Biodiversity lecture 3.pdf

Biodiversity Lecture 5 Dr Hadil Alahdal Lecture outline Concept of biodiversity Distribution of biodiversity Biodiversity and balance of nature Benefits of biodiversity Threats to biodiversity Future of Biodiversity studies  The biodiversity found in genes,...

Biodiversity Lecture 5 Dr Hadil Alahdal Lecture outline Concept of biodiversity Distribution of biodiversity Biodiversity and balance of nature Benefits of biodiversity Threats to biodiversity Future of Biodiversity studies  The biodiversity found in genes, species, ecosystems, and What Is ecosystem processes is vital to sustaining life on earth. Biodiversity and biological diversity or biodiversity is ‘the variety of life’ and refers collectively to variation at all levels of biological Why Is It organization. Important? Biodiversity at different levels Factors affecting Biodiversity Genetic diversity Species diversity Ecosystem diversity Functional diversity  Ultimate source of biodiversity at all levels. 1- Biodiversity The number of genes in organisms ranges over three levels- orders of magnitudes. Genetics Within species the possible number of combinations exceeds the number of individuals present. Measurements of genetic diversity have many theoretical and practical applications Genetics diversity- Genetics- Intra-specific diversity Within populations: optional change of evolutional rate is proportional to genetic variety. Between populations: result from local adaptation. 2- Levels of Biodiversity- species diversity Species richness: the number of species in a given area Speciation Speciation One species splits into two or more species that can no longer breed and produce fertile offspring Geographic isolation Reproductive isolation Biodiversity levels- species Species diversity A set of individuals that can mate and produce fertile offspring 8-100 million species total; likely 10-14 million 2 million species identified A large number of species are going to be extended before they are identified. ~50% in endangered tropical rainforests Biodiversity levels-species They are many species that have barely been described such are viruses, fungi, protists, bacteria and unicellular algae. Other poorly known groups include insects, nematodes, and mites. Most species are not documented Species Diversity Species richness Species evenness Varies with geographic location Species richness declines towards poles Does a community with high species richness have greater sustainability and productivity? Research suggests “yes” Keystone Species Significant role in their food web: large affect on types and abundances of other species in an ecosystem Elimination may alter structure and/or function of ecosystem Pollinators Top predators  Core Case Study: Why Are Amphibians Vanishing? Habitat loss and Pollution fragmentation Climate change Prolonged drought Overhunting Increased ultraviolet Nonnative predators and radiation competitors Parasites 33% of all amphibian species face Viral and fungal extinction diseases https://www.ncbi.nlm.nih.gov/p mc/articles/PMC2829317/ https://www.sciencedirect.com/s cience/article/abs/pii/S00063207 Levels of Biodiversity- Ecosystem Ecosystem: a biological community of interacting organisms and their physical environment. Biome: major collection of different ecosystems with similar characteristics.  Average annual precipitation 100-125 cm (40-50 in.) Levels of Biodiversity- Ecosystem 75-100 cm (30-40 in.) 50-75 cm (20-30 in.) 25-50 cm (10-20 in.) below-25 cm (0-10 in.) Denver Baltimore San Francisco St. Louis Las Vegas Coastal Sierra Great Rocky Great Mississippi Appalachian mountain Nevada American Mountains Plains River Valley Mountains ranges Desert Coastal chaparral Coniferous Desert Coniferous Prairie Deciduous and scrub forest forest grassland forest Different environmental conditions lead to different selective pressures and the development of two different species. Adapted to cold through heavier fur, short ears, Arctic Fox short legs, and short nose. White fur matches snow for camouflage. Northern population Early fox Spreads northward and southward population and separates Adapted to heat through lightweight Gray Fox fur and long Southern ears, legs, and population nose, which give off more heat. Fig. 4-8, p. 68 Functional Diversity Ecological Diversity The biological and chemical processes such as energy The variety of terrestrial and flow and matter recycling needed for the survival of species, aquatic ecosystems found in communities, and ecosystems. an area or on the earth. Genetic Diversity Species Diversity The variety of genetic material The number and abundance of species within a species or a population. present in different communities Fig. 4-2, p. 61  What Roles Do Species Play in an Ecosystem? Ecological Niche (1) Each species plays a specific ecological role called its niche. Species occupy unique niches and play specific roles in an ecosystem Includes everything required for survival and reproduction Water Sunlight Space Temperatures Food requirements  Ecological Niche (2) Generalist species Specialist species Native species Nonnative species How Does the Earth’s Life Change over Time? The scientific theory of evolution explains how life on earth changes over time through changes in the genes of populations. Populations evolve when genes mutate and give some individuals genetic traits that enhance their survival abilities and produce offspring with these traits (natural selection). Provide some examples? How to study biodiversity in older times? Fossils Mineralized and petrified remains Skeletons, bones, and shells Leaves and seeds Impressions in rocks Fossil record incomplete: ~1% of all species Population Changes over Time Populations evolve by becoming genetically different over time Genetic variability – mutations Random changes in DNA molecules in genes Can occur spontaneously External agents: radiation Can create a heritable trait  Natural Selection Adaptive traits - genetically favorable traits that increase the probability to survive and reproduce. Example! Trait – heritable and can lead to differential reproduction Faced with environmental change Adapt through evolution Migrate become extinct Genes mutate, individuals are selected, and populations evolve to be better adapted to survive and reproduce under existing environmental conditions. Example of natural selection in bacteria Adaptation through Natural Selection Has Limits Humans are unlikely to evolve and have skin that’s not harmed by UV radiation 1. Desired trait must already be in the gene pool. 2. Must have high reproductive capacity so adaptive traits can be spread rapidly Three Myths “Survival of the fittest” does not mean “survival of the strongest” about Evolution through Natural Selection Organisms don’t develop traits just because they would be useful: giraffes and long necks Refuted There is no grand plan of nature to create more perfectly adapted species – no trend toward genetic perfection How Do Geological Processes and Climate Changes Affect speciation? Tectonic plate movements, volcanic eruptions, earthquakes, and climate change have shifted wildlife habitats, wiped out large numbers of species, and created opportunities for new species. Species richness usually gradually increases over geological time.  Plate Tectonics Locations of continents and oceans determine earth’s climate The movement of continents allows species to move and adapt Earthquakes and volcanoes affect biological evolution by separating populations of a species and allowing new species to develop Earth’s Long-Term Climate Changes Cooling and warming periods – affect evolution and extinction of species Change ocean levels and area Glaciers expanding and contracting Climate changes Opportunities for the evolution of new species Many species go extinct  18,000 Northern Hemisphere Modern day years before Ice coverage (August) present Legend Continental ice Sea ice Land above sea level Fig. 4-7, p. 67 Current Human Activities Affect Biodiversity? Human activities decrease the earth’s biodiversity by: Causing the premature extinction of species, and by destroying or degrading habitats needed for the development of new species.  Biological extinction Entire species gone Local extinction Extinction All members of a species in a specific area gone (1) Endemic species vulnerable to extinction Background extinction rate of extinction Speciation generally more rapid than extinction Extinction (2) Mass extinction Earth took millions of years to recover from previous mass extinctions Cretaceous-tertiary extinction 65 million years ago Balance between speciation and extinction determines biodiversity of earth Humans cause premature extinction of species Unfortunately, we are at another mass extinction period due to the large number of populations going extinct. Future of Biodiversity in Saudi Arabia Summary Diversity has different levels Each level has a number of factors to manipulate each level All levels are interconnected Future directed programs are essential to avoid massive loss of diversity References file:///C:/Users/al_ma/Downloads/Biodiversity-AnIntroduction.pdf "What is biodiversity?" (PDF). United Nations Environment Programme, World Conservation Monitoring Centre.