This reduced the likelihood of fertilization by unwanted aggressors in favor of fitter mates. įemales have corkscrew vaginas with many blind pockets designed for difficult penetration and to prevent becoming pregnant. Studies have shown that the longer a male's phallus is, the more elaborate the vaginal structures were. The clockwise coils are significant because the male phallus everts out of their body in a counter-clockwise spiral therefore, a clockwise vaginal structure would impede forceful copulation. These structures make it harder for males to achieve intromission. The male waterfowl evolution of a phallus to forcefully copulate with females has led to counteradaptations in females in the form of vaginal structures called dead end sacs and clockwise coils. The phallus that male waterfowl have evolved everts out of their bodies (in a clockwise coil) and aids in inseminating females without their cooperation. Most birds mate with the males balancing on top of the females and touching cloacas in a "cloacal kiss" this makes forceful insemination very difficult. While most male birds have no external genitalia, male waterfowl ( Anatidae) have a phallus. The lake duck (also called Argentine blue-bill) has the largest penis in relation to body size of all vertebrates while usually about half the body size (20 cm), a specimen with a penis 42.5 cm long is documented. It is usually partially feathered and in some species features spines and brush-like filaments, and in flaccid state curls up inside the cloaca. A bird penis is different in structure from mammal penises, being an erectile expansion of the cloacal wall and being erected by lymph, not blood. Among bird species with a penis are paleognathes ( tinamous and ratites) and Anatidae (ducks, geese and swans). Most male birds (e.g., roosters and turkeys) have a cloaca (also present on the female), but not a penis. In most species of animals in which there is an organ that might reasonably be described as a penis, it has no major function other than intromission, or at least conveying the sperm to the female, but in the placental mammals the penis bears the distal part of the urethra, which discharges both urine during urination and semen during copulation. Even within the Vertebrata there are morphological variants with specific terminology, such as hemipenes. As an example, the intromittent organ of most cephalopoda is the hectocotylus, a specialized arm, and male spiders use their pedipalps. The term penis applies to many intromittent organs, but not to all. Such organs occur in many animals, both vertebrate and invertebrate, but males do not bear a penis in every animal species, and in those species in which the male does bear a so-called penis, the penises in the various species are not necessarily homologous. To view any of the lessons below click on link.A penis (plural penises or penes ( /- n iː z/)) is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Lessons and exercises that are related different types of weather You can click on the printer icon just below and to the right of the contact us menu button at the top of the page or copy and paste the part of the exercise you want onto a word document and then print onto some paper. To print the lesson on the different types of weather vocabulary list with pictures right click on a white space and choose print. Print the English lesson on different types of weather It is freezing today make sure you wear your hat and gloves when you go out. Rainbows are so beautiful with all the different colours. Tomorrow it is going to be windy lets make a kite today. Talking about the different types of weather
Types of weather vocabularyįor some of the picture is the word for type of weather and the word used when talking about that type of weather.
#4 pics 1 word 5 letters level 1379 how to
After the pictures are examples of how to talk about weather in a basic sentence. This English lesson you will be able to learn about the different types of weather using pictures with the name for each type of weather underneath. Types of weather vocabulary with pictures English lesson Types of weather vocabulary Different kinds of weather
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