relationships in an ecosystem Food pyramids: show the changes in available energy from one trophic level to another in a food chain. They’re also called ecological pyramids

Primary Producer Energy from Sun Primary Consumer Secondary Consumer Tertiary Consumer

Primary Producer Primary Consumer Secondary Consumer Tertiary Consumer First Trophic Level Primary Consumer Second Trophic Level Secondary Consumer Third Trophic Level Tertiary Consumer Fourth Trophic Level

Food Chains Each step is a trophic level Producers = 1st trophic level Primary consumers = 2nd trophic level Secondary consumers = 3rd trophic level Tertiary consumers = 4th trophic level

This dung beetle is a detrivore. Consumers in a food chain can be classified as: Detrivores (decomposers) - obtain energy & nutrients from dead organisms & waste matter. they have their own, separate food chains & they feed on every trophic level. Eg. small insects, earthworms, bacteria & fungi Herbivores - primary consumers eat plants (producers) only Ex. Horse eating hay This dung beetle is a detrivore.

3. Carnivores - secondary or tertiary consumers Secondary consumers eat non-producers (herbivores) Eg. Frog eating a grasshopper Tertiary consumers eat secondary consumers also called top predators, top carnivores or top consumers Eg. Lions eating humans 4. Omnivores - consumers that eat both plants & animals Eg. include humans and bears

Detrivores &Decomposers Energy Flow Within an organism’s niche, the organism interacts with the ecosystem by: -Obtaining food from the ecosystem -Contributing energy to the ecosystem Detrivores &Decomposers

E. Coli

Food Webs Most organisms are part of many food chains. Arrows in a food web represent the flow of energy and nutrients. Following the arrows leads to the top carnivore(s). This food web represents a terrestrial ecosystem that could be found in British Columbia.

Food Pyramids Energy enters at the first tropic level (producers), where there is a large amount of biomass & therefore a lot of energy

It takes large quantities of organisms in one tropic level to meet the energy needs of the next trophic level. 80% - 90% of energy taken in by consumers is used in chemical reactions in the body, or is lost as heat energy.

100kj – 90kj = 10kj 10/100 X 100% = 10% left over

The amount of life an ecosystem can sustain is based on the bottom level of the ecological pyramid, where producers capture energy from the sun.

Lower trophic levels have much larger populations than upper levels. This shows the importance of maintaining large, biodiverse populations at the lowest levels of the food pyramid.

5 Lowest population, biomass and energy Highest population, biomass and energy

Pyramid of Numbers

Biomass Pyramid

Energy Pyramid

RC p64 #1-5 CC P67 #4,5,8,12