Animal Sciences

Transient Orcas: A Dying Breed

As the muscular body catapults from the water, the crowd “oohs” and “aahs,” straining against the rails to see the massive fluke slap against the waves. The stutter of camera clicks and flashes ceases, as the admirers wait anxiously for the next opportunity to record their great Alaskan adventure on film. As they continue their sightseeing, the tour guide informs the excited passengers about the killer whales, the mighty king of the seas. Each summer many vacationers migrate to Alaska to see the rugged scenery and magnificent wildlife.

The Circadian Clock Regulates Auxin Signaling and Responses in Arabidopsis

Plants, which as sessile organisms are intimately tied to their environment, have evolved many ways to deal with changing local conditions. One coping mechanism is the circadian oscillator or clock, which produces self-sustained rhythms with an approximately 24-h period. It is often suggested that the clock provides an adaptive advantage by allowing organisms to anticipate regular changes in the environment and temporally separate incompatible metabolic events.

Systemic Bud Induction and Retinoic Acid Signaling Underlie Whole Body Regeneration in the Urochordate Botrylloides leachi

Some of the most fundamental issues in developmental biology concern the ability of metazoans to regenerate. In most multicellular organisms, adult stem cells maintain organs’ homeostasis throughout life and facilitate tissue repair after injury or disease [1]. Several organisms are capable of regrowing amputated organs and body parts, for example, amphibian limbs, lens, and retina.

Forest Elephant Crisis in the Congo Basin

Between 1970 and 1989, half of Africa’s elephants (Loxodonta africana), perhaps 700,000 individuals, were killed, mostly to supply the international ivory trade. This catastrophic decline prompted the Conference of the Parties (CoP) to the Convention on the International Trade in Endangered Species of Wild Flora and Fauna (CITES) to list African elephants on Appendix I of the convention, banning the international ivory trade.

Flight Speeds among Bird Species: Allometric and Phylogenetic Effects

A full evaluation of the applicability of aerodynamic scaling rules must be based, not on theoretically derived speeds, but on empirical measurements of airspeeds of a wide variety of bird species in natural cruising flight. Here, we present tracking radar measurements of flight speeds of 138 species from six main monophyletic groups, which were analysed in relation to biometry (m, S, and wingspan b) and evolutionary origin (as reflected by phylogenetic group).

Development of rat female genital cortex and control of female puberty by sexual touch

Early analysis of the development of visual cortex by Hubel and Wiesel focused on binocular interactions and showed that both anatomy and physiology of ocular dominance is plastic and shaped in a visually-driven, activity-dependent process [1]. In a similar vein, the development of circuits in the somatosensory cortex (S1) was studied. It was recognized early on that precise topographic (barrel) representation of the whisker pattern in cortical input layer 4 [2] is imposed by peripheral inputs and has an early and brief critical period, after which it can no longer be changed [3].

Critical Status of the Brown Bear

Tourists visit Alaska with visions of postcard-perfect wildlife and scenery dancing through their heads. They expect to see brown bears plucking salmon out of the beautiful and majestic Kenai River. The problem with this vision is the possible decline of brown bears on the Kenai Peninsula in the not-to-distant future.

The Effects of Environmental Factors on the Action Potentials of Earthworms

Pesticides have helped improve the standard of living for millions of people around the world however their use has been linked to numerous ecological problems such as damaging the nervous systems of non-target organisms including humans. The purpose of this experiment is to determine the effects various environmental factors can have on the nervous systems of earthworms.

A fat-derived metabolite regulates a peptidergic feeding circuit in Drosophila

Animals must balance food intake with energy expenditure to maintain optimal health. In choosing what and how much to eat, animals integrate external cues like tastes and smells with internal motivational states like hunger and satiety. Powerful homeostatic mechanisms tie these motivational states to the sensing of nutrient and energy status. Because fat is the primary long-term energy storage molecule, these homeostatic sensors monitor fat levels—triggering increased feeding when they fall and decreased feeding when they rise.

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