Lecture Notes on Biodiversity PDF

1 UNIVERSITY OF TECHNOLOGY FACULTY OF SCIENCE AND SPORT Module: Environmental Studies Lecture #4 BIODIVERSITY Biodiversity is the variety of living organisms and the ecosystems and ecologi...

1 UNIVERSITY OF TECHNOLOGY FACULTY OF SCIENCE AND SPORT Module: Environmental Studies Lecture #4 BIODIVERSITY Biodiversity is the variety of living organisms and the ecosystems and ecological processes of which they are a part. Biodiversity can be divided into three categories. Genetic Diversity: refers to the variety of genes within a species Species Diversity: refers to the variety of living organisms within a region Ecosystem Diversity: refers to the variety of habitats, biotic communities and ecological processes in the biosphere. According to the Millennium Ecosystem Assessment, it is estimated that there are between five (5) million and thirty (30) million species. Only 1.7 - 2 million species have been formally identified. The greatest species diversity is exhibited by microbes, insects and small sea organisms. The areas richest in biodiversity are the tropical moist forests of Southeast Asia, Central Africa and West Central Africa and Tropical Latin America. IMPORTANCE OF BIODIVERSITY Agricultural Importance Human beings and other animals depend on plants to provide them with food. However, the number of different kinds of food we eat is limited when compared with the total number of edible species. More than fifty thousand (50,000) are thought to be edible, but but 90% of our needs are provided through 15 crops, with two-thirds of our calorie intake provided by three crops: rice, maize and wheat (Gruber, 2017). Forests are estimated to provide food for an estimated 1.6 billion people worldwide, who live within 5 kilometres of those forests (Ickowitz et al. 2022). The dominant livestock types are poultry, cattle (including cows and buffalo), pigs, sheep and goats. Other dominant meat types may vary based on country and can also include wild game, horse and duck (Ritchie et al., 2019). It is also important to maintain a broad genetic base for organisms, which are economically important. Plant scientists have developed genetically uniform, high yielding varieties of important food crops such as wheat. However, genetic uniformity resulted in increased susceptibility to pests and diseases. By crossing these “super strains” with genetically more diverse relatives, disease and pest resistance can be reintroduced into such plants. Wild plants therefore represent important sources of genes that can confer useful properties to conventional crops. For example, Wild tomato species in the Galapagos Islands have been found to be resistant to insects,  2 and can grow in salty soils (Gruber, 2017).. Industrial Importance Modern industrial technology depends on a broad range of genetic material from organisms, particularly plants that are used in many products. Plants supply oils, lubricants, perfumes and fragrances, dyes, paper, lumber, waxes, rubber, resins, poisons, corks and fibres while animals provide wool, silk, fur, leather, lubricants, waxes and transportation. The neem tree has been found to repel insects, has anti-inflammatory and anti-microbial properties and is an anti-oxidant. It has also been used in hair and skin products (Galan, 2019). The painted daisy (Chrysanthemum cinerariifolium) produces six toxins that are used to create pyrethrin, an insecticide (Brillon, 2022). Medicinal Importance The genetic resources of organisms are vitally important to the pharmaceutical industry, which incorporates hundreds of chemicals derived from organisms into its medicines. Approximately 50% of the approved drugs in the last 30 years are either produced directly or indirectly from natural products (Veeresham, 2012). Examples of these products include morphine, codeine, quinine, atropine and digitalis. Jamaica contains approximately 52% of the established medicinal plants that exist on earth and plants play an important role in traditional medicine here (Lowe et al., 2021). Plants used for medicinal purposes in Jamaica include cerasee, aloe vera, noni and guinea hen weed (Lowe et al., 2021). Animals too continue to be sources of drugs and are important in medical research. Ecosystem Stability Plants, animals, fungi and other microorganisms are instrumental in many environmental processes without which humans could not exist. Forests provide watersheds, from which we obtain water, and reduce the severity and number of local floods. Many species of flowering plants depend on insects to transfer pollen for reproduction. Soil dwellers from earthworms to bacteria develop and maintain soil fertility for plants. Bacteria and fungi decompose organic material, which allows nutrients to recycle in the ecosystem. Scientific Importance The study of organisms may lead to breakthroughs in several different fields including medicine, industry, genetic engineering and agriculture. Scientific research is therefore an important subset of all of these areas. Genetic Engineering This is the incorporation of genes from one organism into an entirely different species, making it possible to use the genetic resources of organisms on a much wider scale. The gene for human insulin has been engineered into a bacterium which subsequently become tiny chemical factories manufacturing, at a relatively low cost, the insulin required in large amounts by diabetics (Brinson Brothers, 2020). Genetic engineering has provided us with new vaccines, more productive farm animals, agricultural products with longer shelf lives and other desirable characteristics. Genes cannot be made; hence engineering depends on the availability of a broad base of genetic diversity from which genes can be obtained. Aesthetic Value  3 Organisms provide recreation, inspiration and spiritual solace. The natural world is a thing of beauty because of its diversity. Ethical Value The strongest ethical consideration regarding the value of organisms is how humans perceive themselves in relation to other species. The traditional view is that humans are masters of the rest of the world subduing and exploiting other forms of life for their benefit. An alternative view is that organisms have intrinsic value, in and of themselves, and that as stewards of the life forms on Earth, humans should watch over and protect their existence. CARIBBEAN AQUATIC ECOSYSTEMS Mangroves Mangroves refer to a plant community which lies between the sea and the land in areas which are inundated by tides. Mangrove trees are the only trees that can survive in salt water. There are three main types found in Jamaica – Red mangroves, Black mangroves and White mangroves. Mangroves provide valuable environmental services that include: protecting the coastline from erosion and reducing damage from hurricanes; protecting the quality of coastal water by diluting, filtering and settling out sediments, excess nutrients and pollutants; promotes sediment deposition by slowing the movement of storm water; and providing habitat, nursery, breeding and fishing grounds for many species of fish, invertebrates and plants. Mangrove forests are threatened by: excessive siltation and sedimentation; major oil spills; reduction in fresh water inflows and alteration in flushing patterns; deforestation; and dumping up and filling in of mangroves to build hotels and housing schemes (TNC, 2023). Additional information on mangroves Seagrass Beds Seagrasses are submerged marine plants occupying shallow coastal waters. These plants require sunlight to survive and therefore need clear, shallow water through which sunlight can penetrate. The three species dominating the tropical western North Atlantic and Caribbean coastal environments are turtle grass (Thalassia testudinum), manatee grass (Syringodium filiforme)and shoal grass(Halodule wrightii). Seagrasses: habitat and nursery grounds for species; stabilize the sediment and prevent turbidity which would otherwise affect the health of coral reefs usually found adjacent to seagrass beds; reduce wave action; and absorb some of the nitrates and phosphates in the water from land run-off, which reduces the amount reaching adjacent coral reefs. By virtue of being close to the coastline, which over the past decades are becoming more industrialized, seagrass beds are threatened by:  4 the release of excess nutrients (nitrates and phosphates) into coastal waters; the removal of seagrass beds by dredging for construction; propeller damage caused by boating activities; anchoring; deployment of moorings; and fishing and recreational sports (Reynolds, 2018) Additional information on seagrasses Coral Reefs Coral reefs are collections of biological communities which represent some of the most diverse in the world. Corals are tiny plant-like animals that depend on clean, clear, warm, shallow sea water to survive. The coral animals require light for the large number of symbiotic algae, known as zooxanthellae, that live and photosynthesize in their tissues. Corals live in colonies consisting of many individuals, each of which is called a polyp. They secrete a hard calcium carbonate skeleton, which serves as a base or substrate for the colony and provides protection. Coral reefs grow slowly, as coral animals build on the calcareous remains of organisms before them. There are three different types of coral reefs: fringing, barrier and atoll. Coral reefs are important to the Caribbean because they: provide habitat for marine creatures; are a source of food; have commercial value such as being a resource for tourism; control carbon dioxide levels in the ocean; protect coastlines from wave action; have medicinal value; provide sediments for white sand beaches; and are a nursery and breeding ground for many aquatic species. Coral reefs are threatened by: disease; tropical storm damage; wave action; warmer ocean temperatures caused by global warming and thermal pollution (dumping of hot water into oceans by industrial activities); ocean acidification associated with increased carbon dioxide levels; unsustainable fishing methods, including overfishing, dynamite fishing and spear fishing; and pollution from run off, oil spills and sediment (NOAA, n.d.) Additional information on coral reefs. ABIOTIC FACTORS: WEATHER AND CLIMATE Weather refers to the conditions in the atmosphere at a given place and time. Climate comprises the average weather conditions that occur in a place over a period of years. The two most important factors that help to determine an area’s climate are temperature and precipitation. Precipitation refers to any form of water such as rain, snow, sleet or hail that falls to the Earth from the atmosphere. Earth has many different climates, and because each is relatively constant for many years, organisms have adapted to them. Living organisms have adapted to different climatic conditions (temperature, light, moisture) forming communities of plants, animals and soil organisms in particular areas. Consequently, some parts of the earth have similar biotic and abiotic factors covering a large area. This creates a typical ecosystem in that area and these major ecosystems are called biomes.  5 BIOMES A biome is a large, relatively distinct terrestrial region characterised by similar climate, soil, plants, and animals regardless of where it occurs in the world. There are several biome classification systems. Some scientists have included aquatic ecosystems as biomes. However, in this module the term is restricted to terrestrial systems. The system used in this module classifies biomes into eight major groups. These are the tundra, taiga, , temperate deciduous forest, temperate grassland, chaparral, desert, savannah and tropical rainforest (Fisher, 2023). Tundra – this is the northernmost biome. It is characterised by permafrost (layer of permanently frozen soil), by low growing vegetation and by a very short growing season. Taiga – or boreal forest, lies south of the tundra and is dominated by large conifers. Temperate deciduous forest – occurs where precipitation is relatively high and is dominated by broad-leaved trees that lose their leaves with the seasons. Temperate grasslands – have annual fluctuations in temperatures with hot summers and cold winters, producing specific growing periods. Chapparal – characterised by thickets of small-leaved evergreen shrubs and trees and a climate of wet, mild winters and very dry summers. Savannah – have widely scattered trees interspersed with grassy areas. Deserts – found where there is little precipitation and have communities that are specially adapted for water conservation. Tropical rain forest – found in Central and South America, Africa and Southeast Asia, and covers 6% of the earth’s land area. Occur where temperatures are warm throughout the year and precipitation occurs almost daily. Yearly precipitation is 125-660 cm. These areas have highly weathered, mineral poor soils. It is rich in species diversity with no single species dominating the biome. Trees form a dense multi-layered canopy. Deforestation is a major problem in tropical rain forests. In 2022 10.2 million acres of primary rainforest was lost globally. 40% of that tree loss occurred in Brazil, which was then followed by the Democratic Republic of Congo and Bolivia. Deforestation, which may be caused by the clearing of land for agriculture, or to provide firewood and charcoal (Andreoni, 2023). SPECIES ENDANGERMENT AND EXTINCTION Threatened Species: A threatened species is any species of animal, plant, fungi etc. which is vulnerable to extinction in the near future. According to the International Union for the Conservation of Nature (IUCN ), the leading authority on the world’s threatened species there are three categories of threatened species based on the degree to which they are in danger of extinction. These include: 1. Vulnerable Species – these are the least critical in terms of endangerment. These species are face a very high risk of extinction in the wild (IUCN, 2023a) e.g. Jamaican Yellow-Billed Amazon parrot, cheetah, lion, polar bear, giant panda, komodo dragon. Vulnerability is usually caused by habitat destruction or complete habitat loss. 2. Endangered Species – these are species which face a very high risk of extinction in the wild (IUCN,  6 2023a), e.g. Giant swallowtail butterfly, Jamaican Black-Billed Amazon parrot, blue whale, tiger, Tasmanian devil. These species are in danger of extinction due to their relatively few numbers due to environmental changes, increased predation pressure and/or habitat destruction. According to the IUCN approximately 11% of the species listed on the IUCN Redlist are endangered (IUCN, 2023b). 3. Critically Endangered Species – these species face an extremely high risk of extinction in the wild (IUCN, 2023a) e.g. Jamaican Iguana, Vaquita. This is the highest risk category according to IUCN nomenclature. Critically endangered species have also been described as those whose population numbers have decreased, or will decrease by 80%, within three generations. Extinct species: A species that no longer survives anywhere in the world. A species is not considered to be extinct until extensive surveys are done to ensure that no individual of the species may be found on earth. Some species which are thought to be extinct but there is not yet certainty, are still categorized as “critically endangered”. The IUCN has put in place two categories of extinct: “extinct” and “extinct in the wild”. The latter suggests that there are some individuals of the species in question in captivity but none may be found in the wild. Mass Extinction: Refers to certain periods in the earth’s history (5 to 6 times) during which numerous species disappeared during a relatively short geological time period. Range: Refers to the particular area in which a species is found. Characteristics of Endangered Species i. Occupy an extremely small (localised) range This makes them particularly prone to extinction if their habitat is altered. If animals have adapted to only living in a specific area then if that habitat is disturbed they may not be able to migrate to other areas and there are no other individuals in their species that can re-populate the site from other areas. E.g. the vaquita is a marine mammal that can only be found in the northern end of the Gulf of California. Source:https://en.wikipedia.org/wiki/Vaquita#/media/File:Cetacea_range_m ap_Vaquita.PNG ii. Require a large territory to survive Some species require a large territory to survive and may be threatened with extinction when all or part of their territory is modified by human activities. A species’ territory is the area that is defended by an individual, or a group of individuals, within the same species. If their habitat is encroached upon by humans and becomes fragmented, then fewer individuals can be accommodated because resources have diminished  7 and there is not enough space to accommodate the territories needed. E.g. male tigers need a territory of between 60 to 100 km2. iii. Living in isolation Populations that live in isolation (e.g. on an island, separated by mountain ridges, streams, artificial selection) are unable to mix with other populations of the same species. As they evolve and adapt to their environment, they can develop their own characteristics and may eventually become new species. Since they live in isolation they are only able to reproduce with individuals within their own population, which may result in limited genetic variability. While their adaptations might allow them to do well in the environment that they are in, it might also make them vulnerable to new threats such as competitors, predators, climatic changes and disease since their population cannot be replenished by the migration of new individuals, and there is limited genetic variability within their population. iv. Low reproductive rates Organisms that invest a lot in caring for few young may also be more susceptible to becoming endangered. For example, female blue whales produce a single calf every other year. Since they’re producing very few young, it may take a long time for the population to recover should something impact it. v. Low reproductive success If only a few of your young survive, regardless of the number produced, then you become more susceptible to being endangered. For example, a turtle may lay 200 eggs in a nest. However, only 1 in 1000 may survive. vi.Breed only in specialised areas If you have very specific breeding habitats, then if they are destroyed or disturbed this could have serious consequences for the species. For example, sea turtles tend to nest on the beaches where they were born. If these beaches are disturbed then they won’t nest. vii. Highly specialised feeding habits If organisms have very specialised diets, then if that diet is affected, it will reduce the animal’s ability to survive. For example, the giant panda only eats bamboo. In order for a species to survive its members must be present within their range in large enough numbers for males and females to mate. The minimum population density and size that ensures reproduction success varies from one type of organism to another. If population density and size falls below a critical minimum level the population declines, becoming susceptible to extinction. Endangered and threatened species represent a decline in biodiversity, because as their numbers decrease their genetic variability is severely diminished. To be more informed about endangered species and their protection visit the following links https://www.worldwildlife.org/species/ https://www.iucnredlist.org Human Causes of Species Endangerment and Extinction Habitat Destruction -Most species facing extinction today are endangered because of the destruction of habitats by human activities. Even habitats that are left undisturbed are degraded by human produced acid rain, ozone depletion, and climate change.  8 Biotic pollution is the introduction of a foreign or exotic species into an area where it is not native. This often upsets the balance among the organisms living in that area. The foreign species may compete with native species for food or habitat or may prey on them. Humans are usually responsible for biotic pollution. E.g. lionfish, mongoose Hunting – Sometimes species become endangered or extinct as a result of deliberate efforts to eradicate or control their numbers. Many of these species prey on game animals or livestock. In addition to predator and pest control, hunting is done for three other reasons: Subsistence hunting – kill animals for food Sport hunting – kill animals for recreation Commercial hunters – kill animals for profit CONSERVATION BIOLOGY This is the study and protection of biological diversity. It includes two types of efforts that are being made to save organisms from extinction: In situ conservation – this includes the establishment of parks and reserves. It concentrates on preserving biological diversity in nature. Restoring damaged or destroyed habitats. Ex situ conservation – this involves conserving biological diversity in human controlled settings e.g. breeding of captive species in zoos and the seed storage of genetically diverse plant crops. Special techniques such as artificial insemination and embryo transfer are also examples. TUTORIAL QUESTIONS 1. Differentiate between species biodiversity, genetic biodiversity and ecosystem biodiversity. 2. Explain why it is important to maintain biodiversity. 3. a) What is a “threatened species”? b) Three main categories of threatened species exist. State these categories and differentiate between them. 4. Describe the characteristics of endangered species using examples in your descriptions. 5. Discuss ways in which biodiversity can be protected. 6. a) Describe the main causes of extinction and endangerment of species? b) Differentiate between ex situ and in situ conservation providing advantages and disadvantages of each conservation method. c) Provide examples of situations where in-situ conservation would be the more viable, advantageous conservation option i.e. advantageous to the species in question. Do the same for ex-situ conservation. 7. Differentiate between weather and climate. Which characteristic(s) of climate determine the nature of the biome formed? 8. State the major characteristics and the general geographical locations of the following biomes of the earth: Tundra Taiga Tropical rainforest Desert  9 LITERATURE CITED Andreoni, M. (2023, June 27). Despite global pledges, tree loss is up sharply in tropical forests. New York Times. https://www.nytimes.com/2023/06/27/climate/trees-tropical-forests-deforestation.html Brillon, K. (2022, June 22). Pyrethrin spray: An organic pesticide with history. Retrieved April 26, 2024 from https://www.epicgardening.com/pyrethrin-spray/ Brinson Brothers. (2020, August 3). How is insulin made by biotechnology. Biotech Health. https://biotechhealth.com/how-is-insulin-made-by-biotechnology/ Fisher, M. (n.d.). Terrestrial Biomes. Environmental Biology. https://pressbooks.umn.edu/environmentalbiology/chapter/terrestrial-biomes/ Galan, N. (2019, April 26). What the benefits of neem? Medical News Today. https://www.medicalnewstoday.com/articles/325048 Gruber, K. (2017). Agrobiodiversity: The living library. Nature 544, S8–S10. https://doi.org/10.1038/544S8a Ickowitz, A., McMullin, S., Rosenstock, T., Dawson, I., Rowland, D., Powell, B., Mausch, K., Djoudi, H., Sunderland, T., Nurhasan, M., Nowak, A., Gitz, V., Meybeck, A., Jamnadass, R., Guariguata, M.R., Termote, C. & Nasi, R. (2022). Transforming food systems with trees and forests. The Lancet Planetary Health 6(7), E632-E639. https://doi.org/10.1016/S2542-5196(22)00091-2 International Union for the Conservation of Nature. (2023a). The IUCN red list categories and criteria. https://www.iucnredlist.org/en#:~:text=The%20IUCN%20Red%20List%20Categories%20and%20Criteria %20are,Critically%20Endangered%2C%20Extinct%20in%20the%20Wild%20and%20Extinct. International Union for the Conservation of Nature. (2023b). Summary Statistics. Table 3: Number of species in each IUCN Red List Category by kingdom and class. https://www.iucnredlist.org/statistics Lowe, H., Steele, B., Bryant, J., Fouad, E., Toyang, N. & Ngwa, W.(2021) Antiviral activity of Jamaican medicinal plants and isolated bioactiv compounds. Molecules, 26(3). 607. https://doi.org/10.3390/molecules26030607. National Oceanic and Atmospheric Administration. (n.d.). The importance of coral reefs. Retrieved April 26 , 2024 from https://oceanservice.noaa.gov/education/tutorial_corals/coral07_importance.html Reynolds, P.L. (2018, April). Seagrass and Seagrass Beds. Smithsonian National Museum of Natural History. Retrieved April 26, 2024 from https://ocean.si.edu/ocean-life/plants-algae/seagrass-and-seagrass-beds Ritchie, H., Rosado, P. & Roser, M.. (2019). Meat and Dairy Production. Our World in Data. Retrieved April 26, 2024 from https://ourworldindata.org/meat-production The Nature Conservancy. (2023, April 5). The importance of mangroves. Retrieved April 26, 2024 from https://www.nature.org/en-us/about-us/where-we-work/unit0ed-states/florida/stories-in-florida/why- mangroves-important/. Veeresham, C. (2012). Natural products derived from plants as a source of drugs. Journal of Advanced Pharmaceutical Technology and Research 3(4): 200-201. https://doi.org/10.4103/2231-4040.104709  10 Originally Compiled By: Raymond Martin First Revision Done By: Nikki Bramwell, Raymond Martin and Damian Nesbeth Second Revision Done By: Christine O’Sullivan, May 2012 Third Revision Done By: Christine O’Sullivan, January 2016 Updated By: Christine O’Sullivan, June 2021