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

Food chains show how food passes from one living thing to another

All food chains start with a Plant Plants can make their own food, using sunlight

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

Food chains and food webs work in the same way in the sea... … but the plants and animals look a bit different!

Out in the ocean, there is no grass or trees The plants are tiny ALGAE - you need a microscope to see them ALGAE Microscopic plants - make their own food COPEPOD A tiny animal that eats plants FISH An animal that eats other animals This is a food chain in the ocean

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

The food chain won’t stop there...

In most habitats, there are several food chains These are linked together to form a Food Web

Food webs can be quite complicated Here is one from the ocean around Antarctica …

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 This food web contains 7 types of living things, and 9 food chains

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

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

Not all energy from food is turned into tissue ‘growth’ A lot of food energy is used to provide energy for heat, warmth, cellular respiration… Some is indigestible, and is ‘lost’ (e.g. cellulose, teeth, claws, skin…)

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’

The rate at which animals grow is often related to their body size

GRASS RABBIT FOX On land, herbivores and predators are often similar in size

In the oceans, both the plants and the herbivores are small. There are great size differences between herbivores and predators We can understand the size differences more easily if we match each living thing to familiar objects. Here, we magnify each 1000 times Making each alga cell 1000 times bigger means that it is about the size of a squash ball Making the krill 1000 times bigger means that it becomes as long as a small bus Making the whale 1000 times bigger means that it is still huge - it would stretch across the Isle of Wight

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

The shortest food chain in the Antarctic food web has two links

LOSS

For 100 TONNES of algal growth… You get 15 tons of new krill growth And only 600 kg of new whale growth

The longest food chain in the Antarctic food web has five links

LOSS

Now, for 100 tonnes of algal growth There is 1 kg of seal growth Which means that % of the energy of the algae eaten by the copepods has been ‘lost’

In the food chain with more links, more producer growth is lost

A food chain links plants and animals in a habitat All food chains start with a plant = producer You have seen that -

Food webs on land and in the ocean are similar In the ocean, plants and herbivores are small You have seen that -

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 -