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How Animal Populations Interact
How Animal Populations Interact

The Difference Between Prokaryotes and Eukaryotes
All living organisms can be sorted into one of two groups depending on the fundamental structure of their cells. These two groups are the prokaryotes and the eukaryotes.

The Anatomy of a Cell
The cell is a fundamental component of our modern definition of life and living things. The cell is regarded as the basic building block of life and is used in the elusive definition of what it means to be 'alive'.

A Guide to Vertebrates and Invertebrates
Among the most basic criteria by which animals are sorted is whether or not they possess a backbone. This single trait places an animal into one of just two groups: the vertebrates or the invertebrates.

A Beginner's Guide to Amino Acids and Proteins
Proteins are organic molecules that are vital to the structure and function of living organisms. The underlying elements that make up all proteins include carbon, hydrogen, oxygen, nitrogen and (in some cases) sulfur.

A Beginner's Guide to Nucleic Acids
Nucleic acids provide organisms with a means for storing and transmitting genetic information. These linear, unbranched biopolymers are made up of nucleotide subunits (or monomers). Nucleic acids include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).

A Visual Guide to Purines and Pyrimidines
Nucleic acids such as DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) provide organisms with a means for storing and transmitting genetic information. These linear, unbranched biopolymers are made up of building blocks called nucleotides.

An Introduction to Zoology
Zoology is the study of animals (Gr. zoon, animal + logos, to study). This sounds like a simple definition, but upon further clarification, the "study of animals" turns out to be a broad and complex subject matter. The "study of animals" calls upon many other scientific disciplines.

Animal Cells, Tissues, Organs and Organ Systems
The buildling blocks of matter (elements and molecules) form the basis for increasingly complex substances that make up living organisms. Simple molecules combine to form more complex macromolecules which in turn are the building blocks for the membranes and organelles that make up living cells.

Animals and Their Environment
A first step to understanding individual animals, and in turn populations of animals, is to understand the relationship they have with their environment. The environment in which an animal lives is referred to as its habitat.

Communities and Ecosystems
Going beyond populations of animals, we find that larger-scale structure can be seen. The understanding of these higher-level components, which include communities and ecosystems, is inseperable from our understanding of the animals that live in them.

Comparing Prokaryote and Eukaryote Cells
All living organisms can be sorted into one of two groups depending on the fundamental structure of their cells. These two groups are the prokaryotes and the eukaryotes.

How Animal Populations Interact
Populations of animals interact with each other and their environment in a variety of ways. One of the primary interactions a population has with its environment and other populations is due to feeding behavior.

How Animals Move Underwater
The underwater world holds many challenges. The most basic of these is movement. The density of water makes it difficult for animals to move.

Population Growth and Regulation
Populations are groups of individuals belonging to the same species that live in the same region at the same time. Populations, like individual organisms, have unique attributes.

The Chemistry of Animal Life
Animals, like all lifeforms, are composed of and dependent upon the chemicals of life. To understand the chemistry of life, we need to first understand the basics of general chemistry.

Understanding Animal Organ Systems
Animals' bodies are made up of various organ systems, groups of organs that work together to perform a function. In this article you can find out more about the different organ systems animals can have.

What is a Vestige?
When used with respect to animals (and other organisms), the term vestige refers to an under-developed and often no-longer-used body part that was present in fully developed and functional form in past generations.

What is Counter Shading?
Counter shading is a common color pattern in animals in which the dorsal side (upper side) of the animal is darker than the ventral (lower) side. Such a color pattern provides camouflage for the animal when viewed from above, below, and even from the side.

What is Sexual Dimorphism?
Sexual dimorphism is the difference in form between male and female members of the same species.

What Makes an Organism an Animal?
What is an animal? It's a simple enough question, but the answer is complex and requires an understanding of some rather hefty scientific concepts and terms. Here we'll explore the basic characteristics that makes an organism an animal and attempt to decipher the scientific jargon that surrounds these concepts.

Quiz: An Introduction to Zoology
This quiz is based on the content covered in the Zoology 101 online course.