Holt Science & Technology: Life Science (2007)

Cell Structure

Select a sample cell from an animal, plant, or bacterium and view the cell under a microscope. Select each organelle on the image to learn more about its structure and function. Closeup views and animations of certain organelles is provided. 5 Minute Preview

Cell Division

Begin with a single cell and watch as mitosis and cell division occurs. The cells will go through the steps of interphase, prophase, metaphase, anaphase, telophase, and cytokinesis. The length of the cell cycle can be controlled, and data related to the number of cells present and their current phase can be recorded. 5 Minute Preview

Cell Energy Cycle

Explore the processes of photosynthesis and respiration that occur within plant and animal cells. The cyclical nature of the two processes can be constructed visually, and the simplified photosynthesis and respiration formulae can be balanced. 5 Minute Preview

Chicken Genetics

Breed "pure" chickens with known genotypes that exhibit specific feather colors, and learn how traits are passed on via codominant genes. Chickens can be stored in cages for future breeding, and the statistics of feather color are reported every time the chickens breed. Punnett squares can be used to predict results. 5 Minute Preview

Mouse Genetics (One Trait)

Breed "pure" mice with known genotypes that exhibit specific fur colors, and learn how traits are passed on via dominant and recessive genes. Mice can be stored in cages for future breeding, and the statistics of fur color are reported every time a pair of mice breed. Punnett squares can be used to predict results. 5 Minute Preview

Mouse Genetics (Two Traits)

Breed "pure" mice with known genotypes that exhibit specific fur and eye colors, and learn how traits are passed on via dominant and recessive genes. Mice can be stored in cages for future breeding, and the statistics of fur and eye color are reported every time a pair of mice breed. Punnett squares can be used to predict results. 5 Minute Preview

Microevolution

Observe the effect of predators on a population of parrots with three possible genotypes. The initial percentages and fitness levels of each genotype can be set. Determine how initial fitness levels affect genotype and allele frequencies through several generations. Compare scenarios in which a dominant allele is deleterious, a recessive allele is deleterious, and the heterozygous individual is fittest. 5 Minute Preview

Natural Selection

You are a bird hunting moths (both dark and light) that live on trees. As you capture the moths most easily visible against the tree surface, the moth populations change, illustrating the effects of natural selection. 5 Minute Preview

Rainfall and Bird Beaks

Study the thickness of birds' beaks over a five-year period as you control the yearly rainfall on an isolated island. As the environmental conditions change, the species must adapt (a real-world consequence) to avoid extinction. 5 Minute Preview

Human Evolution - Skull Analysis

Compare the skulls of a variety of significant human ancestors, or hominids. Use available tools to measure lengths, areas, and angles of important features. Each skull can be viewed from the front, side, or from below. Additional information regarding the age, location, and discoverer of each skull can be displayed. 5 Minute Preview

Pollination: Flower to Fruit

Label a diagram that illustrates the anatomy of a flower, and understand the function of each structure. Compare the processes of self pollination and cross pollination, and explore how fertilization takes place in a flowering plant. 5 Minute Preview

Seed Germination

Perform experiments with several seed types to see what conditions yield the highest germination (sprouting) rate. Three different types of seeds can be studied, and the temperature, water and light in the germination chamber can be controlled. No two trials will have the same result so repeated trials are recommended. 5 Minute Preview

Food Chain

In this ecosystem consisting of hawks, snakes, rabbits and grass, the population of each species can be studied as part of a food chain. Disease can be introduced for any species, and the number of animals can be increased or decreased at any time, just like in the real world. 5 Minute Preview

Plants and Snails

Study the production and use of gases by plants and animals. Measure the oxygen and carbon dioxide levels in a test tube containing snails and elodea (a type of plant) in both light and dark conditions. Learn about the interdependence of plants and animals. 5 Minute Preview

Cell Energy Cycle

Explore the processes of photosynthesis and respiration that occur within plant and animal cells. The cyclical nature of the two processes can be constructed visually, and the simplified photosynthesis and respiration formulae can be balanced. 5 Minute Preview

Rock Cycle

Play the role of a piece of rock moving through the rock cycle. Select a starting location and follow many possible paths throughout the cycle. Learn how rocks are formed, weathered, eroded, and reformed as they move from Earth's surface to locations deep within the crust. 5 Minute Preview

Water Cycle

Control the path of a drop of water as it travels through the water cycle. Many alternatives are presented at each stage. Determine how the water moves from one location to another, and learn how water resources are distributed in these locations. 5 Minute Preview

Food Chain

In this ecosystem consisting of hawks, snakes, rabbits and grass, the population of each species can be studied as part of a food chain. Disease can be introduced for any species, and the number of animals can be increased or decreased at any time, just like in the real world. 5 Minute Preview

Porosity

Pour water on a variety of sediment samples to find how much water can be absorbed by the sample (porosity) and how easily water flows through the sample (permeability). 5 Minute Preview

Water Cycle

Control the path of a drop of water as it travels through the water cycle. Many alternatives are presented at each stage. Determine how the water moves from one location to another, and learn how water resources are distributed in these locations. 5 Minute Preview

Circulatory System

Trace the path of blood through a beating heart and the network of blood vessels that supplies blood to the body. Take blood samples from different blood vessels to observe blood cells and measure the levels of oxygen, carbon dioxide, sugar, and urea. 5 Minute Preview

Disease Spread

Observe the spread of disease through a group of people. The methods of transmission can be chosen and include person-to-person, airborne, and foodborne as well as any combination thereof. The probability of each form of transmission and number of people in the group can also be adjusted. 5 Minute Preview

Virus Lytic Cycle

Release a lytic virus in a group of cells and observe how cells are infected over time and eventually destroyed. Data related to the number of healthy cells, infected cells, and viruses can be recorded over time to determine the time required for the virus to mature within a cell. 5 Minute Preview