BVB225 Ecosystems & Biodiversity Revision Slides PDF

25/10/2023 BVB225: Ecosystems & Biodiversity Revision sildes for the biodiversity section Dr. Matt Phillips School of Earth, Environmental and Biological Sciences R block Room 117 (ph. 31384805) [email protected] 1 Conditions on the ear...

25/10/2023 BVB225: Ecosystems & Biodiversity Revision sildes for the biodiversity section Dr. Matt Phillips School of Earth, Environmental and Biological Sciences R block Room 117 (ph. 31384805) [email protected] 1 Conditions on the early Earth, 4 BYA Ocean near present volume Ocean anoxic and was reducing (as opposed to oxidizing) 100 present concentration of CO2 ; also N2, H2S,NH3, H20, CH4 No ozone layer, so high UV Sun dimmer by 30% Mass volcanism, regular bolide (asteroid/comet) bombardment Mid-ocean ridges abundant Torrential rains carried sediments to the oceans Hundreds of small crustal plates forming 2 1  25/10/2023 Miller-Urey experiment Stanley Miller Amino acids (basis of proteins) H2O, NH3, CH4,CO2, e- → sugars purines } (basis of nucleic acids) 3 Simple molecules, lightning, Organic compounds water/atmosphere mixing Concentrated Organic Evaporation compounds Eigen Hypercycles: last catalyzes the first A →B B →C C →A Beginnings of replication/heredity = a platform for evolution and escaping entropy (i.e. life) 4 2  25/10/2023 Iron-sulfur world Volcanic hydrothermal vents: high pressure and high temperature (>100C) Gunter Wächtershäuser Passing dissolved volcanic CO, NH3, H2S over catalytic transition metals FeS, NiS → catalytic metalopeptides →Numerous amino acids and pyruvate produced (overcoming free energy constraints) A number of reactions among the Citric acid cycle have been shown experimentally 5 Prebiotic soup does not explain the origins of metabolism well - insufficient temp/pressure without established enzymes Iron-sulfur world does not explain origins of information systems (e.g. RNA) well - too unstable? In combination, these models show that the evolution of life from non-life in the conditions of the early earth are very plausible We just don’t know the details well, and perhaps too much has been erased over time for us to know 6 3  25/10/2023 Moggill Field Trip computer lab 7 Biodiversity indices – Revision from BVB102 Species richness = the number of species 4 species: comprising 6, 4, 2, 3 Diversity indices provide more individuals in a community information about community composition than simply species richness; they also consider evenness D = 1- Σ i i n (n -1) - the relative abundances of different N (N-1) species 30+12+2+6 D = 1- 15 (14) Variables D = 1 – 50/210 = 1-0.238 = 0.762 D = Simpson’s diversity ni = individuals of each species N = individuals across all species 8 4  25/10/2023 Drivers of diversity Energy, for trophic levels and population maintenance / size Plentiful water and nutrients Microniche differentiation Geographic isolation Time since disturbance 9 Drivers of diversity Diversity begets diversity Grime’s (1973)* Intermediate disturbance hypothesis? *Or Horn (1975) or Connell (1978), depending on how much of the hypothesis is considered 10 5  25/10/2023 Drivers of diversity Rainforest trees: negative density dependence? Abundant species are more susceptible to pathogens (e.g. fungi) and herbivores (inc. insects) in high productivity/hot/wet ecosystems. (Bagchi et al., Nature, 2014) So, selection for lower abundance of individual species could promote high species richness and diversity in closed canopy ecosystems 11 Drivers of diversity Topography and other spatial diversity You saw these last week (2 typical forest types around Brisbane). List five abiotic differences between these sites on your worksheet A. B. 12 6  25/10/2023 Phylogenetic Diversity (PD) – sum of phylogenetic branch lengths – an alternative measure of biodiversity for prioritising conservation management Which is more diverse: Hypsiprymnodon or Osphranter Consider species richness and PD Celik et al. (2019) 13 Phylogenetic Diversity (PD) – sum of phylogenetic branch lengths Phylogenetic Endemism Sum of endemic branch lengths e.g. those endemic to Queensland (How much PD would be lost if all Qld was concreted) 14 7  25/10/2023 Hypothetical example: bird species richness and diversity Comparing: easy to see birds in King George Square – versus Hard to find birds in a tree in New Guinea’s Torricelli Mountains Rock pigeons (Columba liva) and bin chickens Blue bird of paradise (Threskornis molucca) (Paradisornis rudolphi) Abundance, Richness, Simpson’s diversity index, rarefaction, phylogenetic diversity 15 After looking for 5 minutes King George Square Torricelli Mountains Sp 1 27 Sp 1 4 Sp 2 9 Sp 2 2 Sp 3 8 Sp 3 1 Sp 4 7 Sp 4 1 Sp 5 4 Sp 5 1 Sp 6 1 Abundance: 56 to 9, but what’s the ascertainment bias? Species richness: 6 to 5, ascertainment bias again? Simpson’s diversity index: 0.72 to 0.81, is this meaningful on a small sample? Phylogenetic diversity: 235 Ma to 137 Ma Phylogenetic endemism (Oz/NG): 31 Ma to 137 Ma 16 8  25/10/2023 King George Square Torricelli Mountains Sp 1 27 Sp 1 4 Sp 2 9 Sp 2 2 Sp 3 8 Sp 3 1 Sp 4 7 Sp 4 1 Sp 5 4 Sp 5 1 Sp 6 1 After looking for 5 minutes, but So, trying to account for Rarefaction analysis: how sampling effort gives an much more might we find if indication of how much we we kept on looking? didn’t see 17 Why are flowers more stable over evolutionary time than leaves or bark? Consider relative environmental selection pressures, interaction constraints of sex, including animal intermediaries ©T.Scharaschkin 2007 ©T.Scharaschkin 2007 Accacia baileyana Acacia falcata 18 9  25/10/2023 Rainforest Open forests Rainforest Severe Some initial spread aridification forest opening Counter to the global climate change political narrative NG rain shadow 19 Among all the inhabited continents, Australia (on average) Is the flattest, less erosion (also little & glaciation) Has the most nutrient poor soils Has the least and least predictable rainfall (El Nino/La Nina) Is the most fire prone As a result Open sclerophyllous/xeromorphic vegetation Massive reptile diversity Many ant/termite dominated ecosystems Many plant symbiotic relationships Diversification of open woodland & grassland animals 20 10  25/10/2023 Xeromorphic Scleromorphic leaves (blue gum) leaves Deciduous leaves (white ash) 21 Plate tectonics – heading north and bumping into Asia (biotic interchange) 22 11  25/10/2023 Fire dependence encourages open communities serotiny epicormic growth Nutrient release 23 ‘Megalania’ and Implications for animals Genyornis resource deficits amplify up the food chain → reptile dominance? Lower energy/nutrient/water needs Thorny Thylacoleo & Wonambi devil Meiolania Mekosuchine crocodiles Death adder 24 12  25/10/2023 Implications for animals Echidna Tough leaves, chemical defences, El Nino/La Nina drought cycles → Mammals in the slow lane: lower metabolism / reproduction Koala Bandicoots the partial exception Hopping mouse 25 Implications for animals And hoppers Miocene forest opening: energy saving → gliders Northern bettong Feathertail glider Kultar (only hopping carnivore) Sugar glider Giant short- faced kangaroo 26 13  25/10/2023 Implications for animals Many termite and ant dominated ecosystems Large elaiosomes are costly with nutrient deficient soils, so ants attracted to seeds with small elaiosomes and burry Termites can survive long them – protecting them from droughts on dead grass wildfires 27 Polysaccharide of glucose units 28 14  25/10/2023 Charophyta Middle lamella Plasmodesmata, for transport through cell walls of food/hormones 29 Alternation of Generation- pollen Sporophyte (2n) Embryo (2n) Microsporangia Megasporangia (2n) (2n) Zygote(2n) microsporocytes (2n) megasporocytes (2n) FERTILISATION Heterosporous MEIOSIS Egg (n) Sperm (n) gametes (n) Pollen? microspores (n) megaspores (n) Ovule/Seed? Archegonia (n) Antheridia (n) Gametangia (n) Microgametophyte (n) Megagametophyte (n) 30 15  25/10/2023 Advantages of elaboration of zygote into a sporophyte 1. Higher production of spores 2. Prevents expression of recessive, deleterious alleles 3. Generates variability in the sporophyte generation 31 Problems with the land for aquatic organisms 1. Gas exchange 2. Lack of buoyancy 3. Locomotion 4. Food doesn’t come to you 5. Desiccation (adult and embryo) 6. Specific heat and thermal conductivity What have land plants come up with? 32 16  25/10/2023 Plant phylogeny and transitional fossils 33 Evasion tactics to minimize exposure to heat and drought 1. Dormancy for substantial part of life-cycle: e.g. ephemeral plants, some reptiles, mammals hibernate, most insects persist through extended droughts as seeds, eggs, or larvae (only the reproductive forms remain). 2. Nocturnal or crepuscular foraging (days in burrows or shade). (or photosynthetic dark reactions – CAM) 34 17  25/10/2023 Reducing Fennec fox heat load Low surface-area/volume ratio Reflective bark/leaves Sometimes Vertical shoot- body architecture joshua tree (Yucca brevifolia) Not so common in Oz, but e.g. in the Mojave desert Boabab (Adansonia gregorii) 35 Leaf size & angle of orientation help reduce heat loading Plants cool by evapotranspiration when water is available Smaller leaves cool faster than large leaves (thinner boundary layers) Vertical leaves have highest irradiation in early morning and evening, when water loss is less Brigalow: vertical, reflective leaves 36 18  25/10/2023 Minimize water loss Transpiration reduced in desert plants by microphylly, deciduousness, sunken stomata, waxy or pubescent leaves (reflects, also >boundary layer for slowing gas exchange). Thick waxy cuticle & sunken stomata 37 Controlling heat loss with reduced blood flow to surface WARM COLD heat flow SKIN Capillary bed Capillary bed arterial-venal arterial-venal anastomosis (shunt) anastomosis (shunt) CLOSED OPEN Vasodilatation Vasoconstriction 38 19  25/10/2023 From Watcher Nature Blog: C3 Carbon fixation: RuBisCO facilitates a reaction between a 5- carbon molecule called Ribulose-1,5-biphosphate, one H2O molecule and one CO2 molecule. This produces 2 molecules of glycerate 3-phosphate or 3PGA, which is that 3 carbon, “1st-step” product for which C3 is named. 39 RuBisCO is good at binding with carbon when there’s little free oxygen. But O2 competes with CO2 for binding sites. Then instead of making 2×3PGA molecules, RuBisCO catalyses a reaction that produces 1×3PGA and 1 “problem molecule” (Phosphoglycolate), and requires additional resources and energy to retrieve the carbon. This photorespiration (O2 added to RuBP) is exacerbated by heat, which enhances O2 competiting for RuBisCo binding sites. 40 20  25/10/2023 C4 Carbon fixation for hot, somewhat dry environments C4 works like this: CO2 is taken in through stomates during the day, but the carbon is initially fixed not by RuBisCO, but by another enzyme, PEP carboxylase, producing 4-carbon malic acid or oxaloacetic acid. The C4 acid is then transported from the leaf-surface mesophyll cells to bundle-sheath cells around vascular bundles. Hatch-Slack pathway, after the Australian scientists who discovered the pathway in 1966. PEP carboxylase has higher affinity for CO2 (or dissolved as HCO3-) & lower affinity for O2 than RuBisCO 41 Standard C3 leaf (left) and C4 leaf with Krans anatomy (below) - notice the bundle sheath cells with chloroplasts Spatial separation of initial carbon fixation (mesophyll cells) and the Calvin cycle (bundle sheath cells) 42 21  25/10/2023 C4 photosynthesis can be more water efficient. Light response curves of (A) an idealized C4 plant and (B) a C3 plant. For C4 plants, (1) the light saturation point is higher and (2) the light compensation point is lower than for C3 plants. Both relate to C4 plants increasing CO2 available to the Calvin-Benson cycle. 43 But: C4 has higher energetic demand. Fixing carbon twice requires 30 ATP per glucose, compared with 18 ATP for C3 And the carbon efficiency benefit of C4 decreases with lower temperatures (with less photorespiration). So, C4 has advantages, but also disadvantages. C3 still dominates globally. C4 is 5% of dicots, 40% of monocots 44 22  25/10/2023 Spatial separation Temporal separation of of carbon fixation carbon fixation Many desert plants Semi-arid & hot/humid Many desert plants but few desert plants 45 Physiognomic Classification Nutrients & water ©T.Scharaschkin 2007 46 23  25/10/2023 Many Australian rainforest mammals (inc. all southern) are either generalists also inhabiting wet sclerophyll or recent arrivals (past 1 Ma) from New Guinea Northern exceptions Why? 47 Australian rainforests: classification Webb (1959) Average size of canopy leaves Tree layers and canopy closure Species dominance (simple or complex in upper layers) Emergent trees Evergreen or deciduous Special growth forms (e.g., lianas, palms, tree ferns, araucarians (e.g. hoop pine), leaf physiognomy) 48 24  25/10/2023 Influence of local conditions on rainforest distribution Soil: rich or poor in nutrients Aspect: north and south facing slopes – large impact on soil moisture (Altitude & latitude) 49 Subtropical Rainforest ©T.Scharaschkin2006 Argyodendron (Booyong) Figure: courtesy of Dr. Mike Pole, Univ. of Queensland, St. Lucia 50 25  25/10/2023 Warm Temperate Rainforest Example tree: Ceratopetalum; typically dominated by one species of tree; at Lamington restricted to areas of poor soils Coachwood, NSW Christmas bush Figure: courtesy of Dr. Mike Pole, Univ. of Queensland, St. Lucia 51 Cool Temperate Rainforest Example trees: Nothofagus (‘Beech’), Phyllocladus (celery pine); e.g. Binna Burra, Tas SW, NZ Figure: courtesy of Dr. Mike Pole, Univ. of Queensland, St. Lucia 52 26  25/10/2023 Example trees: Araucaria, Dry Rainforest Dendrocnide (stinging tree) 53 Wet tropical/sub-tropical rainforest. Mix of old endemic and Asian migrants. Uneven multi-storey, wet all year 54 27  25/10/2023 Boundaries in Space As available moisture decreases, the boundaries between sclerophyll and ‘non-sclerophyll’ vegetation sometimes remain, depending on soil, fire history and other factors Figure: courtesy of Dr. Mike Pole, Univ. of Queensland, St. Lucia 55 Boundaries in Time Wet and dry sclerophyll ‘time capsules’ at Border Ranges NP & Moggill Regional Park. Euc can’t regenerate in low light, RF can’t tolerate fire. Infer when the last major fire occurred? ©T.Scharaschkin2008 56 28  25/10/2023 High nutrient soil: RF can grow in lower rainfall, e.g. Parts of Brisbane Underlying rock Basalt Scoria Rainforest Alluvium Sclerophyll Granite Acid volcanics 0 1000 2000 3000 Mean annual rainfall (mm) Low nutrient soil: RF can only grow with high rainfall, e.g. Fraser Is. 57 High light plant: Light green line Shade plant: Dark gree line 58 29  25/10/2023 Leaf Physiognomy & Climate The other driver: competition for light 59 Typical rainforest leaves Elliptical, with smooth margins As Mean Annual Temperature increases the proportion of species with entire (smooth) margins increases The proportion of species with non-entire (toothed) margins decreases WHY? 1. Toothed margins slow airflow for better gas exchange (which is lower at low temperature) 2. Toothed margins may be a way of increasing surface area slightly when having to freeze-proof by selecting for small size leaves 60 30  25/10/2023 Leaf Size Large leaves can be more efficient for creating a canopy for capturing light However, large leaves are more at risk of overheating, especially when low water availability for evaporative cooling Large leaves also under more threat from freezing/frost damage 61 Leaf Length & Mean Annual Temp. Leaf litter in Australian rainforests 62 31  25/10/2023 Drip Tips & Climate Syzygium luehmannii Ellenberg, H. 1985. Site conditions under which leaves develop “Drip Tips” Flora 176, 169-188 63 When science crosses into the public domain we need to consider prejudices 64 32  25/10/2023 Conservation prioritisation Formula/model Phylogenetic diversity contribution Threatened status e.g. https://www.edgeofexistence.org/ Current conservation attention Highest Australian mammal priority: Mountain pygmy possum (Burramys parvus) Public agreement? 65 Conservation prioritisation Formula/model Phylogenetic diversity contribution Threatened status e.g. https://www.edgeofexistence.org/ Current conservation attention Highest NZ plant priority: Fish guts plant (Chenopodium detestans) Public outrage about funding Formulae miss the nuances of decision making 66 33