Blog 13 Compare the circulation of a segmented worm a starfish and a grasshopper

Grasshoppers have open circulatory systems, with most of the body fluid filling body cavities and appendages. The one closed organ, the dorsal vessel, extends from the head through the thorax to the hind end. It is a continuous tube with two regions: the heart, which is restricted to the abdomen; and the aorta, which extends from the heart to the head through the thorax. Haemolymph is pumped forward from the hind end and the sides of the body through a series of valved chambers, each of which contains a pair of lateral openings. The haemolymph continues to the aorta and is discharged through the front of the head. Accessory pumps carry haemolymph through the wing veins and along the legs and antennae before it flows back to the abdomen. This haemolymph circulates nutrients through the body and carries metabolic wastes to the malphighian tubes to be excreted. Because it does not carry oxygen, grasshopper blood is green.

The starfish has radial canals that go through all the legs and join in the center to make the water vascular

system that functions as a circulatory system, waste removal and more.

Starfish are almost unique in the fact that, unlike most other animals, they do not have blood but instead use sea water to pump around their bodies. The water vascular system uses cilia and the constantly contracting ampullae to keep things moving. An ionic imbalance causes water to flow into the madreporite, entering the water vascular system. Some of this water is diverted into the periviscerial coelom (the large cavity in which major organs are suspended), where it is circulated by the beating of cilia. Most oxygen enters the starfish via diffusion into the tube feet (with the water vascular system), or the papulae (small sacs covering the upper body surface.There are about 1,800 living species of sea star, and they occur in all of the Earth's oceans. The greatest variety of sea stars are found in the northern Pacific Ocean.

Circulation in a segmented worm is through a series of closed vessels. The two main vessels that can be seen in your dissection are the dorsal and ventral blood vessels. These vessels are the main pumping structures. In the dorsal vessel, blood moves anteriorly. The dorsal vessel is the dark line running along the dorsal surface of the digestive tract. In the posterior third of your worm, carefully cut through and remove about three centimeters of the digestive tract. The ventral blood vessel can usually be seen adhering to the segment of intestine removed. In the ventral vessel, blood moves posteriorly. Segmental branches off the ventral vessel supply the intestine and body wall with blood. These branches eventually break into capillary beds to pick up or release nutrients and, oxygen. Gas exchange occurs between the capillary beds of the body surface and the environment. Oxygen is carried by the respiratory pigment hemoglobin, which is dissolved in the fluid portion of the blood. From these capillary beds, blood is collected into larger vessels that eventually unite with the dorsal vessel. At the level of the esophagus, segmental branches are expanded into five pairs of aortic arches, or what have been called "hearts". They are dark, expanded structures on either side of the esophagus. Although these are contractile, they only function in pumping blood from the dorsal to the ventral vessels.

Blog 12 Compare and contrast the animals and plants you have dissected so far based on one organ system, i.e. reproduction how are they alike?

Well out of all thee animals we have dissected so far thee all have organs and skin. A cray fish has an anus just like a starfish and a worm. They are all located in similar places toward thee bottom of thee animal. However many of thee animals have eyes as well. For example a cray fish has two eyes like a perch however, a grasshopper has 3 eyes called simple eyes. Also in a cray fish they have gills instead of lungs unlike a grasshopper. A grasshopper is a land creature so it has lungs not gills. Only animals who live in water have gilla exception to alligators.

Blog 11 (Double points) Describe your bird experience in terms of competition (More points for vocabulary), food selection and factors that affected t

My bird experience was awsome I obtained a lot food because I had a spoon. I had to fight for thee food I wanted but most of thee time I won becuase i was very aggresive more then thee other birds!:) I did very well getting my food, a spoon beak is the best beak you can have.

Having a spoon was a great advantage it was very easy to get food. Unlike a knife beak however I would of liked to have a fork because it looked easlier to pick up food but a spoon work fine. I was able to get food for myself, enough to last me.

Blog 10: Explain how contamination of one animal in a food web can affect other animals

The terms food chain and food web both refer to groups of organisms that are dependent on each other for food. A food chain is a single series of organisms in which each plant or animal depends on the organism above or below it. As an example, a food chain might consist of garden plants, such as lettuce and carrots, fed upon by rabbits which, in turn, are fed upon by owls which, in turn, are fed upon by hawks.

The feeding relationships of organisms in the real world is almost always more complex than suggested by a food chain. For that reason, the term food web can effect other animals. A food web differs from a food chain in that it includes all the organisms whose feeding habits are related in some way or another to those of other organisms. In the example above, small animals other than rabbits feed on lettuce and carrots and, in turn, those animals are fed upon by a variety of larger animals.

Blog 9 What geologic era do you think was the most important why?

I would choose the mesolithic era is most important because Mesolithic means "Middle Stone Age. However, the prefix "meso-" in the word can mean "between," and this has been taken some scientists to refer to cultures in between a hunter-gathering mode and an agricultural mode. The Mesolithic era begins at the end of the Pleistocene epoch and the start of the Holocene, the most recent geologic epoch. Prior to the Mesolithic era, mile-thick continental glaciers covered most of Eurasia and North America. Any terrain north of 50 °N was essentially uninhabitable, until the ice melted around 11,000 years ago. Global temperatures increased, making life easier for humans worldwide. By the Mesolithic, humans had already spread across the entire world, except for Antarctica and a few remote islands. The Americas and Australia were fully colonized. The Mesolithic era was an unusual transition time between the Paleolithic and the Neolithic. Because the period was relatively short, Mesolithic artifacts are relatively hard to come by, consisting mainly of middens, or scrap-heaps. In coastal areas around the world, there are large shell middens dating to the Mesolithic era. In British Columbia, there is a midden several meters in depth which has been around for at least 10,000 years. Mesolithic cultures were about as advanced as you could get before establishing agriculture and cities. They hunted animals with a variety of bows and spears, and drove most of the world's megafauna to extinction. Like civilizations before them, they survived through a mix of hunting and gathering, although may have begun to intentionally plant the seeds of edible plants in fertile soils, pulling out the weeds.

Blog 8 Give examples of the different types of natural selection. Give an example for each

The different types of natural selection are directional selection, disruptive selection, and Stabilizing selection. In directional selection, one extreme of the trait distribution experiences selection against it. The result is that the population's trait distribution shifts toward the other extreme. In the case of such selection, the mean of the population graph shifts. Using the familiar example of giraffe necks, there was a selection pressure against short necks, since individuals with short necks could not reach as many leaves on which to feed. As a result, the distribution of neck length shifted to favor individuals with long necks.In disruptive selection, selection pressures act against individuals in the middle of the trait distribution. The result is a bimodal, or two-peaked, curve in which the two extremes of the curve create their own smaller curves. For example, imagine a plant of extremely variable height that is pollinated by three different pollinators, one that was attracted to short plants, another that preferred plants of medium height and a third that visited only the tallest plants. If the pollinator that preferred plants of medium height disappeared from an area, medium height plants would be selected against and the population would tend toward both short and tall, but not medium height plants. Stabilizing selection is when natural selection works against the two extremes of a trait to make the population more uniform. For example, stabilizing selection might work on the birth weight of human babies to keep them at an intermediate weight, because babies that are too big or too small have less chance of being born healthy.

Blog 7 What was dangerous about Darwin's idea?

Darwin's theory was revolutionary because it banished the concept of intelligent design from biology, consigning it to a marginal theological ghetto. For the first time, there seemed to be a plausible materialistic explanation for all those ingenious biological mechanisms -- the brain and the eye, digestion and circulation, feathers and fins.

Others extended Darwin's ban on intelligent design to include the origin of life and the universe itself. With help from intellectuals such as Marx and Freud, we were left with a view of humans as mere animals or machines who inhabit a universe ruled by chance, and whose behavior and thoughts are determined by the immutable and impersonal forces of nature and environment.