Extinction and Endangered Species PDF

# Lesson 2: Extinction ## Why are some animals species no longer exist on the planet Earth? From your previous studies, you know that living organisms are always in a state of equilibrium. The number of a certain kind of organism does not exceed the number of another species. The continuous decrea...

# Lesson 2: Extinction ## Why are some animals species no longer exist on the planet Earth? From your previous studies, you know that living organisms are always in a state of equilibrium. The number of a certain kind of organism does not exceed the number of another species. The continuous decrease in the number of other species without compensation of this decrease in number causes the death of all individuals of this species, which is known as extinction. ## Extinction: * It is the continuous decrease without compensation in the number of a certain species of living organisms until all members of the species die out.  * It is dying out of all members of species of living organisms. ## Using fossil record to indicate extinction: Fossil record includes the sequence of living organisms' fossils which are left in the sedimentary rocks from millions of years ago. ### **Fossil record indicates:** 1. The types of living organisms which lived on Earth in different ages. 2. The types of extinct living organisms which lived on Earth in old ages like: * Dinosaurs * Archaeopteryx * Many types of fish ## Reasons of extinction: ### **A. Reasons of extinction in old ages (macro extinctions)** Many scientists attributed macro extinctions of some living organisms (like extinction of dinosaurs) due to the occurrence of: 1. Meteorite impacts with Earth. 2. The violent Earth movements. 3. Exposure of the Earth to a long ice age. 4. Toxic (poisonous) gases which evolved from volcanoes. ### **B. Reasons of extinction in recent ages** Recent extinction occurred now is caused by different factors. Most of them are due to the interference of man with nature such as: **1. Destroying natural habitat:** * Cutting trees of forests **2. Overhunting** **3. Environmental pollution:** * Death of marine birds due to oil pollution **4. Climatic changes resulted from industrial activities of man and natural disasters:** * Drought # Unit 3: The extinct and endangered species ## First: The extinct species ### **Examples of some extinct species in the old times:** Hundred millions of organisms became extinct in the old times. The most famous of them are: 1. **Dinosaur** * Dinosaur became extinct from millions of years ago. 2. **Mammoth** * Mammoth is called the grandfather of the recent elephant. ### **Examples of some extinct species in the recent times:** 1. **Dodo bird:** * It is a non-flying bird. * Due to the reduced size of its wings, it is an easy target for hunters. 2. **Quagga** * It is a mammal animal. * It is considered the midway between horse and zebra. ## Second: The endangered species ### **Examples of some endangered species:** There are about 5000 endangered species like: 1. **Panda bear** 2. **Rhinoceros** 3. **Ibis bird** 4. **Barbary sheep (Arui)** 5. **Bald eagle** * It is called bald because its head is covered with white feathers, which makes it look like bald. 6. **Papyrus plant** * It is used by Pharaohs to manufacture writing papers. ## Note: Ibis bird, barbary sheep and papyrus plant are considered from Egyptian environmental organisms. ## Effect of extinction on the ecological equilibrium ### **Food chain:** At any ecosystem, the energy transfers through a path which is known as the food chain. It is a path of energy that transfers from a living organism to another in the ecosystem. Each living organism has a role in transferring energy throughout the food chain, as energy transfers from producers to consumers. * **As in the following chain:** - Sun - Green plant (producer) - Locust (1st consumer) - Frog (2nd consumer) - snake (3rd consumer) - Owl (4th consumer) ### **Food web:** Groups of food chains are connected forming food web. It is a group of food chains connected with each other. * **The system remains balanced unless one of its members is absent.** * **When an organism disappears, its role stops, affecting the rest of members of the food chain or the food web.** ## Exercise: The following figure shows a terrestrial food chain: 1. Green plant - Locust - Frog - Snake - Owl ## What happens in the absence of frogs? - Snakes die due to starvation and the number of locusts will increase and destroy the green plants. ## What happens in the absence of snakes? - Owls die due to starvation, so the number of frogs will increase and pounce on the locusts. - “In the two cases, there is a disturbance in the ecosystem.” ## **What are the consequences of… extinction of species or a group of species from a balanced ecosystem?** It causes a cavity (cut link) in the path of energy in this ecosystem that would disturb the ecosystem equilibrium or destroy it. ## Ecosystem is classified according to the degree of the effect of extinction on it into: ### 1. **Simple ecosystem:** * It is an ecosystem that has a few members and it is strongly affected by the absence of one of its species. ### 2. **Complicated ecosystem** * It is an ecosystem that has multiple members and it is not affected much by the absence of one of its species. ### **Characteristics:** | Simple Ecosystem | Complicated Ecosystem | |------------------------------------|--------------------------------| | It is characterized by containing a few number of members of living organisms (few members). | It is characterized by containing a large number of members of living organisms (multiple members). | | It is strongly affected by the absence of one of its species. Because of the rarity of alternatives that compensates this absence. | It is not affected much by the absence of one of its species. Because it has many alternatives. | ### **Examples** | Simple Ecosystem | Complicated Ecosystem | |-------------------|-----------------------| | Desert | Tropical forest | ## Ways to protect living organisms from extinction It was necessary for the scientists to think in ways of protection of species endangered by extinction to keep the ecological balance and so the ecological systems from destruction. ### **Ways to protect rare and endangered living organisms:** 1. **Putting laws which regulate the process of hunting of living organisms especially the rare types.** 2. **Increasing awareness about the importance of natural life to sustain the existence of mankind.** 3. **Breeding and reproducing the endangered species and sending them back to their native habitats.** 4. **Establishing gene banks for the endangered species.** 5. **Establishing natural protectorates areas.** ## Natural protectorates * They are safe areas established to protect endangered species in their homeland. ### **Importance of natural protectorates:** Natural protectorates provide the endangered species with suitable conditions for growth and reproduction away from their natural enemies. ## The important world’s protectorates: | Protectorate | Location | Protected Kinds | |--------------------|-----------------|-----------------| | Yellowstone protectorate | USA | Grey hear | | Panda protectorate | Northeastern China | Panda bear | ## Egypt's important protectorates: | Protectorate | Location | Protected Kinds | |---------------------------------------|-------------------------------------------------------------------|-------------------------------------------------------------| | 1. Ras Mohamed protectorate: | South Sinai governorate. | Rare species of coral reefs and colored fish. | | 2. Wadi El-Hetan (part of Wadi El-Raiyan protectorate). | El-Fayoum governorate. | Complete whales' skeleton fossils (40 million years ago). | | 3. Wadi El-Hetan (part of Wadi El-Raiyan protectorate in El-Fayoum) | | **G.R.** | ***G.R. Wadi El-Hetan (part of Wadi El-Raiyan protectorate in El-Fayoum) is considered the most important area in this protectorate. Because it contains complete whales' skeleton fossils 40 million years ago.*** **Note:** Ras Mohamed protectorate (shaped as a chin). ## Enrichment information: Number of natural protectorates that had been established according to the law (number 102 year 1983) is about 30 natural protectorates till 2012 which are found on about 15% of the total area of Egypt. ## Remember ### Extinction: * It is the continuous decrease without compensation in the number of a certain species of living organisms until all members of species die out. * It is dying out of all members of species of living organisms. ### Among factors causing old (or macro) extinctions are: 1. Meteorite impacts with Earth. 2. The violent Earth movements. 3. Exposure of the Earth to a long ice age. 4. Toxic (poisonous) gases which evolved from volcanoes. ### Among factors causing recent extinction are: 1. Destroying natural habitat. 2. Overhunting. 3. Environmental pollution. 4. Climatic changes and natural disasters. ### Among examples of some extinct species in the **old times** are: Dinosaurs and Mammoths. ### Among examples of some extinct species in **the recent times** are: Dodo bird and Quagga. ### Among examples of some endangered species are: Panda bear - Rhinoceros - Bald eagle - Ibis bird - Papyrus plant and Barbary sheep. ### **Food chain:** It is a path of energy that transfers from a living organism to another in the ecosystem. ### **Food web:** It is a group of food chains connected with each other. ### **Ecosystem is classified according to the degree of the effect of extinction on it into:** 1. Simple ecosystem. 2. Complicated ecosystem. ### **Natural protectorates:** They are safe areas established to protect the endangered species in their homeland. ### **Ex:** Yellowstone protectorate, Panda protectorate, Ras Mohamed protectorate and Wadi El-Hetan protectorate.