BIODIVERSITY Biodiversity is a term used to describe how varied living things are in an ecosystem. The more diverse the ecosystem, the more stable it is. Biodiversity is used describes how diverse organisms in an area. It is a measure how many different species live in an area. An ecosystem with high biodiversity has many different species of organisms. An ecosystem with low biodiversity does not have many different species of organisms. Biodiversity is the variety of life forms in an ecosystem that describes how varied living things are in a specific area. It is very important since it sustains through the flow of energy the food web on earth and contributes to environmental stability. Biodiversity is the variety of life on earth and the essential interdependence of all living things. Biological diversity, includes all organisms, species, and populations; the genetic variation among these; and all their complex assemblages of communities and ecosystems. It also refers to the interrelatedness of genes, species, and ecosystems and their interactions with the environment. An ecosystem can be small like an aquarium or a small pond in your backyard, with only a few organisms interacting, or it may be large, like a forest with lots of organisms interacting. There are two types of ecosystem: man-made and natural ecosystem. When we speak of natural ecosystem, we are referring to those areas with little or no human intervention. A forest is a natural ecosystem if it remains to be unchanged by human activities. Other natural ecosystems include the oceans, the seas and the rivers. Organisms are part of biodiversity and may be economically and ecologically valuable. Their products are a source of food, medicine, clothing, shelter and energy. They are important in maintaining the balance in the ecosystem as they perform their specific roles. Biodiversity describes how various are organisms’ existence in different ecosystems. Organism can be economically and ecologically valuable. These organisms are also essential in keeping the ecosystem stable as they perform their specific roles. Biodiversity is vital as it sustains through flow of energy the food web on this planet and contributes to environmental stability. Stability of an ecosystem can be described as the resilience to resist changes that will occur in the environment. There are many changes that occur in the environment, and these changes may severely reduce biodiversity and will result in instability of the ecosystem. The value of species can be divided into various categories: 1. DIRECT ECONOMIC VALUE Species are sources of the basic needs of human such as, food, clothing, shelter, medicine and energy. For example, rice plant is the primary food of Filipino. Cotton is use to make clothes. Malunggay rich in vitamins; it is used to make medicines. 2. INDIRECT ECONOMIC VALUE Species if there are benefits produced by the organism without using them. For example, tree planting to prevent landslide and soil erosion and absorbs carbon dioxide in the air. 3. AESTHETIC VALUE Lot of species provides visual or artistic enjoyment, like forested landscape and the calming beauty of a natural park; or they may be used for spiritual meditation like the Prayer Mountains. LEVELS OF BIODIVERSITY 1. Genetic Diversity - different genes & combinations of genes within populations. Genetic diversity is all the different genes contained in all individual plants, animals, fungi, and microorganisms. It occurs within a species as well as between species. 2. Species Diversity- organisms that have the potential to interbreed in nature and produce viable, fertile offspring. A number of different species represented in a given community. Population are a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring. Species diversity is all the differences within and between populations of species, as well as between different species. 3. Ecosystem Diversity-variation in the ecosystems found in a region. Ecosystem diversity is all the different habitats, biological communities, and ecological processes, as well as variation within individual ecosystems. Species diversity is defined as the number of species and abundance of each species that live in a location. The number of species that live in a certain location is called species richness. Species diversity is the number of different species that are represented in a given community. Species diversity is the number of different species that are represented in a given community (a dataset) incorporates both the number of species in a community (species richness) and the evenness of species abundance. The effective number of species refers to the number of equally abundant species needed to obtain the same mean proportional species abundance as that observed in the dataset of interest. Species is described as largest group of organisms capable of interbreeding and producing fertile offspring. Diversity as a state of being diverse or variety; a range of different things. 3 TYPES OF SPECIES: Endemic species - is one whose habitat is restricted to a particular area; often endangered - differs from “indigenous,” or “native,” (although it occurs naturally in an area, is also found in other areas.) Exotic Species -is any species intentionally or accidentally transported and released by man into an environment outside its present range. -most severe agents of habitat alteration and degradation, and major cause of the continuing loss of biological diversity throughout the world. Cosmopolitan Species -Pertinent or common to the whole world. Cosmopolitan distributions can be observed both in extinct and extant species. In an ecosystem, there are various interactions between species that contribute to the structure of the community. This interaction may be categorized into four types: competition, predation, herbivory and symbiosis. Adaptation refers to the ability of an organism to survive and reproduce in an environment. This may involve changes in behavior or physical structure to survive. For example, if we take a street dog (that lives in a tropic place) in Alaska (cold country), it will grow thicker fur to survive cold temperature. Likewise, when a dog in a cold country brought to the tropics, it will shed its fur to adapt to the warm climate. Variation increases the chance of survival. Organisms with the most desirable traits would likely survive environmental changes and gradually become better suited to survive in a given environment; this is called adaptation. The differences among individuals in a population that improve the species' fitness. These adaptations can be physical, chemical, or behavioral. Camouflage and mimicry are two forms of physical adaptation. Camouflage: Structural adaptation that enables an individual to blend with its surroundings, and that allows an individual to avoid detection by predators. Occurs when an individual “blend” into the environment in the eyes of a potential predator. Mimicry: A phenomenon in which an individual gain some sort of survival advantage by looking like an individual of another (often more harmful) species. Is present when one species has evolved to look like another species in a way that will provide some advantage. The best-known examples of mimicry are those in which a species mimics another that is toxic or harmful to a potential predator. Camouflage and mimicry are both adaptations because they increase the likelihood of an individual evading predation long enough to reproduce. Bivalves also provide good examples of camouflage and mimicry. The spines on the shells of Spiny Oysters (family Spondylidae) provide crevices in which algae, sponges, and other epibionts Epibiont is an organism that lives on the surface of another living organism. Can settle and grow to cover and camouflage the shell. With time, this growth helps the Spiny Oyster to “disappear” on the surface of the reef, lowering the threat of predation from top level predators such as fish. Octopuses and squid (both cephalopods, and close relatives of bivalves) are the “camouflage champions” of the mollusk. In an article published by usaid.gov. bwiser, 2016, Philippines is considered as one of the 17 mega biodiverse countries in the world containing 2/3 of the Earth’s biodiversity and 70% of the world’s plants and animal species. It is geographical isolation with an area of 300,000 square meters and tropical climate made it a perfect place to inhabit a variety of life forms. The two basic reasons why a population’s size increases, or decreases are the birth rate (natality) and the death rate (mortality). If the birth rate is greater than the death rate, a population will increase. If the birth rate is slower than the death rate, the population will decrease. A population is a group of living things within a certain area that are all of the same species. Several different populations may be found in a community. Populations can be of the same size but they may have different densities. Population density is defined as the number of organisms per unit area. A major component of modern ecological research focuses on understanding what influences the abundance of organisms within a population, and why this abundance changes over time. A term called population dynamics refers to how populations of species change over time. The study of a species’ population dynamics usually seeks to answer questions such as: What explains the average abundance of a population? What causes fluctuations in the abundance of a population? When conditions are ideal for growth and reproduction, a population will experience a rapid increase in size. Initially the population grows slowly, but the larger the population gets, the faster it grows. As more offspring survive and reproduce, even more offspring are born. The graph illustrates a population growth curve of this nature. Population Growth Curve Population growth is based on four fundamental factors: birth rate, death rate, immigration, and emigration. Using these factors, the formula in determining population growth is as follows: Population growth= (births+ immigrants) - (deaths+ emigrants) If the population growth is less than zero, this simply means that there are more deaths and emigrants (organisms that leave the area) in the population than there are births and immigrants (organisms that arrive new to the area). If this is the case, the size of the population will begin to decline. Ecologists regularly monitor the number of organisms in many populations because every population can either potentially grow or decrease. They also observe the indicators that manifest if some potential problems in the habitat of the organisms may arise. Each condition will give a warning to the ecologists if something is off. An essential question though is why do population sizes have a tendency to increase or decrease? There are many factors that can cause a population’s size to change and this is the reason why there is a need to understand the basic reason why a certain population increases or decreases. Population of any organisms (humans, animals or bacteria) will continue to grow if more organisms are being developed (genetically modified organisms) or born, than are dying. There are two main ways that individuals can be added to the population. The first way is through the births of new individuals. The way we measure additions of this type is with the natality rate (also called the birth rate), which is the number of births per 1,000 individuals per unit of time, usually per year. The second way in which individuals are added to the population is through immigration. This is the permanent arrival of new individuals into the population. These individuals are of the same species as the rest of the population, and they can increase the size of the population as they join the group. On the flip side, we have two main ways that individuals can leave a population and reduce its size. First is through the deaths of individuals. We measure this with the mortality rate (also called the death rate), which is the number of deaths per 1,000 individuals per unit of time. Again, this time is usually measured by year. Second, individuals may leave through emigration. This is the permanent movement of individuals out of a population. These may be juveniles who are heading out on their own, or it may be adults leaving the group for some other reason such as overcrowding or searching for new areas for food and shelter. Take note that if the birth rate is greater than the death rate, a population will grow. On the other hand, if the death rate is greater than the birth rate, then the population will decrease. The largest population of a species that a particular environment can support is known as the CARRYING CAPACITY. The carrying capacity of the environment varies at different times. Sometimes, when resources such as food and water are more abundant, a population can increase in size. At other times, when there is less food, water, and shelter, a population can decline. These population fluctuations occur over time, but the carrying capacity represents an average series of ups and downs. If you draw a line through the middle of the population fluctuations, that line represents the carrying capacity of that environment for species living in it. As a population grows in an area, a population may experience the effects of increased densities. The maximum population size of species that the environment can sustain is called the carrying capacity which is determined by the amount of available resources (food, habitat, water). In a high population density, there are a lot of organisms crowded in a certain area, while in a low population density, only few organisms are in an area. Differences in population densities in any community may be attributed to limiting factors. Limiting factors limit the size of a population. These factors prevent the growing population of any organism in an area, which will be limited, or stopped at some point. Limiting factors are categorized into two: the density-independent limiting factors and density-dependent limiting factors. Ultimately, when a population grows, it does not grow forever. It will stop at some point, until eventually, the death rate will exceed the birth rate. Basically, the population’s growth is limited by two general factors: density-independent limiting factors and density-dependent limiting factors. If the population’s density does not directly influence changes in population growth, then it is called a density-independent limiting factor. Examples include natural disasters like tropical cyclones, floods, earthquakes and fires. These natural phenomena will stop a population from growing no matter how many organisms are living in a certain place. The same goes for the temperature of an area and the amount of sunlight it receives. If the temperature increases due to global warming, this will cause a decrease in a population’s numbers, no matter how large or small the population was to begin with. Human activities that alter the environment will also decrease the number of organisms in a population, regardless of the size of the population. Density-independent factors, such as temperature or natural disasters, refer to any influences on birth or death rates regardless of the population density (the number of organisms per unit area). If a population’s density is very high, that means there are a lot of organisms crowded within a certain area. If a population’s density is low, this means that there are very few organisms found in an area. Density-independent limiting factors that can stop a population from growing can be such things as natural disasters, temperature, sunlight, and the activities of humans in the environment. Natural disasters such as tropical cyclones, floods, earthquakes and fires will stop a population from growing no matter how many organisms are living in a certain area. As an example, global warming is proven to increase the temperature of an area and the amount of sunlight it receives. This phenomenon can cause a decrease in a population’s number, regardless of how large or small the population was to begin with. This simply means that human activities that alter the environment, global warming for example, can definitely decrease the number of organisms in a population regardless of the size of a population. A factor that regulates a population’s growth and is influenced by population density is called density-dependent limiting factors. Density-dependent limiting factors come into play when a population reaches a certain number of organisms. For example, when a population reaches a certain size, there will not be enough resources (food, shelter, water) for all the organisms. This could cause the population to stop growing when it reaches the maximum number of organisms that can be supported or “carried”, by the environment. This number is known as the population’s carrying capacity in a particular environment. Each population of organisms has a different carrying capacity, depending on the amount of resources available in the area in which it lives. Density-dependent limiting factors, however, are tied to population density. In other words, they change how they can affect the population as the population changes in size. These factors can be biological in nature, such as food, shelter, or other limited resources. This will come into play when the population reaches a certain number or organisms and there is a lack of enough resources (shelter, water, food) for all the organisms. Density-dependent limiting factors are factors that depend on the size of a certain population. If the population is already high, these factors will limit the increase of population size. Such density-dependent limiting factors are the availability of food, water, and space. While density-independent limiting factors are those that limit the size of population regardless of the population number. Some examples are natural disasters, temperature, and sunlight. This event can cause the population to stop growing when it reaches the maximum number of organisms that can be supported by the environment. This number is known as the population’s carrying capacity in an environment. Each population of organisms has a different carrying capacity depending on the amount of resources available in the area in which they live. Each population of organisms has a different carrying capacity depending on the amount of resources available in the area. There is a limit to the number of individuals in a population that an environment can maintain. Before a population reaches it’s carrying capacity, it experiences a period of rapid growth. This period of growth is called exponential population growth. During this period, there are plenty of resources available for all organisms, so more births are recorded than deaths of organisms. When resources are unlimited, populations exhibit exponential growth, resulting in a J-shaped curve. When resources are limited, populations exhibit logistic growth. This is a description of idealized population growth that is slowed by limiting factors. When resources are limited, populations exhibit this type of growth. In logistic growth, population expansion decreases as resources become scarce, and it levels off when the carrying capacity of the environment is reached, resulting in an S-shaped curve. Limiting Factors that Depend on Population Density Illustration Diseases and parasites- infectious diseases and parasites spread faster in densely populated areas. Competition for resources- organisms with better adaptations to obtain (food) resources will be able to reproduce more often, and its population will grow. The organisms that have limited abilities to compete for the resources will not reproduce as often, may not be fit enough to live long, and can cause their population to decrease. Predation- plenty of prey are available, predators will be able to eat sufficiently, thus have energy to reproduce much, and increase their numbers. The population of the prey will begin to decrease as more and more of them are eaten. However, the predator population will eventually reach carrying capacity-there will not be enough prey for all of the predators in the population, since the predators themselves compete for their “prey” resources. As the number of prey decreases, so will the number of predators because there is not enough food to sustain them. Emigration- It occurs when a population approaches its carrying capacity, and individual organisms leave and go to a new area where they can find enough resources for survival and reproduction. This will obviously cause decrease in the amount of organisms in a population. Organisms need a balanced ecosystem. Their number should not exceed in the carrying capacity of their respective environment. This is called sustainable development. THE MEASUREMENT OF BIODIVERSITY Biodiversity is The sum of all biotic variation from the level of genes to ecosystems. The number, variety, and variability of living organisms in a quantified area. Methods to Measure Biodiversity: Species Richness - the total number of given species in a quantified area. Species Evenness - the degree to which the number of individual organisms are evenly divided between different species of the community. Disparity - measures the phenotypic differences among species resulting from the differences genes within a population. Species Rarity - the rarity of individual organisms within a quantified area. Genetic Variability - each population of a species contributes to additional biodiversity due to variations between genes. Biodiversity and the Relationship to Ecosystem Functions - Diverse communities are typically more stable and function more efficiently. - Increase of productivity in an area corresponds with an increase in biodiversity - Ecosystems with high measures of biodiversity are more resistant to invader species. • Biodiversity is the variety of life and can be measured on multiple scales including genetic diversity, species diversity, and ecosystem diversity. • Indices that measure species diversity include species richness (the number of species in a given area), the Shannon diversity index (accounting for richness and proportional abundance of species) and evenness (similarity in the abundances of species). • The location and abundance of animals are determined by the availability of resources and community interactions, such as competition, predation, and human influences. • An ecological niche is the role of an organism in its environment, which includes the conditions under which it can live, what resources it uses, and how it reproduces. • The diversity of an ecosystem, including soil, plant, structural, topographic, and climatic diversity, can positively impact animal species diversity. Threats to Biodiversity and their Implications Biodiversity around the world is threatened by pollution, climate change, and invasive species. A main underlying reason for efforts to maintain biodiversity is based on ecosystem functioning. Ecosystems are made up of many working parts, including primary producers, herbivores, carnivores, and detritivores, all of which contribute to ecosystem function. If species are lost, the ecosystem may collapse. And if the ecosystem collapses, the services that it provides to humans will as well.