Extinction

• The Philippines was named one of the world’s biodiversity hotspots in 2000.
• endemic species


  A species that can only be found in a certain location and not elsewhere
• The Philippines’ surrounding seawater is also considered a major center of marine biodiversity globally for having one of the highest concentrations of marine species in an area.
• In line with the large number of different species present in the Philippines, most of these organisms tend to be endemic in the country. Since their distribution is highly limited, and they are not present anywhere else in the world, they tend to become an endangered species due to environmental disturbances and human activities.
• Endangered species


  those organisms whose number of individuals in the natural environment is lower than usual and are at risk for extinction. If they fail to reproduce, extinction or the disappearance of these species on Earth might occur.
• Total number of plant species in the Philippines

  14000 to 15310
• Total number of vertibrate species in the Philippines

  3308 to 3325  
• Total number of invertibrate species in the Philippines

  34940 to 35000       
• Other species in the Philippines

  >6100  
• Total number of species present in the Philippines

  53500
• The Philippines has one of the most unique sets of organisms on Earth. It is the home to several endemic species that also experience threats to their existence.
• Philippine eagle, Pithecophaga jefferyi

  
• Philippine tamaraw, Bubalus mindorensis

  
• waling-waling, Vanda sanderiana

  
• Examples of endemic and endangered Philippine species

  • Philippine eagle, Pithecophaga jefferyi;
  • Philippine tamaraw, Bubalus mindorensis;
  • waling-waling, Vanda sanderiana
• Overexploitation of these organisms for food and other economic purposes has caused a decline in their number in their natural environment.
• Examples of Endemic Species in the Philippines

  • Palawan fruit bat
  • Philippine flat-headed frog
  • Philippine dwarf kingfisher
  • Philippine flying lemur
  • Samar squirrel
  • Mindoro black rat
• Palawan fruit bat

  Acerodon leucotis
• Philippine flat-headed frog

  Barbourula busuangensis
• Philippine dwarf kingfisher

  Ceyx melanurus
• Philippine flyinglemur

  Cynocephalus volans
• Samar squirrel

  Sundasciurus samarensis
• Mindoro black rat

  Rattus mindorensis
• In addition, the Philippine islands are surrounded by bodies of water.

  • This led to the isolation of organisms within each island.
  • These organisms changed and became highly different over time compared with those present in other islands.
• The rich biodiversity of the Philippines can be related to the origin of the different islands of the country.

  • During the formation of the Philippines, evolutionary biologists say that some of its islands came from mainland Asia, while its other islands emerged from under the ocean.
  • In terms of biodiversity, this would imply that the plants and animals in the country come from various sources, making them highly diverse.
• It is also implied that some animals or plant ancestors gave rise to several descendant species all within the Philippines.
• Measurements of Biodiversity

  • abundance
  • species richness
  • species density
• Richness

  • refers to the number of different species in a given place
  • If a forest has twelve different species of plants and animals, then the richness of that forest is twelve.
• Abundance

  • is described as the number of individuals of the same species present in a place.
  • This provides an idea of the population size of a species within the area.
  • ${Abundance} =$$\text{total number of individuals per species}$
• Species density

  • is the number of individuals per species relative to the area of a certain place.
  • provides information regarding the distribution of a species per unit area.
  • we can determine if a species tends to clump together in a certain place or if they prefer to be evenly distributed throughout the area.
  • $\text{Species density} =$$\frac{\text{number of individuals per species}}{\text{total unit area}}$
• Aggregation

  • high numbers of one species clump together at one area for a period of time
  • a pattern of distribution that has implications on the density of species.
• Extinction

  • a biological status that a species undergoes when all of its living members have died out
  • can be determined as to the death of the last remaining individual of the species or the incapacity of these members to breed and create offspring to continue their generations
  • one of nature’s natural ways to balance an ecosystem by killing dominant species and making room for the growth of other organisms to rapidly diversify and evolve
• In Earth’s history, several extinction events have happened that led to the disappearance of more than 90 per cent of the original number of species present on Earth.
• Cebu warty pig

  • extinct Philippine species
  • extinct in 2000 due to habitat destruction
• Dodo bird

  • found in Mauritius
  • It went extinct due to overexploitation and hunting.
• Causes of Extinction

  • Environmental Phenomena
  • Competition
  • Predation
  • Diseases
  • Habitat Degradation
  • Climate Change
  • Introduction of Invasive Species
• Environmental Phenomena  

  • volcanic eruptions, asteroid collisions, and rising sea levels are the major phenomena that caused mass extinctions on Earth.
  • possible reason for the eradication of the dinosaurs
• Eradication of the dinosaurs

  • caused by Environmental Phenomena
  • between the Cretaceous and Triassic periods (about 65 million years ago)
  • wiped out all non-avian dinosaurs and paved the way for modern organisms to grow and evolve.
• Brown tree snake (Boiga irregularis)

  
• Competition and Predation

  • existence of highly dominant predators and competition over resources are good driving forces of species to go extinct
  • inability of the prey to adapt and cope with their predators may lead to the drastic depletion of their populations
  • decreases the ability of species to reproduce as the resources and nutrients needed for reproduction are not enough