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October, 2006
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Parturition: The process of giving birth to one or more offspring.

A Novel Method for Involving Women of Color at High Risk for Preterm Birth in Research Priority Setting

1School of Nursing, University of California, San Francisco, 2UCSF California Preterm Birth Initiative, University of California, San Francisco, 3School of Medicine, University of California, San Francisco, 4San Francisco Black Infant Health Program, 5Homeless Prenatal Program, San Francisco, CA

JoVE 56220


Population Growth- Concept

JoVE 10605

Population Models

An ecological population is a group of individuals of a single species living in an area at the same time. To persist, a population must either grow or maintain its size. Population ecology is the study of how population size and age distribution change over time through interactions with other species and the environment as well as with individuals of their own…

 Lab Bio


JoVE 10915

Behavioral imprinting is observed in some newborn animals and occurs when they develop strong and specific attachments to another animal (usually a parent) following brief, early-life exposures. Offspring imprint onto parents within a brief period after birth or hatching; this time window is called the critical period. Once imprinting occurs, the bond established between the parents and their offspring is usually long-lasting. Mother sheep imprint onto the scent of their lambs within a few hours after their birth. Since many females in the herd give birth at the same time of year, imprinting allows the mothers to selectively recognize and care for their lambs. Imprinting also occurs in the opposite direction, with offspring imprinting onto their parents. This is particularly common in waterfowl, such as goslings (baby geese), which imprint onto their mother on the first day after hatching. Afterward, they follow the mother wherever she goes. This behavior allows the mother to protect her offspring and teach them the skills they need to survive. In the 1930s, Konrad Lorenz showed that goslings imprint onto the first large, moving object they see during the critical period. In the absence of their mother, this object could be siblings, a person, or even an inanimate object. After that, they will always follow this substitute “mother,”

 Core: Biology

Natural Selection- Concept

JoVE 10632


Widespread variation of phenotypes in natural populations provides the raw material for evolution, which is the change in the inherited traits of populations over successive generations. Natural selection is one of the main mechanisms of evolution and requires variable traits to be heritable and associated with differential survival and/or reproductive success. Phenotypes that…

 Lab Bio

Reproductive Cloning

JoVE 10816

Reproductive cloning is the process of producing a genetically identical copy—a clone—of an entire organism. While clones can be produced by splitting an early embryo—similar to what happens naturally with identical twins—cloning of adult animals is usually done by a process called somatic cell nuclear transfer (SCNT).

In SCNT, an egg cell is taken from an animal and its nucleus is removed, creating an enucleated egg. Then a somatic cell—any cell that is not a sex cell—is taken from the animal to be cloned. The nucleus of the somatic cell is then transferred into the enucleated egg—either by direct injection or by fusion of the somatic cell to the egg using an electrical current. The egg now contains the nucleus, with the chromosomal DNA, of the animal to be cloned. It is stimulated to divide, forming an embryo, which is then implanted into the uterus of a surrogate mother. If all goes well, it develops normally and the clone is born. Although this process has been used to successfully clone many different types of animals—including sheep, cows, mules, rabbits, and dogs—its success rate is low, with only a small percentage of embryos surviving to birth. Cloned animals that survive to birth also appear to age and die prematurely. This is because their DNA comes from adult cells that have unde

 Core: Biology

The Sense of Self: Reflected Self-Appraisal and Social Comparison

JoVE 11037

According to Charles Cooley, we base our image on what we think other people see (Cooley 1902). We imagine how we must appear to others, then react to this speculation. We don certain clothes, prepare our hair in a particular manner, wear makeup, use cologne, and the like—all with the notion that our presentation of ourselves is going to affect how others perceive us. We expect a certain …

 Core: Psychology

Anatomy of the Intestines

JoVE 10830

Although digestion of proteins, carbohydrates, and lipids may begin in the stomach, it is completed in the intestine. The absorption of nutrients, water, and electrolytes from food and drink also occur in the intestine. The intestines can be divided into two structurally distinct organs—the small and large intestines.

The small intestine is an ~22 meter-long tube with an inner diameter of just 2.5 cm. Since most nutrients are absorbed here, the inner lining of the small intestine is highly convoluted and covered in finger-like extensions called villi, each containing hundreds of microvilli. The folds, villi, and microvilli of the small intestine amplify the surface area of absorption 60 to 120 times. The increased surface area provides ample opportunity for nutrients to be absorbed. The small intestine connects to the stomach by the pyloric sphincter, which closes off when chyme moves into the duodenum—the beginning of the small intestine. The middle and largest part of the small intestine is the jejunum. The ileum ends the small intestine, where it attaches to the large intestine by the ileocecal valve. The large intestine starts at the cecum. The appendix, a small lymphatic structure, dangles from the bottom of the cecum. Above the cecum, starts the ascending colon followed by the transverse colon. They absorb most of the remaining

 Core: Biology

Species Distribution and Biogeography- Concept

JoVE 10603

Species Distribution

Biogeography is the study of species distribution across geographic space and the processes that shape these distributions. This discipline is based on the assumption that each species within a location must have immigrated from another geographic area or evolved from a local species. Within each habitat, a variety of biotic and abiotic factors act on…

 Lab Bio

Parental Care

JoVE 10921

Many animals exhibit parental care behavior, including feeding, grooming, and protecting young offspring. Parental care is universal in mammals and birds, which often have young that are born relatively helpless. Several species of insects and fish, as well as some amphibians, also care for their young.

Parental care can occur even before hatching in birds, when parents sit on their eggs to incubate them. After hatching, the parents provide food for their offspring, and may continue to brood their young to keep them warm. Both male and female birds provide parental care, depending on the species. In marsupial mammals, such as kangaroos, the embryos are often born at a very early stage and then crawl into their mother’s pouch. Here, the mother nurses and protects her offspring—sometimes for many months—until it can function more independently. Placental mammals are born more developed than marsupials, but they still require a lot of care. Mammalian parental care is mostly provided by the mother, triggered by the hormones of pregnancy and birth and the necessity of lactation for providing nutrients. Nursing is an essential kind of mammalian parental care since the mother’s milk is the primary source of food for the young. Mammals also often lick their newborns and carry them around—grooming, protecting, and bonding wi

 Core: Biology

Invertebrate Lifespan Quantification

JoVE 5338

Many animals naturally stop growing upon reaching adulthood, after which they undergo aging or "senescence" until dying. The amount of time between an organism\'s birth and death is called its lifespan, which can be influenced by various biological and environmental factors. By exposing organisms to different growth conditions, scientists can better understand the factors affecting lifespan.…

 Developmental Biology
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