Introduction to Biodiversity

1. Introduction to Biodiversity ASAB – NUST Fall 2012

2. The variety of life is biological diversity.

3. Use of the term “biological diversity” in its current sense began in 1980.

4. Biodiversity = biological diversity Coined in 1985 for a conference, the proceedings of which were published as the book “Biodiversity”edited by E. O. Wilson.

5. What does it mean? The variability among living organisms from all sources including terrestrial and aquatic systems and the ecological complexes of which they are a part; diversity within species, among species, and of ecosystems; interactions at all levels among organisms.

6. From Frankel et al., 1995, The conservation of plant biodiversity.

7. Fundamental levels of organization • Genetic • Organismal • Ecological

8. Ecological Diversity • Communities of species, their interactions • Communities + resources (energy, nutrients, etc.) = ecosystem • Measured primarily in terms of vegetation but relative abundance of species also important • No unique definition and classification at the global level

9. Organismal Diversity • Individuals, species • Mostly measured by numbers of species • Estimated 1.7 million species described to date • Estimated total number ranges from 2 to 50 million (up to 100 million) species • Mostly microorganisms and insects

10. Genetic diversity • Heritable variation within and between populations of organisms • Encoded in the sequence of 4 base-pairs that make up DNA • Arises by mutations in genes and chromosomes • Very small fraction of genetic diversity is outwardly expressed

11. Why care about what we can’t see? • Genetic variation enables evolutionary change and artificial selection • Estimated 109 different genes across the Earth’s biota • Represents a largely untapped genetic library

12. Ecosystems

13. Scale of relationships Molecules smallest Genes Cells Organisms (individuals) Populations Species Communities Ecosystems Biomes Biosphere largest

14. Ecological Principles • Everything is connected to everything else. • Everything has to go somewhere. • There is no free lunch in nature. (Or, you don’t get something for nothing.)

15. Communities Community: all of the organisms in a given area (habitat) and their interactions.

16. Ecosystems Ecosystem = biotic community + abiotic environment Energy from the sun Precipitation, etc. e.g., flower + pollinator Nutrients such as carbon, etc.

17. Ecosystems The scale can be… very small (a leaf) to very large (global)

18. Ecosystems Energy flow is one-way through ecosystems. Materials (nutrients) are cycled through ecosystems.

19. Ecosystems—1) Energy processes Photosynthesis Respiration

20. Ecosystems—1) Energy processes Photosynthesis transforms radiant (solar) energy into chemical energy (stored as chemical bonds in sugars and carbohydrates. O2 CO2 plant sun sugars, starches in cells

21. Ecosystems—1) Energy processes Respiration is a step-by-step process that allows organisms to use the energy stored the chemical bonds manufactured during photosynthesis. O2 energy for cellular work + heat sugars, starches

22. Ecosystems—2) energy users • There are three main categories of organisms • according to the ecological roles they play: • Producers (primary producers, autotrophs) • Consumers (heterotrophs) • 3) Decomposers (a special type of consumer)

23. Ecosystems—2) energy users Producers capture the sun’s energy and transform it into chemical energy through photosynthesis. plants + algae + blue-green algae

24. Ecosystems—2) energy users Consumers are organisms that eat other organisms. Herbivores eat producers directly, carnivores eat other consumers. Examples: panda eating bamboo, bird eating nectar or flowers snail grazing on algae Herbivores (grazers, primary consumers)

25. Ecosystems—2) energy users Consumers are organisms that eat other organisms. Herbivores eat producers directly, carnivores eat other consumers. Examples: limpkin eating apple snails American alligator amoeba Carnivores (secondary or tertiary consumers)

26. Ecosystems—2) energy users Decomposers (detritivores) are a type of consumer that feed on dead organic matter—they can obtain this from any of the other trophic levels. fungi and many bacteria but also scavengers such as vultures

27. Ecosystems—3) Energy flow Energy flow is one-way through ecosystems. WHY?

28. Ecosystems—3) Energy flow In any energy transformation (e.g., from one trophic level* to another) there is a net loss of usable energy. *Trophic level: feeding relationships, who is eating whom.

29. Ecosystems—3) Energy flow Lost as heat decomposer decomposer decomposer cow jaguar sun plant Lost as heat

30. Ecosystems—3) Energy flow Lost as heat decomposer decomposer decomposer 90% 90% 90% 10% 10% 10% 10% 10% 1-5% sun cow plant jaguar captured 90% 90% Lost as heat

31. Ecosystems—3) Energy flow Carnivores, especially secondary or tertiary ones, are rare. carnivores herbivores producers

32. Ecosystems—Materials Water and elements (e.g., carbon, nitrogen) and other materials are cycled through ecosystems. They move between organic and inorganic phases by both biotic and abiotic processes. The diversity of microorganisms (especially bacteria) controls key steps in various cycles (see textbook examples of the nitrogen cycle, the carbon cycle, etc.)

33. Ecosystem Services • Services provided by biodiversity that keep ecosystems functioning. • Often thought of in terms of human wellbeing. • Indirect-use value of biodiversity (these services are not factored into the marketplace).

34. Ecosystem Services—examples • Photosynthesis • Nutrient cycling • Decomposition

35. Tree of Life III: Eukaryotes (Fungi and Animals) ASAB - NUST Fall 2012

36. TOL III: Fungi and Animals • Fungi and animals probably share a common ancestor with choanoflagellates (collar-flagellates) based on genetic data • Cell wall components and other complex biosynthetic pathways are similar between fungi and animals

37. TOL III: Fungi and Animals fungi choanoflagellates animals single-celled protistan ancestor

38. TOL III: Fungi • Primarily terrestrial • No motile cells except in reproductive cells of chytrids • Chitin in cell walls • Unique features of chromosomes and nuclear division • Dominant part of life cycle has only one set of chromosomes per nucleus

39. TOL III: Fungi • Most are filamentous, multicellular; a few are unicellular (chytrids, yeasts) • Oldest fossils 450-500 million years ago • About 70,000 species described; estimated to be up to 1.5 million • 4 lineages: chytrids, zygomycetes, ascomycetes, basidiomycetes

40. TOL III: Fungi zygos ascos chytrids basidios

41. TOL III: Fungi • Consumers by absorption • In addition to natural sources of organic matter, can obtain nutrition from a wide variety of man-made substrates (cloth, paint, leather, waxes, jet fuel, photographic film, etc.) • Food-obtaining strategies: decomposers, parasitic, predaceous, symbiotic

42. TOL III: Fungi • Decomposers: use dead organic matter through excretion of digestive enzymes • Parasitic: obtain organic matter from living cells; many cause disease this way (pathogens) • Predaceous: trap and kill small organisms (nematodes, protozoans) • Symbiotic: form mutualistic relationships with other organisms (lichens, mycorrhizae)

43. TOL III: Fungi Structure, Growth and Reproduction -usually consist of hyphae (thread-like filaments) -mass of hyphae = mycelium -grow under a wide range of conditions -reproduction mostly sexual by spores; but asexual reproduction is common

44. TOL III: Fungi fungal mycelium on wood

45. TOL III: Fungal Diversity (chytrids) • Mostly aquatic • Reproductive cells with a characteristic flagellum • Unicellular or multicellular with a mycelium • About 750 species • One cause of frog die-offs

46. TOL III: Fungal Diversity (zygomycetes) • Mostly decomposers, a few parasitic • Multicellular, filamentous • About 600 species known • Best known as the bread molds • About 100 species form mycorrhizae with plant roots (now thought to include many more undescribed species)

47. TOL III: Fungal Diversity (ascomycetes) • Filamentous except for yeasts (unicellular) • Mostly decomposers or parasitic, some predaceous or symbiotic • Over 30,000 described • Includes most Fungi Imperfecti (e.g., penicillium) • Economic importance: yeasts (bread, beer, wine); Dutch elm disease, chestnut blight, ergots; edible fungi (truffles, morels); antibiotics

48. TOL III: Fungal Diversity scarlet cups ergot on rye Cordyceps ascomycetes

49. TOL III: Fungal diversity yeast (ascomycete) bread wine beer

50. TOL III: Fungal Diversity morels truffles edible ascomycetes