Giant flowers

The titan arum (Amorphophallus titanum) has the largest unbranched inflorescence, which can be over 3 meters high. The titan arum is indigenous to the equatorial rainforests of Sumatra, Indonesia. To attract pollinators, it gives off a fragrance that smells like a decomposing mammal. Each titan arum has a single gigantic leaf that can be 6 meters tall and 5 meters across. 

Rafflesia arnoldii produces the largest individual flower on earth. This species occurs only in Sumatra and Borneo, Indonesia. The flower of R. arnoldii can be 1 meter across and weigh 11 kilograms. R. arnoldii shares the nickname "corpse flower" with the titan arum. Lacking any observable leaves, stems or even roots, R. arnoldii lives as a parasite. Similar to fungi, Rafflesia individuals grow as thread-like strands of tissue completely embedded within and in intimate contact with surrounding host cells from which nutrients and water are obtained.   

These two plants have impressively massive reproductive organs. The largest reproductive organ of all, however, belongs to the Tailpot palm (Corypha umbraculifera) of South Asia. This large palm bears a 6-8 m long branched inflorescence consisting of up to several million flowers. C. umbraculifera flowers only once. The plant dies after fruiting. 

Diatoms

Diatoms, mighty microscopic algae, have profound influence on climate, producing 20 percent of the oxygen we breathe by capturing atmospheric carbon and in so doing, countering the greenhouse effect. Since their evolutionary origins these photosynthetic wonders have come to acquire advantageous genes from bacterial, animal and plant ancestors enabling them to thrive in today's oceans.

These organisms represent a veritable melting pot of traits—a hybrid of genetic mechanisms contributed by ancestral lineages of plants, animals, and bacteria, and optimized over the relatively short evolutionary timeframe of 180 million years since they first appeared. Gene transfer between diatoms and other organisms has been extremely common, making diatoms 'transgenic by nature'.

From plants, the diatom inherited photosynthesis, and from animals the production of urea. It is speculated that the diatom uses urea to store nitrogen, not to eliminate it like animals do, because nitrogen is a precious nutrient in the ocean. What's more, the tiny alga draws the best of both worlds—it can convert fat into sugar, as well as sugar into fat—extremely useful in times of nutrient shortage.

The lifestyle of diatoms can be characterized as "bloom or bust." When light and nutrient conditions in the upper reaches of the ocean are favorable, particularly at the onset of spring, diatoms gain an edge and tend to dominate their phytoplankton brethren. When food is scarce, they die and sink, carrying their complement of carbon dioxide to the deeper recesses.

Bonobos Hunt And Eat Other Primates, Too

Unlike the male-dominated societies of their chimpanzee relatives, bonobo (pigmy chimpanzee)  society—in which females enjoy a higher social status than males—has a "make-love-not-war" kind of image. While chimpanzee males frequently band together to hunt and kill monkeys, the more peaceful bonobos were believed to restrict what meat they do eat to forest antelopes, squirrels, and rodents.

Not so, according to a recently published study that offers the first direct evidence of wild bonobos hunting and eating the young of other primate species.

Bonobos live only in the lowland forest south of the river Congo, and, along with chimpanzees, they are humans' closest relatives. Bonobos are perhaps best known for their promiscuity: sexual acts both within and between the sexes are a common means of greeting, resolving conflicts, or reconciling after conflicts.

The researchers made the discovery that these free-loving primates also hunt and kill other primates.

The researchers have now seen three instances of successful hunts in which bonobos captured and ate their primate prey. In two other cases, the bonobo hunting attempts failed. The data showed that both bonobo sexes play active roles in pursuing and hunting monkeys. The involvement of adult females in the hunts (which is not seen in chimps) may reflect social patterns such as alliance formation and cooperation among adult females.

Overall, the discovery challenges the theory that male dominance and aggression must be causally linked to hunting behavior, an idea held by earlier models of the evolution of aggression in human and non-human primates. Future work on the bonobos may shed light on the social and ecological conditions that encourage their monkey-hunting expeditions, yielding insight into the evolutionary significance and causes of aggression, hunting, and meat eating in bonobos, chimpanzees, and ourselves.

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The deadly dozen

Many wildlife pathogens have been the focus of monitoring efforts, but few data exist on how diseases will spread in response to climate change. The following list includes those pathogens that may spread as a result of changing temperatures and precipitation levels. Monitoring efforts for these diseases need to be examined in tandem with meteorological data to uncover climate-related trends. The list is not a comprehensive one, and subsequent studies may eliminate pathogens from the list of those enabled by climatic factors.

Avian influenza: Like human influenza, avian influenza viruses occur naturally in wild birds, though often with no dire consequences. The virus is shed by infected birds via secretions and feces. Poultry may contract the virus from other domestic birds or wild birds. A highly pathogenic strain of the disease—H5N1—is currently a major concern for the world's governments and health organizations, specifically because it has proven deadly to domestic and wild birds, as well as humans, and has the potential to evolve into a strain that can spread from human to human. Current data indicate that the movement of H5N1 from region to region is largely driven by the trade in poultry, but changes in climate such as severe winter storms and droughts can disrupt normal movements of wild birds and can bring both wild and domestic bird populations into greater contact at remaining water sources.

Babesiosis: Babesia species are examples of tick-borne diseases that affect domestic animals and wildlife, and Babesiosis is an emerging disease in humans. In some instances, Babesia may not always cause severe problems by themselves but when infections are severe due to large numbers of ticks, the host becomes more susceptible to other infectious diseases. This has been seen in large die-offs of lions in East Africa due to canine distemper. Climate factors fostered heavy infestations of ticks on wild buffalo and subsequent spill-over infection of lions. The lions then became more susceptible to infections with the distemper virus. In Europe and North America, the disease is becoming more common in humans, also linked with tick distributions. Diseases that have previously been thought to have limited impact, such as babesiosis, must be watched closely in a changing climate to assess how environmental conditions may tip the scale and cause more significant impacts on ecosystems, animals, and people.

Cholera: Cholera is a water-borne diarrheal disease affecting humans mainly in the developing world. It is caused by a bacterium, Vibrio cholerae, which survives in small organisms in contaminated water sources and may also be present in raw shellfish such as oysters. Once contracted, cholera quickly becomes deadly. It is highly temperature dependent, and increases in water temperature are directly correlated with occurrence of the disease. Rising global temperatures due to climate change are expected to increase incidence of this disease.

Ebola: Ebola hemorrhagic fever virus and its closely related cousin—the Marburg fever virus—easily kill humans, gorillas, and chimpanzees, and there is currently no known cure. Scientists continue to work on finding the source of the disease and to develop vaccines for protection. There is significant evidence that outbreaks of both diseases are related to unusual variations in rainfall/dry season patterns. As climate change disrupts and exaggerates seasonal patterns, we may expect to see outbreaks of these deadly diseases occurring in new locations and with more frequency. WCS's work on Ebola in Central Africa has been supported by the US Fish and Wildlife Service.

Intestinal and external parasites: Parasites are widespread throughout terrestrial and aquatic environments. As temperatures and precipitation levels shift, survival of parasites in the environment will increase in many places, infecting an increasing number of humans and animals. Many species of parasites are zoonotic, spread between wildlife and humans. The nematode, Baylisascaris procyonis, is spread by the common raccoon and is deadly to many other species of wildlife and humans. A close relative, Baylisascaris schroederi, causes death in its natural host—the critically endangered giant panda. Monitoring of parasite species and loads in wildlife and livestock help us identify transmission of these infections between domestic and wild animals and humans.

Lyme disease: This disease is caused by a bacterium and is transmitted to humans through tick bites. Tick distributions will shift as a result of climate change, bringing Lyme disease into new regions to infect more animals and people. Although effects of the disease on wildlife have not been documented, human-induced changes in the environment and on population patterns of species such as white-tailed deer that can carry infective ticks greatly affect the distribution of this disease. Monitoring of tick distributions will be necessary to assess the impacts of climate change on this disease.

Plague: Plague, Yersinia pestis—one of the oldest infectious diseases known—still causes significant death rates in wildlife, domestic animals, and humans in certain locations. Plague is spread by rodents and their fleas. Alterations in temperatures and rainfall are expected to change the distribution of rodent populations around the globe, which would impact the range of rodent-born diseases such as plague.

"Red tides": Harmful algal blooms off global coasts create toxins that are deadly to both humans and wildlife. These occurrences—commonly called "red tides"—cause mass fish kills, marine mammal strandings, penguin and seabird mortality, and human illness and death from brevetoxins, domoic acid, and saxitoxins (the cause of "paralytic shellfish poisoning"). Similar events in freshwater are caused by a species of Cyanobacteria and have resulted in animal die-offs in Africa. Altered temperatures or food-web dynamics resulting from climate change will have unpredictable impacts on the occurrences of this worldwide phenomenon. Effects of harmful algal blooms on sea life are often the first indicators that such an event is taking place.

Rift Valley Fever: Rift Valley fever virus (RVFV) is an emerging zoonotic disease of significant public health, food security, and overall economic importance, particularly in Africa and the Middle East. In infected livestock such as cattle, sheep, goats and camels, abortions and high death rates are common. In people (who can get the virus from butchering infected animals), the disease can be fatal. Given the role of mosquitoes in transmission of the virus, changes in climate continue to be associated with concerns over the spread of RVFV.

Sleeping sickness: Also known as trypanosomiasis, this disease affects people and animals. It is caused by the protozoan, Trypanosoma brucei, and transmitted by the tsetse fly. The disease is endemic in certain regions of Sub-Saharan Africa, affecting 36 countries, with estimates of 300,000 new cases every year and more than 40,000 human deaths each year in eastern Africa. Domestic cattle are a major source of the disease, but wildlife can be infected and maintain the disease in an area. Direct and indirect effects (such as human land-use patterns) of climate change on tsetse fly distributions could play a role in the distribution of this deadly disease.

Tuberculosis: As humans have moved cattle around the world, bovine tuberculosis has also spread. It now has a global distribution and is especially problematic in Africa, where it was introduced by European livestock in the 1800s. The disease infects vital wildlife populations, such as buffalo and lions in Kruger National Park in South Africa, where tourism is an integral part of local economies. The disease also infects humans in southern Africa through the consumption of un-pasteurized milk. Human forms of tuberculosis can also infect wild animals. Climate change impacts on water availability due to drought are likely to increase the contact of wildlife and livestock at limited water sources, resulting in increased transmission of the disease between livestock and wildlife and livestock and humans.

Yellow fever: Found in the tropical regions of Africa and parts of Central and South America, this virus is carried by mosquitoes, which will spread into new areas as changes in temperatures and precipitation levels permit. One type of the virus—jungle yellow fever—can be spread from primates to humans and vice-versa via mosquitoes that feed on both hosts. Recent outbreaks in Brazil and Argentina have had devastating impacts on wild primate populations. In some countries in South America, monitoring of wild primates has resulted in early detection of disease activity and allowed vaccination programs to be rapidly implemented to protect humans.

How did farmers conquer the world?

For most of the time since the ancestors of modern humans diverged from the ancestors of the living great apes, all humans on Earth fed themselves exclusively by hunting wild animals and gathering wild plants. It was only within the last 11,000 years that some peoples turned to what is termed food production: that is, domesticating wild animals and plants and eating the resulting livestock and crops. Today, most people on Earth consume food that they produced themselves or that someone else produced for them.

 

Different peoples acquired food production at different times in prehistory. Some, such as Aboriginal Australians, never acquired it at all. Of those who did, some (for example, the ancient Chinese) developed it independently by themselves, while others (including ancient Egyptians) acquired it from their neighbors.

 

Availability of more consumable calories means more people. Among wild plant and animal species, only a small minority are edible to humans or worth hunting/gathering. Most species are useless to us as food, for one or more of the following reasons: they are indigestible (like bark), poisonous, low in nutritional value, tedious to prepare, difficult to gather, or dangerous to hunt. Most biomass on land is in the form of wood and leaves, most of which we cannot digest (the giant panda, a carnivore with a vegetarian diet, faces pretty much the same set of problems).

 

By selecting and growing those few species of plants and animals that we can eat, we obtain far more edible calories per unit land area. As a result, one hectare can feed many more herders and farmers--typically, 10 to 100 times more--than hunter-gatherers. That strength of brute numbers was the first of many military advantages that food-producing tribes gained over hunter-gatherer tribes.

 

In human societies possessing domestic animals, livestock fed more people in four distinct ways: by furnishing meat, milk, and fertilizer and by pulling plows. First and most directly, domestic animals became the societies' major source of animal protein, replacing wild game. In addition, some big domestic mammals served as sources of milk and of milk products such as butter, cheese, and yogurt. Those mammals thereby yield several times more calories over their lifetime than if they were just slaughtered and consumed as meat. Animal manure was and remains a major source of crop fertilizer. Plow pulling mammals enabled people to till lands that were otherwise uneconomical for farming.

 

Infectious diseases like smallpox, measles, bubonic plague, tuberculosis, and influenza mutated from similar ancestral pathogens that had infected group-living animals. The humans who domesticated animals were the first to fall victim to the newly evolved germs, but those humans then evolved substantial resistance to the new diseases. When such partly immune people came into contact with others who had had no previous exposure to the pathogens, epidemics resulted in which up to 99 percent of the previously unexposed population was killed. Infectious diseases thus acquired ultimately from domestic animals played decisive roles in the European conquests of Native Americans, Australians, South Africans, and Pacific islanders. 

The spread of humans

We come from a long line of failures. We are apes, a group that almost went extinct fifteen million years ago in competition with the better-designed monkeys. We are primates, a group that almost went extinct forty-five million years ago in competition with the better designed rodents. We are chordates, a phylum that survived in the Cambrian era 500 million years ago by the skin of its teeth in competition with the brilliantly successful arthropods. Our ecological success came against humbling odds.

 

The out of Africa hypothesis suggests all living humans evolved from a group that originated in Africa. It postulates that modern Homo sapiens spread out of Africa, into Europe and Asia, and replaced archaic Homo sapiens living in those regions. This hypothesis is supported by molecular data. In contrast, the multiregional hypothesis posits that the archaic Homo sapiens populations in the different regions (Europe, Asia, and Africa) all evolved together into modern Homo sapiens. While genetic changes would first occur in one locality, gene flow would spread those changes into the other localities.

 

Human history took off around 50,000 years ago, at the time of what is sometimes termed our Great Leap Forward. The earliest definite signs of that leap come from East African sites with standardized stone tools and the first preserved jewelry. Similar developments soon appeared in the Near East and in southeastern Europe, then (some 40,000 years ago) in southwestern Europe, where abundant artifacts are associated with fully modern skeletons of people.

 

The great leap forward coincides with the first proven major extension of human geographic range since our ancestors’ colonization of Eurasia. That extension consisted of the occupation of Australia and New Guinea, joined at that time into a single continent. Many archeological sites attest to human presence in Australia/New Guinea between 40,000 and 30,000 years ago. Within a short time of that initial peopling, humans had expanded over the whole continent and adapted to its diverse habitats, from the tropical rain forests and high mountains of New Guinea to the dry interior and wet southeastern corner of Australia.

 

With the settlement of Australia/New Guinea, humans occupied three of the five habitable continents (Eurasia is counted as a single continent). That left only two continents, North America and South America. The Americas were first settled around 11,000 B.C. and quickly filled up with people.