Mass Extinction (1) PDF

MASS EXTINCTION - Driven by a quadrupling of atmospheric CO2 levels, Uptick in CO2 = acidified oceans, making it more TRUE OR FALSE?...

MASS EXTINCTION - Driven by a quadrupling of atmospheric CO2 levels, Uptick in CO2 = acidified oceans, making it more TRUE OR FALSE? difficult for marine creatures to build their shells o There are a time that humans and dinosaurs existed from calcium carbonate on the Earth at the same time. - brachiopods, gastropods, bivalves, and marine o Plants and animals on Earth have always existed. reptiles become extinct. o The Earth is too big to change. ✓ Cretaceous - Paleogene Extinction What is Earth? - (66 million years ago) - The only definitive extinction connected to a major - AGE: 4.543 billion years asteroid impact. - Has Biotic and Abiotic Factors - Dinosaur extinction. - LIFE ON EARTH: 3.5 billion years EXTINCTION ✓ Holocene Extinction - (11,600 years ago – Present) - Extinction (Barbault, 2013) - Human impact: it is believed to have started when human learn to use up fire up to industrial → disappearance of any lineage of organisms, revolution; from populations to species and higher - Deforestation and desertification, Hunting and taxonomic categories). It can be local overharvesting, Overfishing, Burning of fossil (extirpation) or global (total). fuels, Emission of Greenhouse gases -Background extinction rate (Proença & Pereira, Extinction and its Relation to Diversity According to Fossil 2013) Records (Levinton, 2013) → one species per million species per year, or between 10 and 100 species per year. - Mass extinctions caused world-wide precipitous loss of species, over a wide variety of taxonomic -Mass Extinction (Twitchett, 2013) groups and habitats → rapid loss of a large fraction of biodiversity on - Environmental change in mass extinctions timescales of 100– 106 years, generally overwhelm the ability of a species to survive by involving a variety of unrelated groups. profound changes in the environment over the whole species range. MASS EXTINCTION - The major mass extinctions eliminated a very large majority of the species on the planet and caused ✓ Ordovician-Silurian Extinction (440 million years major reorganization of the world’s biota. ago) - In many cases, extinction appears to be selective - Two main phases: Glaciation Event (changes in regarding ecological characters of the groups that oxygenation of the ocean + reduced ocean level) survive, but in others one cannot identify any traits and Heating Event that make a group more resistant to extinction than - Its major casualties were marine invertebrates others. including brachiopods, trilobites, bivalves and corals; STATISTICS OF SPECIES (WAGLER, 2018) ✓ Late Devonian Extinction (365 million years ago) - Algal Bloom and Global Cooling - 19% of all families and 50% of all genera became extinct (E.g., jawless fish, brachiopods, ammonites, and trilobites). - Permian-Triassic Extinction (252 million year ago) - “Deadliest extinction” / “Great Dying” due to “Toxic Environment”. - Volcanic activity in Siberia released 14.5 trillion tons of carbon - 95 percent of the marine species and 70 percent of SPECIES CATEGORIES(Based on National Geographic, the terrestrial species are lost (Survivors: Ancestors World Wildlife Fund) of mammals and birds (therapsids – mammal-like Eurasian Tree Sparrow reptile), as well as tetrapod like synapsids and Rufous hornbill – VS in 2022 archosaurs) Tarsier – NT in 2019 Javan rhinoceros ✓ Triassic-Jurassic Extinction (201.3 million years ago) - Earth warmed an average of between 5- and 11- degrees Fahrenheit The IUCN Red List of Threatened Species(Proença & Pereira, 2013) Life below Water (BSCP, 2022) - list built by the International Union for - Great Hammerhead shark (Sphyrna mokarran) – Conservation of Nature (IUCN) that provides Endangered information on the global conservation status of - Dugong (Dugong dugon) – Vulnerable assessed species of plants and animals. - Lana’s Sawshark (Pristiophorus lanae) – Not evaluated - Giant Manta Ray (Mobula birostris) – Vulnerable - Irrawadday Dolphin (Orcaella brevirostris) – Endangered - Whale Shark (Rhincodon typus) – Endangered Definitions: - Demographic stochasticity (Hunter and Gibbs, 2006) → uncertainty resulting from random variation in reproductive success and survivorship at the individual level (population’s size, sex, and age structure, and its natality and mortality rates) → Allee effect (Hunter and Gibbs, 2006) - Phenomenon in which some species is not sufficient to have a balanced age and sex structure; Positive Density Dependence - Environmental stochasticity (Hunter and Gibbs, 2006) → refers to random variation in components of habitat quality, such as climate, nutrients, water, cover, pollutants, and relationships with other species that might be prey, predators, competitors, parasites, or pathogens. → Extinction Debt (Kuussaari et al., 2009) - In ecological communities, the number or proportion of extant specialist species of the focal habitat expected to eventually become extinct as the community reaches a new equilibrium after environmental disturbance.  - Ecological overlap (E.g., A flock of black-faced spoonbills (Platalea minor) were seen flying northwards in Barangay Taliptip, Bulakan, Bulacan) - Large homerange requirements (E.g., Pithecophaga jefferyi) Note: 40% of world’s plant speciesat risk of extinction(Antonelli et al., 2020) ECOLOGICAL BACKSLASH - when a consequence occurs unexpectedly after an environment has been altered in some way. (E.g., oil spills, flash floods, and pest control) Biodiversity PH 101 (BSCP, 2022)Ph “Super Endemics” - Endemics; Livings things which can be found only in the Ph (more than 10,000). - Super endemics; super unique endemics only found in a specific/one place - Calayan rail (Gallirallus calayanensis) ; Found only in one island (Calayan) - Tawilis (Sardinella tawilis) ; Found in only in one lake (Taal Lake) Note: Rare species are usually more vulnerable to extinction, - Banahao shrew rat (Rhynchomys banahao) ; Found but population size and distribution are not the only in only one mountain (Mt. Banahaw) predictors (Hunter & Gibbs, 2006) Critically Endangered Flora and Fauna in the Philippines - Conservation International, a nonprofit environmentalist group founded in 1987, recognizes the Philippines as one of only 17 mega- diverse countries in the world. - Mega-diverse countries are nations that shelter the bulk of Earth's animal and plant life; With so much biological diversity, the country is also home to a large number of threatened animal species. - The International Union for the Conservation of Nature and Natural Resources (IUCN), has declared 418 animal species in the Philippines to be threatened: meaning they are either vulnerable, endangered, or critically endangered, according to the IUCN red list criteria. Philippine Eagle (Pithecophaga jefferyi ) Critically endangered by the IUCN - Also called the monkey-eating eagle - the Philippine eagle is native to the southern Philippines. Why Are Some Species Particularly Sensitive to Human- - It is characterized by a brown and white feather induced Threats? (Hunter & Gibbs, 2006) pattern and bushy crest and is believed to be one of the largest and most powerful birds on Earth. - Limited adaptability & resilience (E.g., Drosophila - A full-grown adult can grow to as big as four feet melanogaster and Loxodonta Africana) (ft) tall and can weigh as much as nine kilograms - Human attention (E.g., Ailuropoda melanoleuca (kg). and Drymarchon couperi)  - The monkey-eating eagle is the Philippines national Attenborough’s Pitcher Plant(Nepenthes attenboroughii ) bird. Major threats to the Philippine eagle's survival are deforestation, mining, and pollution. - It is named after the celebrated broadcaster and naturalist Sir David Attenborough, who is a keen enthusiast of the genus Philippine Freshwater Crocodile (Crocodylus mindorensis ) - Able to capture and digestrodents and other small Critically Endangered by the IUCN animals. - Overcollection and poaching for the rare plant - Locally known as Mindoro crocodiles, trade; habitat destruction due to agriculture and - The Philippine freshwater crocodile is quite small human development; and drought caused by climate compared to other crocodiles, growing to about four change. and a half to five feet long and weighing approximately 15 kg. Visayan Warty Pig (Sus cebifrons ) Critically Endangered by - It is reported that as of September 2011, there are the IUCN only 250 of them left in the country; Experts attribute illegal hunting and dynamite fishing to the - This land mammal is once ubiquitous in the central decline of the Philippine freshwater crocodile. Philippines, especially in the island of Cebu, the pig can now only be found on two islands: Panay and Did you know? Negro; Some experts believe that a small herd may still be in the island of Masbate although it is not ✓ Philippine has two species of crocodiles – Ph. confirmed. Crocodile (Crocodylus mindorensis, Endemic and - The disappearance of this species on the island of critically endangered) and Saltwater crocodile Cebu was not only brought about by illegal hunting (Crocodylus porosus, Native and Least concern). and logging but also agricultural land clearing. Once found all over the Philippines, their - Now, small population concentrations of this population and distribution has dwindled because of species are bred in captivity; Some still live in the habitat loss and persecution. wild, although they are very rare, which is why not Philippine Teak(Tectona philippinensis) much is understood about the mammal's natural behavior. - The species is endangered due to land conversion and logging for its timber. - can be found only in Luzon and Ilin, a small island south of Mindoro (Merrill 1923, Madulid and Agoo 1990, Rojo 1999, Caringal 2004, Caringal 2012). Tamaraw (Bubalus mindorensis ) Critically Endangered by the IUCN - Also known as the Mindoro dwarf buffalo - the only known bovine (cow) that is indigenous to the Philippines. - Until the 20th century, the original habitat of this species was essentially intact and unharmed; They were once found all over Mindoro Island, from the plains up to the mountains. - But now the population has been reduced to about 200, with many being carefully bred in captivity. - Illegal hunting, logging, and residential land clearing. Walden's Hornbill (Aceros waldeni )Critically Endangered by the IUCN - Locally called a Kalaw or the Visayan Wrinkled Hornbill - Endemic to the Philippine islands of Panay and Negros, although it can also be found in other regions of the country such as Zamboanga del Norte in Mindanao. - Excessive hunting and illegal logging caused the disappearance of this species in the areas of Negros and Guimaras.