Regina's Biology Blog

Woodcock U.S. Fish and Wildlife Service

Look carefully at the picture. Can you see the bird hidden in the shrubbery? All animals must eat to survive. With predators always on the lookout for a meal, prey must constantly avoid being eaten.

The predator-prey relationship is important in maintaining balance among different animal species. Adaptations that are beneficial to prey, such as chemical and physical defenses, ensure that the species will survive. At the same time, predators must undergo certain adaptive changes to make finding and capturing prey less difficult. In the Predator or Prey Game you must choose the correct predator-prey relationship.

More games and quizzes:

• Biology Games and Quizzes

Cell Undergoing Apoptosis © 2001 by the University of Central Arkansas

Cancer is linked to a cell's inability to destroy itself through a process known as apoptosis. Cells that become damaged or infected must be removed to avoid passing on abnormalities. Researchers from the University of Utah have discovered one way in which cells avoid apoptosis. It involves a chromosomal abnormality that is marked by the absence of a telomere. Telomeres are protective caps that are located on the ends of chromosomes.

The study shows that some fruit fly cells with a missing telomere are able to avoid apoptosis and continue to divide. These cells contain a mutated gene and mutated proteins that no longer function properly and are unable to trigger self-destruction. It is believed that the mutated cells avoid apoptosis by somehow adding new telomeres. This enables them to divide and pass along abnormalities which lead to cancer.

Learn more about this discovery, see:

• When Cells Go Bad: Cells That Avoid Suicide May Become Cancerous (Science Daily)

The limbic system is a set of brain structures located at the top of the brainstem and buried under the cortex. The limbic system is responsible for controlling various functions in the body.

Limbic system structures are involved in many of our emotions and motivations, particularly those that are related to survival. Certain structures of the limbic system are involved in memory as well. Two large limbic system structures, the amygdala and hippocampus play important roles in memory.

Structures of the limbic system include the following:

• Amygdala
  
• Hippocampus
  
• Hypothalamus
  
• Olfactory Cortex
  
• Thalamus
  

Learn more about the brain and the limbic system:

• Anatomy of the Brain
  
• Human Brain Quiz

Credit: Gary M. Stolz, USFWS

Savannas are areas of open grassland with very few trees. There are two types of savannas, tropical and semi-tropical savannas. Savannas are typically dry, receiving less than 30 inches of rain on average per year. The lack of water makes savannas a difficult place for tall plants such as trees to grow.

Many of the animals that live in savannas rely on speed for survival, as the vast open areas provide little means of escape from quick predators.

Camouflage is also very important to animals of the savanna. Both predators and prey use this technique to conceal themselves from one another.

Some locations of savannas include Africa, Central America, South America, and Southern Asia.

Learn more about savannas and other biomes, see:

• Land Biomes

Image courtesy of MedValet

Valves are flap-like structures that allow blood to flow in one direction. The heart has two kinds of valves, atrioventricular and semilunar valves.

The atrioventricular valves are thin structures that are composed of endocardium and connective tissue. They are located between the atria and the ventricles.

The semilunar valves are flaps of endocardium that are shaped like a half moon. They are located between the aorta and the left ventricle and between the pulmonary artery and the right ventricle.

Learn more about the heart, see:

• Anatomy of the Heart
  
• Cardiovascular System Quiz
  

With gas prices on the rise, many people are feeling the pain at the pump. With that in mind, researchers have announced that they have discovered a method for converting sugar and other carbohydrates into fuel. They have been able to produce gasoline, diesel, and jet fuel from the process.

The process used to create the biofuel is called aqueous phase reforming. It involves combining a watery solution of sugar and carbohydrates with a series of catalysts to produce certain molecules that split and recombine to form chemicals used to produce petroleum.

Learn more about this discovery, see:

• From Sugar to Gasoline (National Science Foundation)

Hakalau Forest National Wildlife Refuge/USFWS

Tropical rain forests are characterized by dense vegetation, seasonally warm temperatures, and abundant rainfall. They are home to the majority of plant and animal species in the world.

Some locations of tropical rain forests include:

Africa
Central America
Hawaii
West India
Southeast Asia

A great variety of plants can be found in tropical rain forests. Enormous trees as tall as 150 feet form an umbrella canopy over the forest that blocks out the sunlight for plants in the lower canopy and forest floor.

To learn more about rain forests and other biomes, see Land Biomes and Land Biomes Quiz.

Connective Tissue © Richard Harris / BIODIDAC

Connective tissue serves a "connecting" function in the body. It supports and binds other tissues. Connective tissue typically has cells scattered throughout an extracellular matrix.

In vertebrates, the most common type of connective tissue is loose connective tissue. It holds organs in place and attaches epithelial tissue to other underlying tissues.

Another type of connective tissue is fibrous connective tissue. This tissue is found in tendons and ligaments. Some examples of connective tissues include adipose, cartilage, bone, and blood.

Constructing DNA models is a great way to learn about DNA structure, function, and DNA replication.

DNA contains the genetic information for the reproduction of life. Its shape has most often been compared to a twisted ladder.

So how do you make DNA models? The DNA Models page contains examples, computer representations, and how-tos for constructing DNA models.

Learn more about DNA:

• Nucleic Acids
  
• DNA Transcription

Wolf Spider

Sexual cannibalism is a phenomenon that is seen widely among several species of spiders. What is sexual cannibalism? It is an act of cannibalism that occurs when a female of a particular species eats a male of the same species either before, during, or after mating. Why do female spiders exhibit this type of behavior? The answer appears to be a simple one.

Researchers from Miami University in Ohio have discovered that the size of the male spider in relation to the female determines if the male is more likely to be eaten by the female. Studies have shown that in one species of wolf spider, Hogna helluo, small males have an 80 percent chance of being eaten by the female while attempting to mate. Large males, on the other hand, have no risk of being eaten.

What drives the female spiders to consume their male partners? The answer appears to be hunger. The much larger female spider is not likely to turn down an easy meal when presented with an opportunity.

Learn more about this study, see:

• Female Spiders Eat Small Males When They Mate (Science Daily)