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IUCN Red List Update: Reptiles and Cacti Closer to Extinction
Context: The IUCN has warned about the threats posed by invasive species and illegal trade to reptiles and cacti.
IUCN Concern:
- Ibiza wall lizard (Podarcis pityusensis) endangered, 50% decline since 2010 due to invasive horseshoe whip snake (Hemorrhois hippocrepis).
- Gran Canaria giant lizards (Gallotia stehlini) and skink (Chalcides sexlineatus) face extinction due to invasive California kingsnake (Lampropeltis californiae), introduced in 1998.
- Both Gran Canaria species reclassified from least concern to endangered.
- Cacti and succulents around the world are currently in exceptionally high demand as ornamental species.
- Copiapoa cacti in Chile’s Atacama desert, critically endangered (82%, up from 55% in 2013) due to illegal trade fueled by high demand in Europe and Asia via social media.
- Infrastructure development and climate change disrupt hydration patterns, threatening slow-growing cacti survival and reproduction.
Overview of Reptilia:
- Classification:
- Kingdom Animalia
- Phylum Chordata
- Class Reptilia
- Reptilia is a class of cold-blooded vertebrates including snakes, lizards, turtles, and crocodiles.
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- They are characterised by scales, lungs, and laying shelled eggs.
- Reptiles inhabit diverse environments, from deserts to rainforests.
- Many are predators, using adaptations like venom or powerful jaws for hunting.
- Characteristics of Reptilia
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- Heart: Most have a three-chambered heart; crocodiles have a four-chambered heart.
- Reproduction: Reptiles are mostly oviparous, laying macrolecithal eggs; some are ovoviviparous or viviparous, with the development of embryonic membranes (chorion, amnion, allantois, yolk sac).
- Nervous System: They have 12 pairs of cranial nerves.
- Fertilisation: Internal fertilisation.
- Ears: No external ear openings.
- Excretion: Uricotelic, excreting nitrogenous waste as uric acid.
- Skin: Scaled body, some shed scales; scales contain Beta keratin.
- Thermoregulation: Ectothermic, absorbing heat from the environment.
- Habitats: Terrestrial, often burrowing.
- Respiration: Lungs are used for respiration.
- Geographical Distribution: Mostly found in warmer regions.
- Body Structure: Dry, rough skin without glands; body divided into head, neck, trunk, and tail.
- Examples: Turtles, lizards, snakes, and crocodiles.
- Limbs: Tetrapods.
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- Examples of Reptilia: Snakes, Lizards, Turtles, Crocodiles, Alligators, Chameleons, Komodo dragons, Geckos, Iguanas, Tuatara
- Classification of Class Reptilia
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- Anapsida: Solid skull roof, no temporal fossae. Examples: Turtles, tortoises.
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- Parapsida: One temporal fossa high on the skull. Examples: Placodonts, Nothosaurs, Protosaurs, Ichthyosaurs, Plesiosaurs.
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- Diapsida: Two temporal vacuities in the skull. Examples: Chameleons, Crocodilus.
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- Groups: Lepidosauria (e.g., lizards, snakes), Archosauria (e.g., dinosaurs, crocodiles).
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- Importance of Reptilia:
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- Pest control by consuming insects and rodents.
- Biological research, including snake venom for pain management drugs.
- Reptile skin used in the leather industry.
- Alligators and crocodiles prevent fish overpopulation.
- Maintaining ecological balance and biodiversity.
- Some reptiles act as keystone species.
Overview of Cactus?
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- A cactus (plural: cacti, cactuses, or cactus) is a member of the flowering plant family Cactaceae. Native to North and South America,
- Cacti are known for their reduced or ephemeral leaves, enlarged stems, and spines growing from areoles—a structure unique to cacti.
- Adaptations to Dry Environments.
- Water Storage: Succulent stems and roots store water.
- Reduced Leaves: Minimise water loss.
- Spines: Shade the plant, reduce transpiration, and protect against herbivores.
- Areoles: Specialised structures from which spines and flowers grow.
- Photosynthesis: Carried out by the stems.
- Root System: Shallow, wide-spreading roots for water absorption.
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- Taproots for anchoring and accessing deeper water.
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- Crassulacean Acid Metabolism (CAM):
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- Transpiration occurs at night to minimise water loss.
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- Human Uses & Conservation :
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- Food and Medicine, Ornamental Plants.
- Conservation Issues: Some species are endangered due to human activities, while others have become invasive when introduced to non-native areas.
