Chapter 2.5 Food Webs and Ecological Pyramids https://www.youtube.com/watch?v=hIy0ZlyPPDg

Ecological Niche Ecological Niche – the role a species serves in its ecosystem including what it eats, what eats it, and how it behaves No 2 species have the same ecological niche

Example: Black Bear Example: a black bear’s ecological niche – it eats plants/berries/nuts/small animals, hibernate in the winter, have few predators, insects feed on them What’s your ecological niche?

Feeding Roles Herbivore – animal that eats plants/producers Carnivore – animal that eats other animals Omnivore – animals that eats plants and animals Scavenger – animal that feeds on the remains of another organism

Food Chains The most common interactions between species is their feeding relationship Food Chain – a sequence of organisms, feeding on the next, transferring energy

Trophic Levels Trophic Level – a way to describe the level of an organism, depending on where it is in the food chain Producers are always the 1st trophic level (the lowest) Herbivores are always the 2nd trophic level (they eat the producer) Carnivores occupy 3rd, 4th, 5th, etc

Food Webs Food chains don’t exist in nature…food webs do Food Web - the feeding relationships within a community Very complex An interconnecting set of food chains Stable Arrows always point to what eats it

Practice Write down as man food chains as you see in this food web Now, label their tropic levels

Food webs help us figure out what happens if a species is removed or added to an ecosystem

Ecological Pyramids Ecological Pyramids – a way to display the relationship between trophic levels There are 3 types of pyramids: energy pyramids, numbers pyramids, and biomass pyramids

1. Energy Pyramid Illustrates the energy loss and transfer between levels A very small amount of energy gets passed on to the next trophic level (only 10%) This energy is used/wasted on growing, breathing, reproduction, heat loss, etc

2. Numbers Pyramid A representation of how many (#) of a certain species are present Usually, the 2nd level is the biggest

3. Biomass Pyramid Because less energy gets passed on to the top of the food chain, there are so many less predators at the top of the food chain Example: what is there more of…grass or hawks? Biomass - the total mass (kg) of all organisms in the trophic level in a given area Species at lower parts of the food chain have more energy

Homework Page 47 # 1, 3, 4, 7, 8 https://www.youtube.com/watch?v=MGODmyXkkPU https://www.youtube.com/watch?v=ScizkxMlEOM https://www.youtube.com/watch?v=qUZkWZ12A8s