Ecology PDF - Biological Diversity

Ecology: is the study of relationships between living organisms, between organisms and their environment. Population: A group of organisms that are the same species that live in the same area at the same time. Ecosystem: a community and its abiotic(non-living) environment. Community: A gr...

Ecology: is the study of relationships between living organisms, between organisms and their environment. Population: A group of organisms that are the same species that live in the same area at the same time. Ecosystem: a community and its abiotic(non-living) environment. Community: A group of population that interacts with each other in the same area Species: A group of organisms that can interbreed to produce fertile offspring Habitat; Is the environment in which species live Fertile offspring: When the youngest generation grows to reproduce another generation Breed: to have babies Interbreed: fusion with different members of closely related species that have a babie(hybrid) - If two members of closely related species interbreed and produce offspring the hybrid would be sterile Heterotrophs: Are the ones that feed on living organisms by ingestion - Heterotrophs that ingest other organisms living or recently killed obtain their organic molecules, they are named Consumers. Consumers: Have a range of different food sources and feed mechanisms. Autotrophs: These are organisms that produce their own food from organic molecules, therefore are known as Producers - 2 producers: Photoautotrophy(photosynthesis occurs in plants and in some bacteria with sunlight) - Chemoautotrophy: bacteria and other organisms that involve the use of energy to released by inorganic chemical reaction to produce food. Herbivores(zebra, deer, aphids): feed on producers Omnivores(chimpanzee, mouse): feed on both producers and consumers Carnivores(lion, snake, ladybirds): feed on consumers Scanvengers(hyenas, vulture crows): Are specialized carnivores that feed on dead and decaying animal - All organisms require organic molecules like amino, acids, to carry out the functions of life, for example,e metabolism, growth, and reproduction. Mixotrophs: Are few plants and algae that have a combination of different modes of nutrition Example: Euglena is a type of algae that will photosynthesis(autotrophs) but can also ingest particles of food by phagocytosis(heterotrophs) Decomposers: Are organisms, especially bacteria, a fungus that digest things like dead plants or animals and converted into humus. Faciliate the breakdown or organic material - Detritivores:ingest non-living organic matter(earthworms, woodlice) - Saprotrophs: lives in or on living organic matter, secreting digestive enzymes(breakdown the food so can use the nutrients) on to the organic matter and absorb the products of digestion Biomes: Is a large community of plants and animals in a specific geographical region. 6 major biomes: - Dessert - Tundra  - Tropical rainforest - Temperate forest - Grassland - Hot dessert 7 abiotic factors that determinants terrestrial biome distribution: - Temperature - Water - Ph - Rainfall - Air - Soil - Sunlight Limiting factors: Is an environmental condition that controls the rate at which a process(population growth) can occur. Biotic limiting factors: include interactions between organisms such as competition and predators. - Animals and plants have similar limiting factors the biotic ones that is competition, food sources, etc, and the ones that don´t have in common like abiotic ones(temperature, water) 5 limiting factors that plants include: - Light - Water - Nutrients - Carbon dioxide - temperature 4 limiting factors on animals - Food - Space - Mate - water Halophytes: Are the plants that can grow with high water salinity or in soil. Glycophytes: Are the plants that do not tolerate the salt - High concentration of salt in soil makes harder for the roots to extract water, due to the osmotic effect. Law of tolerance: States organism and population to have a certain minimum, maximum and optimum environmental factors that determine sucess. - Range of intolerance is between the critical minimal and maximum limits of environmental factors affecting organism - Optimum zone of tolerance: Is the central portion, where conditions are at the maximum and exits growth, abundance, and survival. - Zone of stress: side of the optimal zone, fewer individuals occur and survival is low, organisms are unable to reproduce. - Zone of intolerance: beyond critical minimal and maximal limits of environmental factors: Organisms can't occur here. Factors affecting distribution of species: - Plants: temperature, water, light, soil ph - Animals: temperature, water, territory, food supply Coral reefs: - Are built with coral polyps as they secrete layers of calcium carbonate beneath their bodies - The corals that build reefs are known as “hard” or “reef-building” corals. - Soft corals, such as sea fans and sea whips, do not produce reefs. 6 Types of animals and plants that contribute on coral reefs: - Algae - Seawood - Sponges - Sediment - Mollusks - Oysters When these organisms die, they serve as a foundation for new corals. - Some coral species can regenerate and rebuild their skeletons, making them resilient to environmental stress. 5 Conditions that are required for coral reef formation: - Water depth - Ph - Salinity - Water clarity - Temperature Adaptions that coral reef develop to survive: - Camouflage  - Symbiotic relationship - Protective covering - Stringers and spines - Reproductive strategies Population ecology: Exponential growth curve: this pattern produces a J- J-shaped curve and occurs in an ideal, unlimited environment Sigmoid curve: his pattern produces an S-shaped curve and occurs when environmental pressures slow the growth rate. This model is sed to model functions that at first increase gradually, then more rapidly in the middle, and in slowly at the end. This model is observed in populations with scarcity of food materials. - All environments have a finite carrying capacity(K), beyond this limit, the population can no longer increase overall. Populations are affected by 4 main factors: - Immigration(positive): increases in population size from external populations - Natality(positive): increases to population size through reproduction - Mortality(negative): decreases the population size because of death(predators) - Emigration(negative) :Decreases population size as a result of loss to external populations Population size=(inmigration+natality) - (mortality+enmigration) Population growth follows a sigmoidal curve: Exponential phase: Is the best because I+N is bigger than E+M meaning that there is abundant resources, low competition and high reproduction. Transition phase: The population continues to grow,and competition increases as resource availability is reduced. I+N is bigger than E+M, but Natality starts to fall, and mortality starts to rise, leading to a slower rate of population increase. Plateau phase: increases mortality, and limited resources, while the population size may not be static, it will oscillate around the carrying capacity. Top-down factors are pressures applied by other organisms at higher trophic levels(predators) Bottom-up factors are those that involve resources or lower trophic levels(autotrophs/producers) Lincoln index equation: Population size= n1 x n2/n3 Biodiversity Biodiversity or biological diversity is the variety of living organisms including plants, animals, and microorganisms. 3 levels of biodiversity: - Genetic diversity: is the diversity seen in the genes(alleles) within a population of species - Species diversity: the number and types of species that exist during a specific amount of time. - Ecosystem diversity: variety in ecosystems in a given area, terrestrial and aquatic. Species diversity Richness: the number of different species in an area Evenness: the number of individuals of each species is similar across different species. If the number of individuals varies the evenness is low. } - An indicator species is an organism that used to assess a specific environmental condition. - Indicator species have a limited range of tolerance Anthropogenic factor: environmental change caused or influenced by people, either directly or indirectly. - IN-situ (in it natural habitat) - EX-situ (away from its natural habitat) Testing for association between species Positive association: species found in the same habitat Negative association: species occur separately indifferent habitats No association: species occur as frequently apart as together Chi-squared test Expected value= (row total)(column total)/ grand total