Biodiversity and Evolution PDF

BIODIVERSITY AND EVOLUTION Biodiversity - is the term used to describe the number and variety of life found on Earth. Biodiversity has three types: genetic, species, and ecosystem.  A. Genetic diversity - pertains to the variation of genes within species. Examples different breeds of dogs, di...

BIODIVERSITY AND EVOLUTION Biodiversity - is the term used to describe the number and variety of life found on Earth. Biodiversity has three types: genetic, species, and ecosystem.  A. Genetic diversity - pertains to the variation of genes within species. Examples different breeds of dogs, different varieties of rose flower, rice, mangoes etc.  B. Species diversity - pertains to the variety and abundance of species within a region.  C. Ecosystem diversity - is the variation among groups of organisms in different physical settings.  Ecosystem - consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows.  All parts of the ecosystem are interacting with one another. If one of its components experienced changes and it doesn’t adapt to its new environment or situation it may probably die and lessen in numbers.  Population - pertains to the number of organisms of the same species living in the same region.  Communities - are composed of different organisms living in the same region.  Limiting factors - are usually described as lack of particular resources like the availability of food, water, and space.  Carrying capacity - Increasing the number of population size that an area can support. It is the size of a biological species that can be sustained in a specific environment, given all the available resources. If the carrying capacity reaches its maximum point, the organism in that area will die because not all of their needs can be met.  Endangered - When the number of species decreases in size, and only a few remain.  Example of an endangered species are Tamaraw, Tarsier Philippine Eagle, Philippine crocodile, turtles and etc.  Threatened - If animals of a particular species are vulnerable at risk in terms the number of population of its kind.  Examples of Visayan Warty pig, Tamaraw in Mindoro, Philippine eagle etc.  Extinction - happens if the last member of that species is gone like dinosaurs.  Examples of extinction Natural Causes of Species Extinction  1.Climate change- the sudden changes in the earth’s temperature.  2.Land Development- conversion of land into residential area or building.  3. Acid precipitation- is a result of air pollution.  4. Diseases/Epidemic- infectious diseases or virulent infectious diseases cause the change in biological populations.  5. Meteoric impact/Cosmic radiation- extinction happens when a massive asteroid or meteor hits the surface of the earth.  6. The spread of Invasive species- it can change the abundance of diversity or the food web in an ecosystem by destroying and replacing its natural value and number. Man-Made Causes of Species Extinction  1. Deforestation- illegal logging, kaingin, farming.  2. Pollution- either air or water pollution.  3. Destruction of Coastal Resources - this is caused by using dynamite in fishing, muro-ami, and the conversion of beach into residences, and overharvesting of fishes.  EVOLUTION - describes the gradual change of organisms from one state to another. It deals with the first appearance of organisms and studies how they survive and change through the course of time. Geologists constructed a timetable of the earth’s history which is called geologic timescale. Geologic timescale - is a timetable of the earth’s history. In this scale, the earth’s history is divided into major divisions called eras.  A. Paleozoic era (prehistoric life) – the existence of marine invertebrates; the development of marine life.  B. Mesozoic era (middle life) – the existence of largest creatures.  C. Cenozoic era (recent life) – the existence of warm-blooded animals and humans.