- Identify the total number of species (4,000) and the total time period (2 years).
- Form the ratio \(\frac{4,000 \text{ species}}{2 \text{ years}}\) to represent the discovery rate.
- Simplify the fraction by dividing both parts by 2 to obtain the unit rate of \(\frac{2,000 \text{ species}}{1 \text{ year}}\).
- The final unit rate is \(\boxed{\frac{2,000 \text{ species}}{1 \text{ year}}}\).
Explanation
- Analyzing the Problem and Data
The problem asks us to determine the unit rate of discovery for new marine animal species. We are given that 4,000 new species were discovered over a period of 2 years. A unit rate is defined as the ratio of two quantities where the denominator is 1, in this case, the number of species discovered per 1 year.
- Calculating the Unit Rate
To find the unit rate, we set up the ratio of the total number of species discovered to the total time period:
\[ \text{Rate} = \frac{4,000 \text{ species}}{2 \text{ years}} \]
To express this as a unit rate, we simplify the fraction such that the denominator becomes 1. We divide both the numerator and the denominator by 2:
\[ \frac{4,000 \div 2}{2 \div 2} = \frac{2,000 \text{ species}}{1 \text{ year}} \]
Thus, the unit rate of discovery is 2,000 species per year.
- Conclusion
Comparing our calculated unit rate of \(\frac{2,000 \text{ species}}{1 \text{ year}}\) to the given options, it is clear that the first option is the correct answer. The final answer is \(\boxed{\frac{2,000 \text{ species}}{1 \text{ year}}}\).
Examples
Unit rates are used in everyday life to compare speeds, prices, or efficiencies. For example, if you are grocery shopping and want to find which brand of juice is cheaper per ounce, you calculate the unit price (price per ounce) for each brand. Similarly, in science, expressing discovery rates as "species per year" helps researchers understand how quickly new knowledge is being gained over time, making it easier to communicate findings and analyze trends effectively.