south of 72°N), where they are decreasing in numbers due to unsustainable hunting, warming temperatures caused by climate change and disturbance from increased boat traffic (NAMMCO, 2019). >> The global Red List lists narwhals as Least Concern, while the Greenland red list considers them Nearly Threatened in West Greenland and Endangered in East Greenland. This emphasizes the need to understand the function of nervous systems, including brains, at the level of neural circuits rather than in terms of size. /G3 11 0 R Organisms differ radically in life histories. /StructParents 0 Like the sperm bundles in the monotremes, the aggregation of rodent spermatozoa appears to improve motility for more efficient passage through the female tract. The estimated numbers of blue whales in southern hemisphere habitats range from 400 to 1400 (all subspecies combined). /GS7 41 0 R It is fibroelastic like those of the blue whale's artiodactyl relatives. William Harvey used extensive dissections of animals and cadavers to delineate the nuances of the circulatory system (Harvey, 1962); the history of biological research is replete with such examples. In most eutherians the acrosome covers approximately the anterior 2/3 rds of the sperm head as a cap-like structure. In both vertebrates and insects, brain size scales with body mass but individual species may have relatively larger or smaller brains. << Relative brain size is a post hoc measure with no theoretical basis, chosen solely because it is a measure that ranks humans higher than other mammals. (a) Tropical rainforest along the Kinabatangan River in Borneo. Hippocampal volume is implicated in behavioral performance on spatial memory tasks, suggesting that birds that store food have a larger hippocampus because they retain spatial memories of their food stores. >> Paper [13] employs two types of neural networks (based on competitive learning and Kohonen feature mapping respectively) in order to analyze the repertoire of false killer whale vocalizations. The discovery of the molecular structure of DNA by Francis Watson and James Crick (1952) triggerred an explosion in gene mapping (the underlining fabric of life on Earth), along with an improved understanding of the mechanism of speciation, and how the genetic variability of a species can be the difference between persistence or extinction. One of the most striking differences between nervous systems is their size (measured as weight or volume) – the brain of a blue whale weighs up to 9 kg while that of a locust weighs less than a gram (Figure 5). The reproductive phase starts at first reproduction and includes the distribution of all periods of potential reproduction thereafter. By some estimates, research that focuses on delaying aging could increase human life expectancy by 2.2 years for every 1 year of gain in life expectancy that would be generated by similarly funded cancer or cardiovascular research (Goldman et al., 2013). There are concerns that their spread constitutes the introduction of invasive genomes (Role of Engineering Plants for Abiotic Stresses). Mammals regulate their internal temperature (endothermy). The survey effort required to collect data sufficiently powerful for trend detection is prohibitively costly. Increasing demands from wealthy nations for wood products from cloud forests (Tropical Montane Cloud Forests), together with unprecedented climate changes, are also placing these irreplaceable forests at the brink of collapse. << >> The energy available for computation and for supporting the brain at rest is dependent upon the specific metabolic rate of neural tissue. P.A. For instance, classic experiments in Drosophila melanogaster demonstrated that longevity could be selected for by only allowing old flies to reproduce such that the force of natural selection did not decrease with age (Luckinbill and Clare, 1985; Rose, 1989). Peter Zahler, Tatjana Rosen, in Encyclopedia of Biodiversity (Second Edition), 2013. Beluga: Belugas and narwhals belong to the same family, Monodontidae, and can produce hybrids (Skovrind et al., 2019). 3 Specifically, climate vulnerability (Climate Vulnerability: Understanding and Assessing Threats to Essential Resources) is the vulnerability of a particular species or ecosystem to climatic factors extending outside the historic climate envelope. /GS3 38 0 R During 2016–18, a yearly average of 204 belugas were landed in West Greenland (http://nammco.no). /ML 4 /Prop1 << Habitat Change – as humanity expands its ecological footprint nearly everywhere around the globe, we transform the habitats of countless species, benefiting some – usually generalists with wide ranging habitat tolerances and high fecundity rates – while pushing others to the brink of extinction (Extirpation and Exinction). /X3 50 0 R /Title <4C617965722031C2A0496D616765> 12 0 obj All blue whale populations and subspecies are listed as “endangered” pursuant to ESA and “endangered” as per RLTS, throughout their respective geographic ranges. In eutherians, a complex maturation of spermatozoa occurs as they transit the epididymis. The Antarctic blue whale (B. musculus intermedia (Burmeister, 1871)) summers in the Antarctic Ocean, and the northern blue whale (B. musculus musculus (Linnaeus, 1758)) is found in the North Pacific and North Atlantic.