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ECO Alphabet: Week 5: Endangered Species

Updated: Sep 17, 2020

An estimated 50% of the world's species are at risk for extinction..

endangered species, Hawaiian monk seal, conservation, sustainability, eco friendly
Hawaiian Monk Seal

We are in the midst of our 6th mass extinction! This is the worst event of species dying off since the dinosaurs 65 million years ago!

Extinction is a natural phenomenon usually occurring at about 5 species/year.

We are at about 1,000 times that rate at 12 species/day...

Below I will tell you what an endangered species is, how we are affecting the rate of endangerment, and what we can do about it! Enjoy!

What is an endangered specie?

An endangered specie is a species threatened to extinction. Pretty straight forward, right?

Levels of Endangerment:

  • Vulnerable: if population declines 30-50% or if there are fewer than 10,000 mature individuals. This is measured over 10 years or 3 generations (whichever is longer). Example - Ethiopian Banana Frog and Snaggletooth Shark

  • Endangered: if population declines 50-70% or if there are fewer than 2,500 mature individuals. This is measured over 10 years or 3 generations (whichever is longer). Example - Ebony trees and Tahiti Red-warbler

  • Critically Endangered: if population declines 80-90% or if there are fewer than 250 mature individuals. This is measured over 10 years or 3 generations (whichever is longer). Example - Bolivian Chinchilla Rat and Transcaucasian Racerunner

Why are species becoming endangered in the first place?

Top 10 reasons for endangerment:

  • Overhunting/harvesting

  • Habitat Loss

  • High Specialization

  • Pollution

  • Invasive Species

  • Human-wildlife Conflict

  • Disease

  • Genetic Vulnerability

  • Small Population

Of these top 10, five are due to human effect... (those in bold)


This is just as it sounds. If we over hunt or harvest we will diminish the population without giving it a chance to reproduce.

Habitat Loss

Some habitat loss is natural like when the dinosaurs went extinct; however, a large amount is is human caused by housing, industry, and agriculture.

To "clear" land is to remove all trees and vegetation from piece of land.

If a tree is destroyed (like in the Amazon Rainforest) other species that live in said tree are at risk of endangerment.


A specific example of how pollution is effecting species is the Declining Amphibian Phenomenon. Amphibians are at the highest rate of endangerment due to their sensitivity to the environment.

Invasive Species

When a new specie enters the environment it has no natural predators. Therefore it begins to annihilate it's new environment. Some examples are Lionfish and Kudzu.

Lionfish were released to the American east coast when people no longer want them as aquarium pets. They are originally from the Japanese coast. They now prey on several animals and have no predators to prey on it. Therefore they have become almost like an indestructible species that is rapidly growing.

Human-Wildlife Conflict

When people move where wildlife live in abundance, they usually end up killing said wildlife out of fear of danger.

99% of threatened species are at risk from human activities.

Because of the linkage of species via the food chain/web there is a snowball effect...

What can we do about it?

  1. Education

  2. Make your home wildlife friendly: secure garbage cans, reduce use of water, disinfect birdbaths

  3. Plant a butterfly garden: this will lead butterflies to pollinate plants

  4. Avoid herbicides and pesticides

  5. Don't purchase products made of endangered species: tortoise shell ,ivory, coral

  6. Don't harass wildlife

  7. Clean up local areas when you see trash

  8. SPREAD THE WORD: word of mouth is the most effective way to create action!



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