Welcome to Ecology

What is Ecology? Welcome to the Anthropocene…

Inquiry Activity In groups of 2-3, you have five minutes to make a list of all of the types of organisms, including plants, humans, animals, insects etc that you have seen in a specific location. Rainforest Tundra!

Inquiry Activity Make a diagram that shows how the organisms that you listed interact with each other. Who eats who/what? Where do these organisms live?

Think About It 1. Which organisms on your list provide energy or nutrients to the others? 2. What would you expect to happen if all the plants in your diagram died? EXPLAIN your answer. 3. Why is it difficult to make accurate predictions about changes in communities of organisms?

1. Ecology Definitions

3.1: What is ecology? Ecology is the scientific study of interactions among organisms and between organisms and their environment Etymology (word Root) : eco comes from the Greek oikos which means house.

The Biosphere The biosphere contains the combined portions of the Earth in which all life exists, including land, water and air or atmosphere. It extends 8 km above the Earth’s surface and as far as 11 km below the surface of the ocean.

Within the Biosphere are levels of organization

1. Ecology Definitions: Feeding relationships

Autotrophs/ Producers/ (Trophic Level 1) Food energy is most commonly produced from light energy through photosynthesis Some autotrophs can produce food energy without light, instead using chemicals like hydrogen sulfide. These autotrophs use a process called chemiosynthesis.

Chemotrophs Some autotrophs can produce food energy without light, instead they use chemicals like hydrogen sulfide. These autotrophs use a process called chemiosynthesis. Let’s meet some… Deep Sea Challenger Compare chemosynthesis with photosynthesis Giant Amoeba

Heterotrophs/ Consumers (and decomposers) Organisms that rely on other organisms for food are called heterotrophs or consumers.

Decomposers can be detrivores or saprotrophs detritus 1 detritus 2 Decomposers (bacteria and fungi) recycle nutrients (organic matter and other essential elements) in an ecosystem

3. Feeding relationship: Food webs and food chains

Where does all of your energy originally come from? What about other essential ‘nutrients’ (e.g. iron, nitrogen, water, calcium)…

Sometimes food chains are described using ‘trophic levels’

All food chains start with a PRODUCER (an organism that can make its own energy store, usually by photosynthesis): Plant (or, in the ocean, plankton or photosynthetic algae) Food chains show how food passes from one living thing to another

GRASS A plant - makes its own food RABBIT An animal that eats plants FOX An animal that eats other animals The arrows show the food chain

GRASS A plant - makes its own food RABBIT An animal that eats plants FOX An animal that eats other animals The plant is a ‘producer’ PRODUCER

GRASS A plant - makes its own food RABBIT An animal that eats plants FOX An animal that eats other animals The rabbit is a ‘consumer’ - a herbivore or plant-eater PRODUCERCONSUMER

GRASS A plant - makes its own food RABBIT An animal that eats plants FOX An animal that eats other animals The fox is also a ‘consumer’ - a predator or meat- eater PRODUCERCONSUMER

Out in the ocean, there is no grass or trees PRODUCERCONSUMER ALGAE COPEPOD FISH

Most food in a food chain is turned into energy and lost Long food chains waste more food than short ones You have seen that -

Not all energy from food is turned into tissue ‘growth’ A lot of food energy is used to provide energy for heat, warmth, movement, reproduction, cellular respiration… Some is indigestible, and is ‘lost’ (pooped out!) (e.g. cellulose, teeth, claws, skin…) This happens at EACH LINK in the food chain…

An example: krill feeding on algae 70 grammes of algae eaten per day 10 grammes - about 15% - is indigestible 50 grammes of food are used to provide energy for swimming and catching more food This leaves 10 grammes of food that can be used for growth

70 grammes ‘in’ = 100% 50 grammes plus 10 grammes ‘to waste’ = 85% of food eaten 10 grammes to growth = 15% of food eaten

The same thing happens at every step along the food chain Look at the food web from Antarctica...

A large blue whale will eat 3 tonnes of krill each day The amount of growth will be 120 kilogrammes -96% of the food has ‘gone to waste’

In most habitats, there are several food chains linked together into a food web…

A simple food chain - whale eats krill eats algae Copepods also eat algae, and are eaten by krill Fish eat krill and copepods Squid eat fish and krill Seals eat squid and fish How many food chains can you decipher here?

Some questions about your food web… 1.Can you make any connections on your diagram that aren’t a feeding relationship? (For example, bryozoans provide a nursery habitat for young fish.) 2.Are some organisms more important than others? 3.Why are decomposers important in a food web? 4.Do you think anything is missing from your food web? 5.Where do humans fit in the marine food web?

Some scenarios related to your fod web… Group 1: A large commercial fishing company triples their annual catch of red cod in the area. Group 2: The land on the edge of the estuary is converted to intensive farming. There is a big increase in agricultural run-off and nutrients into the estuary. This increases the risk of phytoplankton blooms. Group 3: Due to increased carbon emissions, the ocean is becoming more acidic. Bryozoans and other shelled animals will no longer be able to make shells.

Food webs can tell us much more than ‘who’s eating who’….

Are food webs useful??

Are food webs useful?

1. Ecology Definitions: Pyramids of energy/ biomass/ numbers

We use THREE ecological pyramids to try to understand ‘energy’ and nutrient interactions in ecosystems… 1.Pyramid of ENERGY 2.Pyramid of BIOMASS 3.Pyramid of NUMBERS

We often use BIOMASS in order to evaluate changes in energy in food chains/webs

Some things we have learned recently about energy pyramids…(1) Sometimes we don’t understand them!

Funnily enough, in a healthy ocean, marine food pyramids are INVERTED!... And this is why…

Some new things we have learned about food webs/ energy pyramids (2): TROPHIC CASCADES…

Tropic cascades… Trophic cascades are powerful indirect interactions that can control entire ecosystems. Trophic cascades occur when predators limit the density and/or behavior of their prey and thereby enhance survival of the next lower trophic level.