How many species are threatened with extinction?

Grade level: 5th grades

Skills: Place Value 

Related environmental issues: Biodiversity

At the present time, there are 28,338 kinds of plants and animals (species) that are at risk of becoming scarce within the foreseeable future in the world. They are threatened with extinction mainly because they lost their homes. Humans are responsible for the habitat loss when they destroy their habitats by developing housing, highways, industry, and agriculture.

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1. what is the value of the underlined digit in 28,338?

2. What digit is in the tens place in 28,338?

3. What place is the 2 in 28,338?

4. What is the relationship between the values of the underlined digits?

  • 28,338 and 28,338
  • 28,338 and 28,338

Sources: IUCN Red List of Threatened Species (Table 1-b), 2019

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Answer keys

1. 8,000

2. 3

3. ten thousands

4. When comparing the underlined digits, the first 8 represents 8 thousands, whereas the latter 8 represents 8 ones

When comparing the underlined digits, the first 3 represents 3 hundreds, whereas the latter 3 represents 3 tens

How many non-native marine species were found in Galápagos islands?

Grade level: 6th grades

Skills: Percentage and addition

sRelated environmental issues: Biodiversity

The Galápagos islands, which lie in the equatorial Pacific, have long been recognized for their remarkable biodiversity and their large number of endemic species.  However,  the environment of the Galápagos islands started to change because many non-native species have been brought to the islands by human activity over the last 500 years.

galapagos-islands1.jpg

A recent research identified 53 non-native marine species in the islands.

  1. The research showed that 93% of the 53 species were likely brought to the Galápagos Islands by ships. How many non-native marine species were brought by ships? Round to the nearest whole number.
  1. The Galápagos islands were first visited by Europeans in the 1500s. By the late 1960s, 2000–3000 people lived on the Islands. In a 2010, there were 25,000 residents and one-quarter million visitors annually. Together, how many residents and tourists a year are there in the Galápagos islands?

 

Answer keys

  1. 49 species (53 x 0.93 = 49.29)
  2. 275,000 (25,000 + 250,000= 275,000)