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The Hypothalamus: The Body's Thermostat (Human Thermostat)

By: HWC, Views: 8116

Normal body function requires a relatively constant body temperature, which is regulated by the body's thermostat, a region of the brain called the hypothalamus. The hypothalamus generates a temperature set point for the body and appears to be the major site for the integration of temperature inf...

Pressure Flow Model Animation

By: HWC, Views: 8140

This apparatus of beakers A and funnels simulates the flow of a sucrose solution in the phloem of a plant. The funnels and connecting tube represent a sieve tube of the phloem. Differentially permeable membranes cap the funnels at the source and sink ends, allowing water, but not sucrose, to cros...

Mendel's Pea Experiment

By: HWC, Views: 8295

Sugar snap peas were common garden plants during Mendel's lifetime and many varieties undoubtedly grew in the abbey gardens. An avid gardener. this is where Mendel first made observations about pea plants. He noticed that certain characteristics of peas were passed from generation to generation. ...

Cognitive development by Piaget (Preoperational stage or intelligence)

By: HWC, Views: 8080

The next stage of cognitive development proposed by Piaget, is the preoperational stage, roughly between the ages of 2 and 7. At this stage Piaget asserted that a child has what he called preoperational intelligence. hey can mentally representing objects, but do not have a system for organising...

Interspecific Competition Relationship - Competitive & Niche Differentiation

By: HWC, Views: 8614

In an environment with limited resources, any organisms that utilize the same resources will be in competition with each other. For example, let's look at two competing species of paramecium, a single-celled organism that feeds on bacteria. If we raise each of these species in isolation, both...

Mechanisms for chromosome movement Animation

By: HWC, Views: 5873

At mitotic metaphase, the fully-formed spindle is composed of many microtubules that extend from the poles. Some of these, the kinetochore microtubules, are attached to the kinetochores of each chromosome. Kinetochores are located at the centromeres. At anaphase, sister chromatids separate and...

Natural Selection, Species Isolation and Real World Example

By: HWC, Views: 8337

`Natural selection' is the process in which organisms with adaptive traits survive and breed in greater number than organisms without such traits. Eventually, almost all of the individuals in the population will have the same adaptive trait. This was the concept presented by Charles Darwin in ...

Darwin's Observation (Fossils, Galapagos Islands & Africa ) and Natural Selection (Adaptive Traits)

By: HWC, Views: 8753

Along Darwin's voyage, he made many observations. Each one added to his understanding of how organisms change over time. Darwin was already familiar with fossils and knew that many fossils were very different from living organisms. But, also there were some fossils that were very similar to li...

SNP Polymorphysim Microarray Chip - How to Test a Person's DNA

By: HWC, Views: 8222

To test a person's DNA, a researcher first needs a source of tissue. Most of the cells in a blood sample are red blood cells, which lack nuclei, but there are also a number of white blood cells, which do contain nuclei and chromosomal DNA. If we could see a particular DNA sequence in these cel...