Module 3 Biodiversity PDF

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This material has been reproduced and communicated to you by or on behalf of University of the Philippines pursuant to PART IV: The Law on Copyright of Republic Act (RA) 8293 of the “Intellectual Property Code of the Philippines”. The University does not authorize you to reproduce or communicate this material. The Material may contain works that are subject to copyright protection under RA 8293. Any reproduction and/or communication of the material by you may be subject to copyright infringement and the copyright owners have the right to take legal action against such infringement. Do not remove this notice. © Institute of Environmental Science & Meteorology, College of Science, University of the Philippines Diliman 1 Module 3 Env Sci 1 (Environment & Society) Biological Diversity & Biodiversity Loss Image credit: MTManglicmot Batangas, May 2011 Learning Outcomes ! Discuss the relationship between the living organisms and their environment ! Discuss the importance of biodiversity to the ecosystem ! Explain how people affect biodiversity ! Identify the major environmental problems associated with biodiversity and their mitigation ! Describe the major changes of Philippine biodiversity through time ! Identify biodiversity hotspots in the Philippines 3 © C.L.Ringor Biological Diversity or biodiversity is the variety of the earth’s species, the genes they contain, the ecosystem in which they live, & the ecosystem processes such as energy flow & nutrient cycling that sustain all life. It is coined in 1985 by the biologist Edward O. Wilson. 4 © CLRingor, Tawi-tawi, Sep 2019 Major Components of the Earth’s Biodiversity Genetic diversity. Variety of genetic makeup among individuals Species diversity. Variety among species or distinct types of living within a species organisms found in different habitats of the planet Miller & Spoolman 2016 Ecological diversity. Variety of terrestrial & aquatic ecosystems Functional diversity. Biological or chemical processes or found in an area or on the Earth functions, e.g., energy flow & matter cycling, needed for the survival of the species & biological communities. Image credit: Miller & Spoolman, 2016 5 Species Diversity Species diversity has three qualities: (1) species richness — population. Merely counting the number of species is not total number of species; (2) species evenness — relative enough to describe biological diversity. Species diversity has abundance of species, & (3) species dominance — most to do with the relative chance of seeing species as much as abundant species. Consider the figure below showing two it has to do with the actual number present communities. At first, you might think that the two communities have the same species diversity because they have the same number of species. But if you look closely, The difference between species richness & species evenness. Communities A & the number of each species is different. In community A, B have the same number of species but different relative abundances. there are many elephants while the other species only have Community A depicts species richness, while community B illustrates species two each. In community B, there is even number of species; evenness. There is a dominant species in community A, which is the elephant; while in community B, there is none, 8. 2 allBiological species have equal abundance. Basics Image 147 which means each species has the same number of Diversity credit: Botkin & Keller, 2011. (a) A (b) B FIG URE 8. 4 Diagram illustrating the difference between species evenness, which is the relative 6 abundance of each species, and species richness, which is the total number of species. Figures (a) and (b) have the same number of species but different relative abundances. Lay a ruler across each diagram and count the number of species the edge crosses. Do this several times, and determine how many species are diagram (a) and diagram (b). See text for explanation of results.  How many species exist today? No one knows the exact number The Number of Species on Earth because new species are discovered all the time, especially in little- explored areas such as tropical savannas & rain forests & many more are still waiting to be discovered, especially in the ocean. It is estimated that there are 8.7 M (±1.3 M standard error) species globally, of which, 2.2 M (±0.18 M standard error) are marine (Mora et al., 2011). About 86% of the species are on land & 91% in the ocean still await description. Most of the species on Earth are insects (about 668,000 - 1 M+) & plants (480,000 - 530,000). There are also many species of arachnids (about 100,000). In contrast, mammals (our own kind), has only about 4,000 - 5,000 species, about half a percent of all animals. If the total number in a species were the only gauge of a species’ importance, we would not matter. Data from Mora et al., 2011 7 Why Value Biodiversity? Utilitarian. A species or group of species provides a product that is of direct value to people. Public service. Nature & its diversity provide some service, such as taking up carbon dioxide or pollinating flowers, that is essential or valuable to human life & would be expensive or impossible to do ourselves. Ecological. Species have roles in their ecosystems, & that some of these are necessary for the persistence of their ecosystems, perhaps even for the persistence of all life. Moral. Species have a right to exist, independent of their value to people. Theological. Some religions value nature & its diversity, & a person who subscribe to that religion supports this belief. 8 Image credit: Philippine Star https://www.philstar.com/nation/2018/07/30/1838003/pangolins-sea-turtles- seized-palawan  Why Value Biodiversity? Opinion Trends in Ecology and Evolution January 2012, Vol. 27, No. 1 Aesthetic. The beauty of nature, that including the variety biotic–abiotic of life largely occur at the level of interactions an ecosystem. However, sometimes what matters is not ecological processes, rather than in the delivery of ecosys- only the presence of a particular component or its amount tem services, the impacts of environmental change on but also the variety or diversity of types (i.e. the biodiver- Recreational. ecosystem services People mightenjoy getting often out be nonlinear, hard to pre- sity). These roles of biodiversity are closest to the ecosys- into nature, not just dict and/or irreversible because it is tems services approach outlined above but here the specific beautiful to look at but because it We propose that the confusion over the role that biodi- biodiversity–process interaction is recognised so that al- provides us with healthful activities that versity plays in ecosystem services can be resolved by though the functional diversity of soil organisms might be we enjoy recognising that different relations exist at the various important for ecosystem processes, bird species richness levels of the ecosystem service hierarchy numbered as may not be. shown in Figure 1. Biodiversity can be a regulator of funda- (ii) Biodiversity as a final ecosystem service: biological Spiritual. The way contact with nature & mental ecosystem processes, a final ecosystem service itself, diversity at the level of genes and species contributes its diversity often moves people, an or a good. These distinctions are set out below and in Table 1. directly to some goods and their values. For example, uplifting often perceived as a religious (i)experience Biodiversity as a regulator of ecosystem processes: the potential value of wild medicines and the potential biodiversity is a factor controlling the ecosystem processes benefits from bioprospecting increase directly with the that underpin ecosystem services. For example, the dy- number and evolutionary distinctiveness of species. Genet- namics of many Creative. soil nutrient Artists, writers, & cycles are determined by the musicians ic diversity of wild crop relatives is important for the find stimulation composition for theircommunities of biological creativity in in the soil [20,21], improvement of crop strains, and the same will be true nature & its diversity resilience to pests and environmental change is also in- for biofuel crops and livestock. Therefore, both genetic creased in more diverse biological communities and, in diversity (or surrogates, such as wild species richness or many contexts, higher biodiversity is associated with in- phylogenetic diversity) and wild species diversity (implic- creased ecosystem functions [23–27]. Therefore, the biolog- itly including genetic and phylogenetic diversity) are ical composition of ecosystems, measured as biodiversity, final ecosystem services directly contributing to goods has a key role in ecosystem service delivery. Ecosystem (Figure 1). In the case of these final ecosystem services, processes 9 generally depend on the right combinations of © CSPascua,ecosystems Ilocos Norte,could be specifically managed for the diversity Apr 2013 certain biotic and/or abiotic components being present in of the desired biodiversity components. Ecosystem Services of Biodiversity Table 1. A preliminary assessment of the nature, management priorities and implications of biodiversity playing its three different roles in ecosystem services Biodiversity acting as: A regulator of ecosystem processes A final ecosystem service A good What kind of organism? Microorganisms: decomposition and Wild crop and livestock relatives: ensuring Large vertebrates, especially birds, nutrient cycling genetic diversity to provide resilience of mammals and conspicuous flowering Primary producers (plants on land and in food production systems against future plants: recognised for their charisma and water): biomass production and carbon capture climate change/diseases and so on aesthetic appeal Organisms with secondary compounds: Flagship or umbrella species: providing Top predators, parasites: population regulation potential for commercial exploitation, for protection for wider communities and Pollinators: stability of nonagricultural ecosystems example novel pharmaceuticals habitats Pollinators: security of many food crops Phylogenetically distinct species: maintaining evolutionary diversity Endangered species: maintaining taxonomic diversity What kind of ecosystem management? Inputs need to be managed to achieve Management to maintain the necessary Directed and often very focused productivity and maintain nutrient cycles range of species groups and habitat or management for enhancing viability of and decomposition but with the risk of landscape types; has had, and will continue individual target species or species groups reducing the ability of the system to deliver to have, profound implications for other services management practices; often potential Importance of maintaining diversity for conflicts, especially if the maximising of one resilience, and resistance to predictable and service is a management goal unpredictable future environmental change How do humans benefit? Healthy fertile soils, clean air, clean water, Enhancing genetic variability for goods Cultural services, recreation, tourism, disease and pest regulation, climate such as novel pharmaceuticals, crop strains, aesthetic enjoyment, inspiration and regulation, and food and fibre production livestock breeds and pollinators. education How important is ‘diversity’ compared with biomass or composition? For some services and over the short term, Diversity within and among relevant groups Preserving species richness is primarily composition and biomass might be more of species is essential; might be possible to about diversity important attributes but little is known of the preserve some elements of this diversity in functional roles of most soil organisms and gene or seed banks but these are unlikely to there is no reason to assume a lesser role for conserve the full range of diversity biodiversity here than elsewhere Adapted from Mace et al., 2012 Biodiversity 10 provides resilience (an ‘insurance’ role)  Biological Evolution is a change in inherited characteristics of a population from generation to generation. It is a one-way process, i.e., irreversible. Once a species is extinct, it is gone forever; when a new species evolves, it cannot evolve backward into its parents. It is responsible for the development of the many species of life on Earth. Four processes lead to evolution: (1) mutation, (2) natural selection, (3) migration, & (4) genetic drift. Image credit: SogetiLabs https://labs.sogeti.com/natures-evolutionary-intelligence- genetic-algorithms-and-its-practical-applications/biological-evolution/ 11 Mutation is the random change in DNA molecules that make up genes. These changes are caused by various factors. Sometimes an external agent comes in contact with DNA & alters it. Radiation (e.g., X rays & gamma rays) can break the Migration & Geographic Isolation. When two populations of the same DNA apart or change its chemical structure. Certain chemicals & viruses can also species become geographically isolated from each other for a long time change DNA. In some cases, a cell or an offspring with a mutation cannot survive. In (geologic time scale), the two populations may change so much that they others, the mutation simply adds variability to the inherited characteristics. Still, in can no longer reproduce together even when they are brought back into other cases, individuals with mutations are so different from their parents that they contact. In this case, two new species have evolved from the original cannot reproduce with normal offspring of their species, so a new species has been species. Image credit: https://phys.org/news/2020-02-skulls-beaks-darwin- created. Image credit: http://www.ashg.org/education/everyone_1.shtml finches-diverse.html Genetic drift refers to changes in the frequency of a gene in a population due not to mutation, selection, or migration, but simply to chance. One Natural selection is the process of increasing the proportion of offspring. Key way this happens is through the founder effect. It occurs when a small factors that affect this process are inheritance of traits from one generation to the number of individuals are isolated from a larger population. They may next & some variation in these traits (genetic variability), environmental variability, have much less genetic variation than the original species & the differential reproduction (differences in numbers of offspring per individual), which characteristics will be affected by chance. These individuals may be more varies with environment, & influence of the environment on survival & reproduction. poorly or neutrally adapted. Image credit: http://evolution.berkeley.edu/ Image credit: https://www.nationalgeographic.com/news/2018/05/animals- evolibrary/article/evo_24 mothers-day-parents-babies/ 12  Biological Evolution Biological diversity is always changing; which species are present in any one location can change over time. Adaptation has no rigid rules; species can adapt in many ways in response to environmental conditions. Complexity is a part of nature; threats to one species are not necessarily threats to another Species are always evolving & adapting to environmental change. When they cannot evolve fast enough to keep up with the changing environment, they become endangered. Image credit: ScienceSourceimages 13 Species Interaction In general, species interact in three ways: (1) competition, (2) mutualism, & (3) predation– parasitism. These interactions affect evolution, the persistence of species, & the overall diversity of life. Throughout the Earth’s history, organisms have evolved together, so predator, parasite, prey, competitor, & symbiont have adjusted to one another. However, human interventions frequently upset these adjustments. 14 © CLRingor, UP Diliman, Dec 2019  (42.8°–62.6°F) (Figure 8.12a). Where species B occurs principle and the ecolog alone, it is found from 6° to 23°C (42.8°–73.4°F) (Figure important about the con 8.12b). When they occur in the same stream, their tem- to conserve a species in i perature ranges are much narrower. Species A lives in the sure that all the require upstream sections, where the temperature ranges from 6° Conservation of endange to 14°C (42.8°–57.2°F), and species B lives in the warmer ter of putting many ind downstream areas, where temperatures range from 14° to area. All the life requirem 23°C (57.2°–73.4°F) (Figure 8.12c). be present—we have to Competition & Ecological The temperature range in which species A occurs but also its habitat and it when it has no competition from B is called its funda- Niches mental temperature niche. The set of conditions under which it persists in the presence of B is called its realized temperature niche. The flatworms show that species divide 8.5 Symbios up their habitat so that they use resources from differ- Competitive Exclusion Principle ent parts of it. Of course, temperature is only one aspect Our discussion up to thi sion that species interact states that two species that have of the environment. Flatworms also have requirements by interfering with one an exactly the same requirements cannot relating to the acidity of the water and other factors. We portant. This term is deri could create graphs for each of these factors, showing the “living together.” In ecol co-exist in exactly the same habitat; range within which A and B occurred. The collection of tionship between two org one must win. This principle suggests all those graphs would constitute the complete Hutchin- and enhances each organ sonian description of the niche of a species. that there should be very few species. partner in symbiosis is ca Symbiosis is widesp But it is not the case. How did so mals and plants have sym many different species survive, & how competitors—to coexist because they Planaria A alone species. We, too, have s avoid competing. For example, Presence us that about 10% of o do so many co-exist? Part of the weight of symbiotic mi answer lies with the concept of hawks & owls feed on similar prey but A intestines. They help ou ecological niche. hawks hunt during the day & owls at habitat that supplies all benefit. We become awa night. (a) 5 10 15 20 when it changes—for exa Ecological niche is a species’ way Planaria B alone that kill some of these org Competition occurs between that community, or when Presence of life in a community & includes all of B and ingest new strains of physical, chemical, & biological members of the same species known traveler’s malady, conditions that a species need in (intraspecific) & between members of Another important k curs between certain ma order to live & reproduce in an different species (interspecific). When (b) 5 10 15 20 on the northern tundra m ecosystem. It is a specific role that a species compete, they either migrate Planaria A & B together ries with it many compa reindeer is a ruminant, w to another area (if possible), or shift Presence species play in its ecosystem & (Figure 8.13) teeming wi should not be confused with its their feeding habits or behavior A B centimeter). In this par habitat. through natural selection & evolution, respiration of microorga gested by the reindeer w or suffer a sharp population decline, 5 10 15 20 isms digest cellulose, tak Species that require the same or become extinct in that area. As (c) Temperature, °C stomach, and make prot digest the parts of the ve resources can coexist by using those mentioned, most species do not die This figureFshows I G U R E 8two. 1 2 flatworm Fundamental species that live and realized on The niches: streams. occur- Each not digest itself (in parti species liverence of freshwater flatworms in cold mountain streams in within a specific range of temperatures. When they live resources under different out of competition either because Great Britain. (a) The presence of species A in relation to temperature of cell walls in woody tis in the same stream,where in streams theirit occurs temperature alone. (b) ranges became The presence narrow. of species B in Thement: They can survive o environmental conditions. It is habitat they have avoided the competition or flatworms relation show to thattemperature speciesindivide streamsupwhere it occurs their habitat so(c) alone. Thethey use that oxygen. One of the few temperature range of both species in streams where they occur complexity that allows complete developed traits that allow them to resources together. from different Inspect the parts threeof it. The graphs: Whattemperature range in which is the effect of each such an environment exi 20 share the wealth or developed a species A species live alone on the called fundamental temperature niche; stomach. The bacteria is other? competitors—& not-so-complete when it live together with species B, it is called realized particular niche. temperature niche. 15 Mutualism In this interaction, two species interact in ways that benefit both by exploiting the other. Examples are having pollen & seeds dispersed for reproduction, being supplied with food, & receiving protection. Mutualism is widespread & common. In humans, about 10% of our body weight is actually the weight of symbiotic microorganisms that live in our intestines. They help our digestion, & we provide a habitat that supplies all their needs. We become aware of this intestinal community when it changes—for example, when we take antibiotics that kill some of these organisms, changing the balance of that community, or when we travel to a foreign country & ingest In the ocean, the clown fish are protected from predator fish by the stinging tentacles of the anemone. The anemone receives protection from polyp-eating fish, like Butterfly Fish, which the clown fish chases away. The new strains of bacteria & upset our anemone also gets fertilizer from the feces of the clown fish. stomach. Another example is crop plants. Mutualism promotes biological single species almost invariably leads Plants depend on animals to spread diversity. If we want to save a species us to conserve a group of species, their seeds & have evolved symbiotic from extinction, we must save not not just a single species or a particular relationships with them. That’s why only its habitat & niche but also other physical habitat. fruits are so eatable; it’s a way for species that it mutually interacts. This plants to get their seeds spread. suggests that an attempt to save a 16  How do prey defend themselves against or avoid predators? Some of the ways prey defend themselves from predators include running (cheetah), swimming, or flying fast; developing a high sense of sight or smell that alerts them to the presence of predators; & having protective shells (e.g. armadillos & turtles), thick bark (e.g. giant sequoia trees), or spines (e.g. sea urchin) or thorns (cacti & roses). © Ken Geiger. https://www.nationalgeographic.com/news/ 2016/01/160122-cheetahs-animals-science-fastest- https://www.fodors.com/world/north-america/usa/arizona/tucson/ cincinnati-zoo/ https://www.projectnoah.org/spottings/238966008 experiences/news/10-of-the-meanest-ugliest-cacti-on-earth 1 2 https://www.worldwildlife.org/species/sea-turtle 3 4 © Michael Nichols. https:// www.nationalgeographic.com/news/ 17 2012/12/121205-sequoia-redwoods-trees-old- national-park-science-environment/ Other species use the camouflage of certain shapes & colors. Some lizard species look like bark of trees. A leaf insect can be almost invisible against its background. Other organisms that blend with their surroundings are African stone plants, stone fish, toads & frogs, & brown hare. 18  Stinkbugs Oleander Stinging nettles © Associated Press. https://www.peninsuladailynews.com/ © nada54/shutterstock.com news/state-commission-restricts-octopus-hunting/ Chemical warfare is another common strategy for prey species. Some discourage predators by containing or emitting chemicals that are poisonous (oleander plants), irritating (stinging nettles & bombardier beetles), foul smelling (skunks & stinkbugs), or bad tasting (buttercups & monarch butterflies). When attacked, some species of squid & octopus emit clouds of black ink, allowing them to escape. 19 Many bad-tasting, bad-smelling, toxic, or stinging prey species have evolved warning coloration, brightly colored advertising that helps experienced predators to recognize & avoid them. Examples are the brilliantly colored, foul-tasting monarch butterflies, colorful grasshoppers, & poisonous frogs. 20  Monarch Wasp Coral Snake Viceroy https://journeynorth.org/tm/monarch/Viceroy1.html Hover fly Milk Snake Some butterfly species gain protection by looking & acting like other, more dangerous species, a protective device known as mimicry. For example, the nonpoisonous viceroy butterfly mimics the monarch butterfly, the harmless hover flies mimic the wasp, & the nonvenomous milk snake mimics the venomous coral snake. Other prey species use behavioral strategies to avoid predation. Some attempt to scare off predators by puffing up (blowfish), spreading their wings (peacocks), or mimicking a predator. Some moths have wings that look like the eyes of much larger animals, moth that looks like a spider, & a caterpillar whose tail looks like a snake. Other prey species gain some protection by living in large groups such as schools of fish & herds of antelope. 21 22  © Nikolay Denisov, Alamy. https://www.nationalgeographic.com/animals/ 2018/08/saiga-antelope-poaching-disease/ © Frans Lanting, Mint Images, Corbis https:// 23 www.nationalgeographic.com/news/2014/5/140527-migration-zebra- mammal-africa-namibia-botswana-environment-conservation/ Biomes area of the planet that can be classified according to the plants & animals that live in it. A biome is different from an ecosystem. It is a specific geographic area notable for the species living there. A biome can be made up of many ecosystems. 24 © CLRingor, Ifugao, Dec 2009  Differences in long-term average World’s Major annual precipitation & temperature Terrestrial Ecosystems lead to the formation of different terrestrial biomes & largely determine their location Image credit: Miller, 2003 25 Biome: Tropical Rainforest Tropical rainforests are found near the equator, where hot, moisture-laden air rises & dumps its moisture. These lush forests have year-round, uniformly warm temperatures, high humidity, & almost daily heavy rainfall. This fairly constant warm, wet climate is ideal for a wide variety of plants & animals. Tropical rain forests have a very high net primary productivity. They are teeming with life & possess incredible biological diversity. Although tropical rain forests cover only about 2% of the earth’s land surface, ecologists estimate that they contain at least 50% of the known terrestrial plant & animal species. Of these are the Philippine Tarsiers (Tarsius syrichta), which are nocturnal insectivorous primates. The main predators are humans feral cats, civets, raptors, snakes or monitor lizards. They live in primary & secondary forest, mangroves; dense vegetation & trees that offer protection (e.g., tall grasses, bushes, bamboo shoots). They are found in Samar, Leyte, Bohol, Dinagat, Siargao, & Basilan. http://www.tarsiusproject.org/philippine-tarsiers/ 26 © CLRingor, Bohol, May 2010 World’s Major Marine Aquatic Systems The key factors that High tide determine the types & Low tide Coastal Zone Open Sea Depth in numbers of aquatic meters Sea level organisms are 0 temperature, dissolved Photosynthesis oxygen, food, light, & 50 nutrients Estuarine Euphotic Zone Zone 100 Continental shelf 200 Bathyal Zone 500 Twilight 1,000 1,500 Water temperature drops rapidly between the 2,000 euphotic zone and the Abyssal abyssal zone in an area Zone called the thermocline. 3,000 Darkness 4,000 5,000 © Cengage Learning 10,000 Image credit: Miller & Spoolman, 2016 0 5 10 15 20 25 30 Water temperature (°C) 27 Biome: Coastal Zone Coastal zones are warm, nutrient-rich, shallow water that extends from the high-tide mark on land to the gently sloping, shallow edge of the continental shelf (the submerged part of the continents). It makes up less than 10% of the world’s ocean area, but it contains 90% of all marine species & is the site of most large commercial marine fisheries. This zone’s aquatic systems include estuaries, coastal marshes, mangrove forests, & coral reefs. 28 © CLRingor Tawi Tawi, September 2019  Loss of Biodiversity & Extinction Extinction is the rule of nature. Local extinction means that a species disappears from a part of its range but persists elsewhere. Global extinction means a species can no longer be found anywhere. Although extinction is the ultimate fate of all species, the rate of extinctions has varied greatly over geologic time & has accelerated since the Industrial Revolution. Recent estimates reveal two mammal extinctions per 10,000 species per 100 years. But the number of © Ant Photo Library/Science Source vertebrates & mammal species that have gone extinct in the last 100 years would have taken 800 - 10,000 yrs to disappear (Ceballos et al., 2015). These estimates reveal an exceptionally rapid loss of biodiversity over the last few centuries, indicating that a sixth mass extinction is already under way (Ceballos et al., 2015). Above left: A tiny froglet can be seen in the mouth of its mother, a gastric- brooding frog. In this novel form of parental care, the female swallowed her fertilized eggs. Her stomach then stopped producing acid, becoming a makeshift womb. Later, she regurgitated fully formed froglets. Two species of gastric-brooding frogs made their homes in creeks in a relatively small area of tropical forest in Queensland, Australia, the southern (Rheobatrachus silus) & the northern gastric-brooding frog (Rheobatrachus vitellinus). The species were discovered in 1973 & 1984, respectively, but by the mid-1980s they had both disappeared. Left: The Pyrenean ibex (Capra pyrenaica) was a wild goat native to the Iberian Peninsula. It went extinct in 2000 due to hunting & competition from domestic animals. https://www.nationalgeographic.com/news/2013/3/130305-bring-back- extinct-species/ 29 © Simon Littlejohn, Foto Natura/Corbis The Five Mass Extinctions (Big Five) Mass extinctions are characterized by elevated extinction rates relative to background & long-lasting ecosystem change (Hull, 2015). The extinction in shelly marine invertebrates have generally declined (grey bars), with the Big Five mass extinctions (red bars) standing out as relative lows in standing diversity (black line). The leading hypothesized trigger are glaciation, volcanism, & impact. The Big Five are thought to have killed more than 75% of species alive at the time. Image credit: Hull, 2015. 444 375 251 200 66 MYA Glaciation (Ice Age) Volcanism Impact 30 The 6th Mass Extinction? The modern extinction rates are exceptionally high, that they are unprecedented & increasing, & that they suggest a mass extinction under way— the sixth of its kind in Earth’s 4.5 billion years of history (Ceballos et al. 2015). If the currently elevated extinction pace is allowed to continue, humans will soon (in as little as three human lifetimes) be deprived of many biodiversity benefits. On human time scales, this loss would be effectively permanent because in the aftermath of past mass extinctions, the living world took hundreds of thousands to millions of years to rediversify (Ceballos et al. 2015). This is truly an urgent call to action—to conserve already threatened species & to alleviate Roughly a third (8 pressures on their populations—notably habitat examined are experien loss, overexploitation for economic gain, & climate change. All of these are related to human a considerable magn population size & growth, which increases creasing species varie consumption, & economic inequity. 30% or more in the c in the case of amphibi many are now consi roughly 30% of all dec Fig. 4. The percentage of decreasing species classified that they by IUCN as “endan are consider (including “critically endangered,” “endangered,” “vulnerable,” and “endangered.” That s threatened”) or “low concern” Image credit: Ceballos (including et al., 2015 and “data-def “low concern” 31 in terrestrial vertebrates. This figure emphasizes that even species that h strong sign of the se yet been classified as endangered (roughly 30% ologicalin the extinction ep case of all verte 2 are declining. This situation is exacerbated in theIncase our 10,000-km of birds, for whic to 55% of the decreasing species are still classified species ranges as “low from le concern.” Loss of Biodiversity geographic distributio (i.e., percentage) of & Extinction gibbon (Nomascus hainanus), to many millions tropical of individu regions have decreasing common species such as expected, the barn swallow given their (H 2 Biodiversity loss reduces the availability of rustica). Similarly, the smallest rangesproportions (i.e.,