If you have time, then you can consolidate your understanding by making some notes about each of the learning outcomes in your notebook. Answer In general, they are very large animals - think of the rhinoceros and the elephant. So here thermoregulation is achievable by behavioural means. To get themselves up into the canopy of a the crew used a catapult to fire a fishing line 100 metres into the uppermost branches. They have a different alarm call for each enemy and Attenborough demonstrates this by placing a stuffed leopard nearby.
In Africa, Attenborough encounters a group of orphaned that are being prepared for their return to the wild. This episode concentrates on marine dwellers. In most forms of mammalian reproduction, a blastocyst would undergo such implantation without significant delay - indeed, in humans it's seen as marking the beginnings of true pregnancy. The domestication of led to and then to. In reality, they are mostly different types of protein - just one of a range of large molecules i.
If possible, you should do each activity as you come to it; the text that follows it assumes you have done so. In this process, usable energy and some heat are released. And how long have monotremes existed? Here's the rectangular boney plate from the back of a crocodile. One of the first people to do such a thing was Simon King, 0:51:20 0:51:27 who worked with another creature that lives beside rivers and burrows holes in the bank. In marsupials, this contact is loose and seldom any more than a very rudimentary 'placenta of sorts'. Answer The metabolic rates for mammals and the humming-bird are much higher than those for the fish and reptiles.
The terms 'marsupial' and 'placental' were established in the late 18th century when mammals were first classified. What are the apparent benefits that the development of a more elaborate placenta can bring? You may find that the accompanying text 'talks you through' the diagram step by step, as it does here. Towards the end of its time in the pouch, when the rate of the youngster's growth is very high and energy demands greatest, the fat content of the milk in many species reaches a maximum. The fact that a mammal or bird keeps its body temperature at a high level 37 °C - degrees Celsius - for humans ensures that metabolism proceeds at a high and efficient rate, allowing the sustained and elevated pace of life typical of mammals. A modest-sized lizard - for example the common European lizard - in sunny conditions, can warm from 15 °C close to the recorded air temperature to 25 °C in about five minutes by basking side-on to the sun. I'll now say more about one of the defining features of mammals - milk production. Between these temperatures, there would be no change, therefore, in the amount of heat produced as a by-product of metabolism.
Attenborough visits the forests of , where the are able to differentiate between the of the and the : eating the latter and storing the former. It also shows how they have adapted this talent to help them make their homes and even live underground, as well as revealing their ability to store food — and their ability to breed prolifically. Metabolism is the technical name given to the sum total of all the chemical transformations inside cells. What makes this struggle more remarkable is that these predators do not prey on animals — but on plants. As it got closer to the South Pole, so it got colder, became covered with snow and ice 0:39:02 0:39:09 and its animal inhabitants died out. These demands explain why lactation is a very considerable 'investment' by the mother in the wellbeing of her offspring. In , the differences between and sea lions are illustrated: the former don't have the external ears or the mobility on land of the latter.
Among the most prolific to do so are and. What we see is a successful reproductive strategy or rather a range of strategies, because the details vary between different marsupial species that is very different from our own. Indeed, it's the existence of these common features that justifies the inclusion of all such diverse types within the single taxonomic group or class called the Mammalia. Given that feeding is relatively effortless, the youngster's energy can be largely channelled into growth. For example, rhinoceros milk contains hardly any fat, while seal milk is almost 50% fat. Using his burgeoning intelligence, this most successful of all mammals has exploited the environment to produce food for an ever-increasing population.
Towards the upper part of the cell, closest to the lumen, there are a number of fluid-filled droplets called vesicles , containing what look like small granules. Given that the energy fat content of koalas' milk is comparatively low, it's not surprising that the period of lactation in koalas is unusually long, even by marsupial standards. Fiction with biological themes — explores a future where babies are engineered and to have genetic flaws means you are a second-class citizen — to save a town, doctors must find a virus and a cure before it is too late. When a bear was too inquisitive he was able to command it to turn away simply by raising his hands. There are two graphs in this section, and.
It provides an illustration of how early man pursued his prey with no weapons. In this section, you are presented with a fairly complex diagram,. This suggests that there's another component to responses of the type evident in. Rather than shuffling along, with splayed-out limbs in the manner of many reptiles, this animal had limbs that were more erect and aligned under the body. Food for Thought not broadcast In conclusion a programme about our closest animal relatives, the intelligent great apes, and finds out how their large brains enabled one of their kind, an upright ape, to go on to dominate the planet. .