Unit B

Module 3 ~ Lesson 2

Climate and Biomes

Abiotic factors determine where life exists and how it is distributed. Biotic components determine how an organism interacts with other organisms to ensure their survival. Abiotic factors cause weather conditions that are referred to as climate. The unequal heating of the Earth's atmosphere causes major climate zones and produces air and water currents that interact with physical features (mountains, islands, and lakes) to produce rainfall patterns. All of these and other factors create large areas with similar environmental conditions called biomes.

At higher elevations on Mt. Athabasca in Jasper National Park, the temperature drops. This is the taiga biome, a cold mountain forest. The change in biomes as you increase in altitude is similar to the change in biomes that occurs as you increase in latitude toward the North Pole. This phenomenon is shown in the following diagram.

Image by Free-Photos from Pixabay


Concordant Biogeographic Patterns among Multiple Taxonomic Groups in the Mexican Freshwater Biota - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Relationship-between-species-richness-and-latitude-for-all-samples_fig12_264902670 [accessed 10 Apr, 2020]

There are fewer living things closer to the mountain summit. Fewer organisms are able to survive at a high altitude and low temperatures. The same decrease in the numbers of species occurs from the equator to the North Pole. This is due to the decrease in average temperature and the decrease in the average precipitation that occurs closer to Earth's poles. The following graph shows that close to the equator in Central America, there are more species of mammals. The increase in temperature and precipitation in this location allows a more diverse set of organisms to flourish.


Read "Studying Organisms in Ecosystems" and "Climate and Biomes" on pages 93 to 95 of your textbook.


The higher the temperature and the greater the amount of precipitation, the greater abundance of terrestrial life. Very high temperatures can inhibit growth.
The Earth is spherical. Therefore, sunlight strikes Earth unevenly. The equator receives the most direct and intense light. As you move toward the poles, sunlight is spread over larger areas and is more diffuse.
Topography, altitude, latitude, and temperature determine the types and abundance of photosynthetic organisms that can survive in a biome.