What is the Biosphere ?

1. Ecology is the study of the interactions between living things and between organisms and their environment. Their environment refers to all the conditions in which the organism lives, which affect the growth and development of the organism.

2. What is the Biosphere? The biosphere is that part of the earth inhabited by living organisms, including land, ocean and the atmosphere in which life can exist.

3. Biosphere

4. What is an Ecosystem? An ecosystem is a community of living organisms interacting with one another and their non-living environment within a particular area. Ecosystem = Communities + Environment Note: ecology is the study of ecosystems

5. Examples of ecosystems Woodland Hedgerow Seashore Marine Grassland Freshwater Tree, etc. Can you name some more?

6. To study an ecosystem We divide the ecosystem into a number of smaller, more manageable areas - habitats. Habitat: area where an organism or group of organisms live.

7. More Definitions Population: all the members of the same species living in an area e.g. a population of frogs in a pond. Community: a group of plants and animals which share resources of a particular habitat. The resources they share would include: water shelter space light food

8. Environmental factors that affect organisms Abiotic Biotic Climatic Edaphic *Aquatic

9. Abiotic Factors Abioticare non-living factors • Temperature • Light intensity • Air speed • Water current • Humidity • pH • Dissolved oxygen • Salinity • Nitrate, phosphate and other • plant nutrients

10. Abiotic factors in a woodland

11. Biotic factors Bioticare living factors • Plants for food and shelter • Predators • Prey • Parasites and pathogens • Decomposers • Competitors • Pollinators

12. Climatic factors Climaticare the average weather conditions that affect the community in an ecosystem. • Temperature • Rainfall • Humidity • Wind • Light intensity (including seasonal variations) • Day length

13. Edaphic Factors Edaphicfactors: soil factors associated with: • Soil type, • Soil pH, • Available (soil) water, • Air and Mineral content, • Humus, • Soil texture and Structure.

14. Aquatic Environmental Factors Aquatic environments have special factors that influence them: • Light penetration • Currents • Wave action

15. Energy Flow Ecosystems are unable to function unless there is a constant input of energy from an external source. Where does this energy come from? The Sun

16. The Sun The sun is the primary source of energy for our planet.

17. Energy Flow Feeding allows energy to flow from one organism to another in an ecosystem. • All living things require energy, in order to live. • Plants receive this energy from the sun, using this • solar energy and chlorophyll by a process of • photosynthesis they make their own food. • Because they can make their own food (autotrophic) • plants are called producers

18. Energy Flow • All other organisms in the ecosystem either • directly or indirectly obtain their energy from • green plants. • Organisms that feed directly from green plants • are called primary consumers • Herbivores and decomposers are examples of primary consumers

19. Energy Flow • If the organisms feed on dead animal remains • they belong to secondary consumers (carnivores) • The feeding relationship between organisms in • which energy is transferred is called a food chain. • The food chain must always start with a primary • producer i.e. a plant

20. Energy Flow in an Ecosystem Is the pathway of energy transfer from one organism to the next in an ecosystem due to feeding, e.g. along a food chain

21. Food Chain Is a flow diagram that begins with a plant and shows how food/energy is passed through a series of organisms in a community. Each organism feeds on the one before it. A food chain ends when there is not enough energy to support another organism. An example of a food chain: grass rabbit  fox.

22. Woodland Food Chain Honeysuckle  aphids  ladybirds  thrushes Primary consumer Secondary consumer Tertiary consumer Producer

23. A Grazing food chain • is a sequence of organisms in which each one is eaten • by the next member in the chain. • the initial plant is living. Grass  grasshoppers  frogs  hawks Seaweed  winkles  crabs  herring gulls Phytoplankton  zooplankton  copepod  herring

24. Grazing Food Chains

25. Trophic Level The trophic level is the position of an organism in a food chain. At each trophic level about 90% of the received energy is lost to the environment as a result of respiration and only 10% of it is retained for the next level. • Plants are at the 1st trophic level (T1) • Herbivores occupy the 2nd trophic level (T2) • Carnivores (eat herbivores) are at the 3rd trophic level • (T3). • 4th trophic level (T4) is often occupied by the top • carnivore.

26. Trophic Level

27. Trophic Level

28. Food Chain • The size of the animal increases as you go along the chain – this is because each animal tends to feed on something smaller than itself. • The numbers of individuals at each level decreases – there will be far more grass plants in a field than there will be rabbits. • The relationship between the number of individuals at the different levels is usually represented as a pyramid of numbers

29. Pyramid of Numbers • A diagram that represents the numbers of organisms at each trophic level in a food chain. • Bottom layer is the largest and represents a very large number of primary producers • The next layer smaller and represents a smaller number of primary consumers • The next layer – the no. of secondary consumers • The uppermost layer where there may be only one tertiary consumer

30. Pyramid of Numbers

31. Pyramids of Numbers • Types of Pyramids: • Normal • Distorted • Inverted

32. Distorted Pyramid of Numbers

33. Inverted Pyramid of Numbers

34. Food Web This is a chart showing all the feeding connections in the habitat/ecosystem. Constructed by showing the links between all the interconnecting food chains in the habitat.

35. Food Web the interconnected food chains in an ecosystem e.g.

36. Seashore Food Web

37. Food Niche A niche is the functional role of an organism in an ecosystem. A food niche refers to the feeding role of an organism in a habitat. Predators: are specialised to find and kill their prey e.g. fox Parasites: are specialised to feed in or on the host e.g. liverfluke, fleas

38. Nutrient Recycling There is a limited amount of nutrients on earth e.g. you are probably aware of the water cycle – where water is constantly being recycled in nature. There are similar cycles for all nutrients. When plants and animals die, their nutrient content is not wasted. Bacteria and fungi decompose the remains and release the nutrients back into the abiotic environment (i.e. into the soil, nearby water and air).

39. Nutrient Recycling These nutrients are then taken up by other plants and used to make new organic material. This material is passed on down the food chains and is reused by all the chain members. When death occurs for these members, the nutrients are again returned to the abiotic environment and the cycling of nutrients continues in this circular way.

40. Recycling nutrients within an ecosystem

41. Nutrient Recycling Nutrient recycling is the way in which elements are continuously being broken down and/or exchanged for reuse between the living and non-living components of an ecosystem. While many nutrients are recycled we will focus on two in particular: • Carbon • Nitrogen

42. The Carbon Cycle • The carbon cycle is the way in which carbon is taken • from and added back to the environment. • Three groups of organisms are involved in the carbon • cycle: • 1. Plants • 2. Animals • 3. Micro-organisms

43. The Carbon Cycle Role of organisms in the carbon cycle: Plants: - remove carbon from the environment in photosynthesis and return it in respiration. Animals: - obtain carbon by eating plants and release it in the form of CO2 in respiration. Micro-organisms: - fungi and bacteria return carbon to the environment when they decompose dead plants and animals.

44. The Carbon Cycle

45. The Nitrogen Cycle • All organisms need nitrogen for protein, DNA & RNA • manufacture • 78% of the Earth’s atmosphere is nitrogen gas, but it • cannot be used in this form by plants and animals. • Nitrogen gas must first be ‘fixed’, i.e. changed to a • suitable form (ammonia or nitrate) before it can be used.

46. The Nitrogen Cycle During the nitrogen cycle the following processes occur: A – nitrogen fixation B – assimilation C – decomposition D – nitrification E – denitrification

47. The Nitrogen Cycle

48. The Nitrogen Cycle A. Nitrogen Fixation: is the conversion of nitrogen gas into ammonia (NH3), ammonium (NH4+), nitrate (NO3-) carried out by volcanic action, lightning, industrial processes and some bacteria. B. Assimilation: nitrates are converted into plant and animal protein, DNA and RNA. C. Decomposition: this process is carried out by bacteria and fungi of decay which as a result release nitrogenous compounds such as ammonia (NH3) into the soil.

49. The Nitrogen Cycle D. Nitrification: - is the conversion of ammonia and ammonium compounds to nitrite and then to nitrate. - carried out by nitrifying bacteria. E. Denitrification: - is the conversion of nitrates to nitrogen gas. - carried out by denitrifying bacteria

50. Role of Organisms in the Nitrogen Cycle Bacteria very important role in nitrogen cycle. Four types: Nitrogen fixing bacteria: convert nitrogen gas into ammonia or nitrates. Decomposing bacteria: convert decaying nitrogen waste to ammonia. Nitrifying bacteria: convert ammonia to nitrites then nitrates. Denitrifying bacteria: convert nitrates to nitrogen gas.