Earth formed about 4. Microbial mats of coexisting bacteria and archaea were the dominant form of life in the early Archean. The evolution of oxygenic photosynthesis , around 3. The earliest evidence of eukaryotes complex cells with organelles , dates from 1. The earliest land plants date back to around Ma million years ago , although evidence suggests that algal scum formed on the land as early as 1. Land plants were so successful that they are thought to have contributed to the late Devonian extinction event. Invertebrate animals appear during the Vendian period, while vertebrates originated about Ma during the Cambrian explosion.
Snakes use an infrared heat-sensing system to hunt down their prey, scientists believe. They have special pits located between their eyes and nostrils that can sense minute temperature changes as infrared rays, as an aid in locating warm-blooded prey such as rodents. Now researchers have come up with a chemical explanation for this amazing ability to detect infrared radiation that has mystified them for decades.
Use this activity to increase pupil’s knowledge of specialised cells. Pupils become an expert on one type of cell and have to share their knowledge with others, whilst gathering information about other specialised cells.
Distinguishing characteristics[ edit ] Salticidae male anterior and dorsal aspects, showing positions of eyes Jumping spiders are among the easiest to distinguish from similar spider families because of the shape of the cephalothorax and their eye patterns. The families closest to Salticidae in general appearance are the Corinnidae distinguished also by prominent spines on the back four legs , the Oxyopidae the lynx spiders, distinguished by very prominent spines on all legs , and the Thomisidae the crab spiders, distinguished by their front four legs, which are very long and powerful.
None of these families however, has eyes that resemble those of the Salticidae. Conversely, the legs of jumping spiders are not covered with any very prominent spines. Their front four legs generally are larger than the hind four, but not as dramatically so as those of the crab spiders, nor are they held in the outstretched-arms attitude characteristic of the Thomisidae.
The generally larger front legs are used partly to assist in grasping prey,  and in some species, the front legs and pedipalps are used in species-recognition signalling. The jumping spiders, unlike the other families, have faces that are roughly rectangular surfaces perpendicular to their direction of motion.
In effect this means that their forward-looking, anterior eyes are on “flat faces”, as shown in the photographs. Their eye pattern is the clearest single identifying characteristic. They have eight eyes, as illustrated.
Background[ edit ] Although related to the more general problem of the origin of language , the evolution of distinctively human speech capacities has become a distinct and in many ways separate area of scientific research. Speech is in this sense optional, although it is the default modality for language. Places of articulation passive and active: Sub-apical Uncontroversially, monkeys, apes and humans, like many other animals, have evolved specialised mechanisms for producing sound for purposes of social communication.
The angular gyrus is represented in orange, supramarginal gyrus is represented in yellow, Broca’s area is represented in blue, Wernicke’s area is represented in green and the primary auditory cortex is represented in pink.
1, Likes, 19 Comments – MIT Architecture (@mitarchitecture) on Instagram: “A quick tour through a review in the Geometric Disciplines course for first year students, ”.
Many bands are bounded along their margins by an individual ridge, suggesting that a double ridge was split along its axis during band formation Fig. Where the bands pulled apart, dark, probably low-viscosity subsurface material moved up to fill the gap. Limited topographic data across bands suggest that many stand somewhat higher than the surrounding terrain, consistent with formation by upwelling buoyant ice, rather than liquid water.
Bands have been shown to have brightened over time, possibly because of frost deposition or radiation damage, leading to a wide range of brightnesses ranging from relatively dark, through gray, to as bright as the brightest background plains on the surface. Points along a large gray band arrows, top can be reconstructed if the band is removed arrows, bottom , with the preexisting terrain matching up perfectly along the margins.
The band appears to have exploited two existing double ridges during its formation. Reconstructions like this show that a completely new surface has been created by band formation, suggesting that they represent a considerable amount of extension of Europa’s surface. After Prockter et al. Morphological comparisons between bands and terrestrial midocean ridges suggest that band formation may have been analogous to seafloor spreading centers on the Earth, where plates are pulled apart and new volcanic material erupts along the spreading axis.
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Human timeline and Nature timeline Primitive protocells were the precursors to today’s unicellular organisms. Although the origin of life is largely still a mystery, in the currently prevailing theory, known as the RNA world hypothesis , early RNA molecules would have been the basis for catalyzing organic chemical reactions and self-replication. Theoretical and experimental findings show that nucleic acids and sugars could have been synthesized in early prebiotic conditions.
For example, an early RNA replicator ribozyme may have replicated other replicator ribozymes of different RNA sequences if not kept separate.
Chromosome segregation during cell division is like speed dating, according to Geisel School of Medicine at Dartmouth researcher Duane Compton. He and postdoctoral fellow Lilian Kabeche learned that protein cyclin A plays moderator, helping to properly separate chromosomes via the attachment of microtubule fibers to kinetochore structures.
Mike Hanlon October 23rd, October 23, The online dating scene incorporates about sites and generates about 1. As this is such a large industry, it is forever trying to come up with more efficient algorithms for putting compatible parties together both time- and cost- efficiently and facilitating effective communication between the parties. Two new web sites named Yesnomayb and eHarmony Marriage joined the ranks recently and both differentiate themselves very effectively in this space.
Online dating is big business for the major players who have client bases in the ten million range. Dating site EHarmony focuses on facilitating communication between potential partners and is now extending its relationship skills services to catering to married couples with programmes designed to facilitate a more harmonious marriage.
A quick look at the online dating scene shows a myriad of systems designed to facilitate a happy ending in brokering short, medium and long term relationships between human beings. The most comprehensive resource seemingly niche area incorporates about sites and generates about 1. Dating sites are just one facet of the computer-mediated meeting marketplace which introduces suitable partners for a range of endeavours.
Be it business or some other narrowly defined common interest, long term relationship or a sexual partner, the internet is quickly moving forward in its algorithms for putting compatible parties together both time- and cost- efficiently. Interesting contender number one is Yesnomayb. The method of compatibility assessment mimics that of the real world on-line speed dating process in that the yesnomayb judgements used in determining a match are based on attractiveness.
Basically, you sort a list of photos and classify the people you see into yes, no and maybe, and your picture is also seeded into the photos seen by potential matches — corresponding yesses puts the respondees in touch. The market Currently, Match. Each service has its own speciality be it better matching, more choice, strength in a particular ethnic audience, safe methodologies and vetting of partners.
Allergy Science: From Antibodies to Anaphylaxis
The team of researchers at the ARC Centre for Excellence in Plant Energy Biology and the Centre for AgriBioscience at La Trobe University, have boosted plant performance under limited phosphate by targeting genes that regulate phosphate transport in plant roots, resulting in increased phosphate uptake while sidestepping negative effects on plant growth and yield. The approach overcomes a hurdle encountered by previous attempts to increase plant phosphate uptake, where reduced growth and yield were observed as a result of plants not being able to process the extra phosphate.
The discovery would be even more valuable in China where overuse of fertilisers is a huge environmental and economic issue. There is also great interest in the United States where the findings were published.
List of fallacious creationist quotes. From RationalWiki. Jump to: navigation, search. The divine comedy Creationism: ask yourself: Does it seem reasonable that all the amazingly complex cells, waste products, metal ions and so on. These specialised channels involve highly specific proteins, molecules that could not have been present at.
In the UK, 58 women are diagnosed with a gynaecological cancer every day Image: Getty Get daily news updates directly to your inbox Subscribe Thank you for subscribingWe have more newsletters Show me See our privacy notice Could not subscribe, try again laterInvalid Email Over 21, women in the UK are diagnosed with a gynaecological cancer each year — but do you know what this actually is?
However, once you know what to look for, early detection can save lives. Excess oestrogen is one cause — and because fat carries more of this, being overweight is also a risk. The cervix A smear test Image: Signs Again, unexpected bleeding is an important sign, particularly if it occurs after intercourse. Treatment A colposcopy examines the cervix, and a small tissue sample may be removed for testing. If caught early, the affected skin can be removed.
If not, you could need surgery, or a combination of chemo and radiotherapy. The signs These symptoms will typically last persistently for three weeks or more: Your GP will do a blood test, looking for a particular enzyme produced when the peritoneal cavity is inflamed. Treatment If the biopsy reveals cancer, treatment will usually involve surgery, followed by several cycles of chemotherapy.
Don’t be afraid to ask your doctor, if you notice anything unusual Image: Everyone is different, so it pays to be familiar with the area, so you know if something looks unusual.
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The reasoning is thus: A cat has little ability to sense its absolute speed which makes sense, since any good relativist will tell you that there’s no such thing as an “absolute speed”. What a cat does have is a sense of proprioception, which tells the cat how fast it’s accelerating. When a cat falls out of a window it begins accelerating at something close to 9. Specifically, it tucks its head in, pulls its feet under its body, and curves its spine.
This page will have Daily Check-In questions so that you know what you have learned and what you still need help with. The question sets will stay up all semester so that you can use them to study!
Circulatory system The circulatory system comprises the heart and blood vessels arteries , veins and capillaries. The heart propels the circulation of the blood, which serves as a “transportation system” to transfer oxygen , fuel, nutrients, waste products, immune cells and signalling molecules i. The blood consists of fluid that carries cells in the circulation, including some that move from tissue to blood vessels and back, as well as the spleen and bone marrow.
It converts food into small, nutritional, non-toxic molecules for distribution and absorption into the body. Endocrine system The endocrine system consists of the principal endocrine glands: The endocrine hormones serve as signals from one body system to another regarding an enormous array of conditions, and resulting in variety of changes of function. Immune system The immune system consists of the white blood cells , the thymus , lymph nodes and lymph channels, which are also part of the lymphatic system.
The immune system provides a mechanism for the body to distinguish its own cells and tissues from outside cells and substances and to neutralize or destroy the latter by using specialized proteins such as antibodies , cytokines , and toll-like receptors , among many others. Integumentary system The integumentary system consists of the covering of the body the skin , including hair and nails as well as other functionally important structures such as the sweat glands and sebaceous glands.
The skin provides containment, structure, and protection for other organs, and serves as a major sensory interface with the outside world.
Raised and now employed at a family-run funeral home in north Texas, she has seen and handled dead bodies on an almost daily basis since childhood. Now 28 years old, she estimates that she has worked on something like 1, bodies. Her work involves collecting recently deceased bodies from the Dallas—Fort Worth area and preparing them for their funeral. He had been relatively healthy for most of his life. He had worked his whole life on the Texas oil fields, a job that kept him physically active and in pretty good shape.
He had stopped smoking decades earlier and drank alcohol moderately.
The latest work focused on mesenchymal stem cells (MSC), which are naturally produced by the body and have the potential to change into specialised cell types such as bone, cartilage, ligament.
Intro is still unclear with respect to conservation status[ edit ] Yet, the world’s only population of wild dromedaries are in Australia. In addition to being grammatically incorrect should be ” Can someone please clear this up? Considering that they are more or less self-sustaining without human intervention. The dromedary is listed as ‘extinct in the wild’ by the IUCN because every remaining dromedary is either domesticated or feral, neither of which is considered wild.
If it is, it belongs in the article on the Bactrian Camel , not here. Since no Bactrian camels exist in Northern Africa, the writing must be wrong.