相关实验视频

Updated: Feb 11, 2026

A Noninvasive Hair Sampling Technique to Obtain High Quality DNA from Elusive Small Mammals
07:40

A Noninvasive Hair Sampling Technique to Obtain High Quality DNA from Elusive Small Mammals

Published on: March 13, 2011

21.4K

四年纪后期哺乳动物的体型下降

Felisa A Smith1, Rosemary E Elliott Smith2, S Kathleen Lyons3

  • 1Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA. fasmith@unm.edu.

Science (New York, N.Y.)
|April 21, 2018
PubMed
概括

大型哺乳动物的灭绝是由人类活动驱动的, 这种前所未有的趋势正在重塑地球的生物圈,

更多相关视频

Experimental Manipulation of Body Size to Estimate Morphological Scaling Relationships in Drosophila06:00

Experimental Manipulation of Body Size to Estimate Morphological Scaling Relationships in Drosophila

Published on: October 1, 2011

14.4K
Using Deuterium Oxide as a Non-Invasive, Non-Lethal Tool for Assessing Body Composition and Water Consumption in Mammals08:22

Using Deuterium Oxide as a Non-Invasive, Non-Lethal Tool for Assessing Body Composition and Water Consumption in Mammals

Published on: February 20, 2020

8.0K

相关概念视频

Cell Size01:22

Cell Size

Cell sizes vary widely among and within organisms. Bacterial cells range between 1-10 micrometers (μm)and are considerably smaller than most eukaryotic cells. The smallest bacteria are 0.1 μm in diameter—about a thousand times smaller than eukaryotic cells, which typically range from 10-100 μm.
Surface Area
Cells can take in nutrients and water via diffusion through the plasma membrane itself or through specific channels in the membrane. The area of the membrane surrounding...
132.0K
Brick Sizes01:21

Brick Sizes

Brick sizing plays a crucial role in construction, influencing both the aesthetics and structural integrity of buildings. Bricks are defined by three dimensions: width, thickness, and length. They are commonly designed to fit modular measurements, typically in multiples of 4 inches or 8 inches in width, to facilitate uniform construction and compatibility with other building materials.
Modular bricks are the most common type and are sized to include the mortar joint, which is essential for...
352
Genome Size and the Evolution of New Genes03:21

Genome Size and the Evolution of New Genes

While every living organism has a genome of some kind (be it RNA, or DNA), there is considerable variation in the sizes of these blueprints. One major factor that impacts genome size is whether the organism is prokaryotic or eukaryotic. In prokaryotes, the genome contains little to no non-coding sequence, such that genes are tightly clustered in groups or operons sequentially along the chromosome. Conversely, the genes in eukaryotes are punctuated by long stretches of non-coding sequence.
9.2K
Body Temperature01:25

Body Temperature

The body's temperature, measured in degrees, is determined by the balance between heat production and dissipation to the surrounding environment. For instance, if exercising vigorously, the body will produce more heat, causing sweat and dissipating that heat. Despite extreme environmental conditions and physical exertion, the human temperature-control system maintains a constant core body temperature (the temperature of deep tissues, which are the tissues located beneath the skin and other...
4.9K
Body Temperature01:07

Body Temperature

Body temperature reflects the equilibrium between heat production and heat loss within the body. Most heat is generated by metabolically active tissues, particularly the liver, heart, brain, kidneys, and endocrine organs. At rest, skeletal muscles contribute 20–30% of total heat production, but during vigorous exercise, this can increase up to 30–40 times.
The average body temperature is approximately 37°C (98.6°F) and typically ranges from 36.1–37.2°C...
1.5K
Centroid of a Body01:16

Centroid of a Body

The centroid is an important concept in engineering, physics, and mechanics. It is the geometric center of a body. It always lies within the body except in cases with holes or cavities. When the material that a body is composed of is uniform or homogeneous, the centroid coincides with its center of mass or the center of gravity.
For a homogeneous body with constant density, the centroid can usually be found using equations representing a balance of the moments of the body's volume. If the...
1.9K