Extinction

Lesson 2: Extinction Understanding Extinction

• Definition: Extinction is the continuous decrease without compensation in the number of a certain species of living organisms until all members of that species die out.

• Living organisms exist in a state of equilibrium, where the number of one species balances with another.

• Extinction occurs when a species' population decreases continuously without equivalent increases from other populations.

The Fossil Record

• Fossil Record: Contains the sequence of fossils left in sedimentary rocks over millions of years.

• Indicates:

  • Types of living organisms that existed at different times.

  • Examples of extinct organisms from ancient times, e.g., Dinosaurs, Archaeopteryx, and various fish species.

Reasons for Extinction

• Historical Extinctions (Macro Extinctions)

  • Causes attributed to macro extinctions (e.g., Dinosaurs):

    • Meteorite impacts.

    • Violent Earth movements.

    • Prolonged ice ages.

    • Toxic gases from volcanic eruptions.

• Recent Extinctions:

  • Recent extinctions are primarily caused by human interference:

    • Destruction of natural habitats.

    • Overhunting of species.

    • Environmental pollution.

    • Climatic changes caused by human activity and natural disasters.

  • Example: Death of marine birds due to oil pollution arising from industrial activities.

Extinct and Endangered Species

• Extinct Species:

  • Ancient Extinct Species: Significant extinction events included approximately 100 million organisms; notable examples:

    • Dinosaurs: Became extinct millions of years ago.

    • Mammoth: An ancestor of the modern elephant, known for its size and fur.

  • Recent Extinct Species:

    • Dodo Bird: A non-flying bird that fell prey to hunting due to its size.

    • Quagga: A mammal viewed as a bridge between horses and zebras.

• Endangered Species:

  • There are around 5000 endangered species, including:

    • Panda Bear

    • Rhinoceros

    • Ibis Bird

    • Barbary Sheep (Arui)

    • Bald Eagle

    • Papyrus Plant: Used historically to make paper in ancient Egypt.

Effects of Extinction on Ecological Equilibrium

• Food Chain: Energy transfer path from one living organism to another in an ecosystem.

  • Example food chain: Sun ➔ Green Plant ➔ Locust ➔ Frog ➔ Snake ➔ Owl.

• Food Web: A network of interconnected food chains.

• Balance of Ecosystem: Each organism plays a vital role; absence of even one species disrupts energy transfer, affecting the entire ecosystem.

  • Consequences of extinction can create gaps in energy pathways, leading to imbalances.

Ecosystem Classification

• Simple Ecosystem: Few species, highly affected by the loss of any member.

• Complicated Ecosystem: Many species, less impacted by the loss of a single member due to alternative species compensating.

  • Examples:

    • Simple: Desert

    • Complicated: Tropical forest

Conservation of Species

• Strategies to Protect Endangered Species:

  • Implementing regulations on hunting.

  • Raising awareness about the importance of biodiversity for human survival.

  • Breeding endangered species and reintroducing them into their natural habitats.

  • Establishing gene banks for preservation.

  • Creating natural protectorates to provide safe spaces for endangered species to thrive.

• Notable Natural Protectorates:

  • Global Protectorates:

    • Yellowstone Protectorate - USA

    • Panda Protectorate - Northeastern China

  • Egyptian Protectorates:

    • Ras Mohamed Protectorate - First established in 1983 (South Sinai).

    • Wadi El-Hetan Protectorate - Known for well-preserved whale fossils (El-Fayoum).

Summary of Key Points

• Extinction: Continuous decline until no members remain.

• Causes of Extinction: Range from natural catastrophic events to human activities.

• Examples of Extinct Species: Dinosaurs, Mammoths, Dodo, and Quagga.

• Endangered Species: Include the Panda bear, Rhinoceros, and Bald Eagle.

• Ecosystem Impact: Extinction disrupts energy pathways and affects ecological balance.

• Conservation Efforts: Regulations, awareness, breeding programs, and protected areas are crucial.