1. IGCSE BIOLOGY SECTION 1 LESSON 2

2. Content Section 1 The nature and variety of living organisms a)Characteristics of living organisms b)Variety of living organisms

3. Content Lesson 2 b) Variety of living organisms 1.2 describe the common features shared by organisms within the following main groups: plants, animals, fungi, bacteria, protoctists and viruses, and for each group describe examples and their features as follows (details of life cycle and economic importance are not required) Plants: These are multicellular organisms; their cells contain chloroplasts and are able to carry out photosynthesis; their cells have cellulose cell walls; they store carbohydrates as starch or sucrose Examples include flowering plants, such as a cereal (for example maize), and a herbaceous legume (for example peas or beans) Animals: These are multicellular organisms; their cells do not contain chloroplasts and are not able to carry out photosynthesis; they have no cell walls; they usually have nervous coordination and are able to move from one place to another; they often store carbohydrate as glycogen Examples include mammals (for example humans) and insects (for example housefly and mosquito) Fungi: These are organisms that are not able to carry out photosynthesis; their body is usually organised into a mycelium made from thread-like structures called hyphae, which contain many nuclei; some examples are single-celled; their cells have walls made of chitin; they feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products; this is known as saprotrophic nutrition; they may store carbohydrate as glycogen Examples include Mucor, which has the typical fungal hyphal structure, and yeast, which is single-celled

4. Classification Kingdom Monera (Prokaryotes) Bacteria and Blue-green algae ProtoctistaAmoeba, Paramecium FungiMoulds, Mushrooms, Yeast Plants Algae, ferns and mosses, conifers and flowering plants Animals Jellyfish, worms, arthropods, molluscs, echinoderms, fish, amphibia, reptiles, birds and mammals.

5. Classification Kingdom Monera (Prokaryotes) Bacteria and Blue-green algae ProtoctistaAmoeba, Paramecium FungiMoulds, Mushrooms, Yeast Plants Algae, ferns and mosses, conifers and flowering plants Animals Jellyfish, worms, arthropods, molluscs, echinoderms, fish, amphibia, reptiles, birds and mammals.

6. Plants: These are multicellular organisms; their cells contain chloroplasts and are able to carry out photosynthesis; their cells have cellulose cell walls; they store carbohydrates as starch or sucrose Examples include flowering plants, such as a cereal (for example maize), and a herbaceous legume (for example peas or beans)

7. Examples of flowering plants

8. Maize – a cereal crop

9. Examples of flowering plants Maize – a cereal crop Pea plant – a herbaceous legume

10. Plants are multicellular organisms in that they consist of more than one cell.

11. Advantages to being multicellular include: allows the organism to be larger allows cell differentiation (having different types of cells with different functions) allows the organisms to be more complex.

12. Plants are multicellular organisms in that they consist of more than one cell. Advantages to being multicellular include: allows the organism to be larger allows cell differentiation (having different types of cells with different functions) allows the organisms to be more complex. Multicellular organisms need specialised organ systems to carry out functions such as: photosynthesis (leaves are organs specialised to absorb sunlight). transport (roots are organs specialised to transport water and minerals). reproduction (flowers are organs specialised to produce male and female gametes).

13. Plants are multicellular organisms in that they consist of more than one cell. Advantages to being multicellular include: allows the organism to be larger allows cell differentiation (having different types of cells with different functions) allows the organisms to be more complex. Multicellular organisms need specialised organ systems to carry out functions such as: photosynthesis (leaves are organs specialised to absorb sunlight). transport (roots are organs specialised to transport water and minerals). reproduction (flowers are organs specialised to produce male and female gametes). Plants are autotrophs – this means that they are able to produce their own food using sunlight energy = PHOTOSYNTHESIS

20. Examples of flowering plants Maize – a cereal crop Maize is also known as corn (corn on the cob). It is a cereal crop

21. Examples of flowering plants Maize – a cereal crop Maize is also known as corn (corn on the cob). It is a cereal crop Cereal crop – a grass such as wheat, oats, or corn, the starchy grains of which are used as food

22. Examples of flowering plants Maize – a cereal crop Maize is also known as corn (corn on the cob). It is a cereal crop that originated in South America, but is now grown around the world. Different varieties of maize yield cornmeal, cornflour, sweetcorn and popcorn.

23. Examples of flowering plants Maize – a cereal crop Maize is also known as corn (corn on the cob). It is a cereal crop that originated in South America, but is now grown around the world. Different varieties of maize yield cornmeal, cornflour, sweetcorn and popcorn. Photosynthesis in maize is a little different to other plants. Maize is known as a C4 plant because the pathway is different but more effective.

24. Examples of flowering plants Pea plant – a herbaceous legume Peas belong to a group of plants known as legumes.

25. Examples of flowering plants Pea plant – a herbaceous legume Peas belong to a group of plants known as legumes. Many legumes, including peas contain symbiotic bacteria

26. Examples of flowering plants Pea plant – a herbaceous legume Peas belong to a group of plants known as legumes. Many legumes, including peas contain symbiotic bacteria Symbiotic bacteria – bacteria living with other organisms to mutual benefit

27. Examples of flowering plants Pea plant – a herbaceous legume Peas belong to a group of plants known as legumes. Many legumes, including peas contain symbiotic bacteria. These bacteria live in root nodules and have the ability to fix atmospheric nitrogen.

28. Examples of flowering plants Pea plant – a herbaceous legume Peas belong to a group of plants known as legumes. Many legumes, including peas contain symbiotic bacteria. These bacteria live in root nodules and have the ability to fix atmospheric nitrogen. en.wikiperdia.org

29. Animals: These are multicellular organisms; their cells do not contain chloroplasts and are not able to carry out photosynthesis; they have no cell walls; they usually have nervous coordination and are able to move from one place to another; they often store carbohydrate as glycogen. Examples include mammals (for example humans) and insects (for example housefly and mosquito)

30. Examples of animals

31. Mammals eg. humans

32. Examples of animals Mammals eg. humans Insects eg. housefly and mosquito

33. Examples of animals Mammals eg. humans Insects eg. housefly and mosquito Animals are multicellular organisms in that they consist of more than one cell.

34. Examples of animals Mammals eg. humans Insects eg. housefly and mosquito Animals are multicellular organisms in that they consist of more than one cell. Animals are heterotrophs – they cannot manufacture their own food, but have to consume ready-made organic molecules

35. Animal cells differ from plant cells in that they do not have chloroplasts (so cannot photosynthesise) and do not have cellulose cell walls.

37. Animals usually have organs and organ systems. The nervous system is an example of an organ system, and enables communication between cells.

40. Through co-ordination of the nervous and muscular systems animals are able to physically move from one place to another.

41. Feeding – animals store carbohydrates as glycogen

42. Mosquitoes have tubular mouthparts that are adapted for piercing the skin and sucking blood from the skin capillaries

43. Feeding – animals store carbohydrates as glycogen Mosquitoes have tubular mouthparts that are adapted for piercing the skin and sucking blood from the skin capillaries

44. Fungi: These are organisms that are not able to carry out photosynthesis; their body is usually organised into a mycelium made from thread-like structures called hyphae, which contain many nuclei; some examples are single-celled; their cells have walls made of chitin; they feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products; this is known as saprotrophic nutrition; they may store carbohydrate as glycogen. Examples include Mucor, which has the typical fungal hyphal structure, and yeast, which is single-celled

45. Examples of fungi

46. en.wikiperdia.org sciencedaily.com Toadstools Mucor (bread mold) Yeast

47. Examples of fungi en.wikiperdia.org Hyphae – thread-like branching structures which make up the main body (or mycelium) of a multicellular fungus. Sporangia – pin-like structures that project upwards from the mycelium. They contain the spores (the reproductive cells)

48. Fungi do not have chlorophyll, so are unable to photosynthesise.

49. Most fungi are saprotrophs – they live on dead organic matter.

50. Fungi do not have chlorophyll, so are unable to photosynthesise. Most fungi are saprotrophs – they live on dead organic matter. en.wikiperdia.org The hyphae secrete enzymes into the organic material (eg. bread) and digest it to liquid products. The digested products are then absorbed back into the hyphae and used for respiration or growth.

51. Summary - comparisons

52. PlantsAnimalsFungi Example Cell type Cell structure Nutrition Other features

53. Summary - comparisons PlantsAnimalsFungi Example Cell type Cell structure Nutrition Other features

54. Summary - comparisons PlantsAnimalsFungi Example Cell type Multicellular Multicellular, unicellular Cell structure Nutrition Other features

55. Summary - comparisons PlantsAnimalsFungi Example Cell type Multicellular Multicellular, unicellular Cell structure Cellulose cell wall, contain chloroplasts No chloroplasts or cell walls Thread-like hyphae that contain nuclei Nutrition Other features

56. Summary - comparisons PlantsAnimalsFungi Example Cell type Multicellular Multicellular, unicellular Cell structure Cellulose cell wall, contain chloroplasts No chloroplasts or cell walls Thread-like hyphae that contain nuclei Nutrition Autotrophs – make food by photosynthesis Heterotrophs – consume ready- made food Saprotrophs – feed on dead organic matter Other features

57. Summary - comparisons PlantsAnimalsFungi Example Cell type Multicellular Multicellular, unicellular Cell structure Cellulose cell wall, contain chloroplasts No chloroplasts or cell walls Thread-like hyphae that contain nuclei Nutrition Autotrophs – make food by photosynthesis Heterotrophs – consume ready- made food Saprotrophs – feed on dead organic matter Other features Store carbohydrates as starch Store carbohydrates as glycogen

58. End of Section 1 Lesson 2 In this lesson we have covered: Outline of the plant kingdom Outline of the animal kingdom Outline of the fungi kingdom