The Tree of Life: Part 3

The tree of life, as scientists understand it, is not static – it changes. Classification systems have changed with science’s understandings of the diversity and organization of the living world, so don’t think that we know it all! Prior to the 1970s, scientists generally classified living things as Bacteria or Eucarya. The scientific community was […]

Bacteria

Bacteria are everywhere. Only a few micrometers in length and having a wide range of shapes, from spheres to rods to spiral, bacteria are the huddled masses of the microbial world, performing tasks that include everything from causing disease to fixing nitrogen in the soil. Humans need bacteria. In fact, there are approximately ten times […]

The Tree of Life: Part 2

Most of the organisms that scientists know exist fit in the second domain: Bacteria. The bacteria are a large group of unicellular microorganisms. Bacteria are ubiquitous in every habitat on Earth, growing in soil, acidic hot springs, radioactive waste, water, and deep in the Earth’s crust, as well as in organic matter and the live […]

Eucarya

A eukaryote is an organism whose cells are organized into complex structures enclosed within membranes. Many living organisms we are familiar with, including all animals, plants, and fungi, are eukaryotes. The defining membrane-bound structure that differentiates eukaryotic cells from other types of cells is the nucleus. Cells without a nucleus are called prokaryotic cells, and […]

The Tree of Life

The phylogenetic tree or evolutionary tree shows the evolutionary relationships among various biological species. In a phylogenetic tree, each node with descendants represents the most recent common ancestor of the descendants. Each node is called a taxonomic unit. Key Concept: All cells come from preexisting cells. Most broadly, scientists classify life into three domains. Humans, […]

Understanding Soils

When taking soil profiles, scientists tend to focus on specific characteristics and concepts that can potentially tell us the most about the conditions of the soil. They look for microbes to determine what sorts of life are present in the soil, and, by inventorying the microbes in a given soil, scientists can judge the biodiversity […]

Soil Profiles

In order to explore what is living in the soil, we will collect and analyze soil profiles from our field sites, describing physical characteristics of the soil and the microbial and insect communities living there. We will then compare our results with other soil profiles compiled from online sources. We will also compare our results […]

What Is Living in the Soil?

Every day, we step over a world of life hidden in the soil beneath us. In this module, we will investigate the question “What living components can we find in our schoolyard soil?” Before we begin, it may be useful to review the basic definition of soil. You might wonder what exactly soil and dirt […]

Module 3:
Soils

After completing this module, you will be able to: Collect soil samples from your study site using a sound scientific collection method; Culture soil biota using Petri dish and culture media (plating followed by incubation); Describe the living (biotic) and non-living (abiotic) features of your study site; Begin to describe the process for classification of […]