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This is done both on a microscopic and molecular level as it encompasses prokaryotic cells and eukaryotic cells. Knowing the components of cells and how cells work is fundamental to all biological sciences ; it is also essential for research in bio-medical fields such as cancer , and other diseases. Biology Cell Structure Function And Metabolism Bk 2 Form And Function Biology Form And Function Research in cell biology is closely related to genetics , biochemistry , molecular biology , immunology , and cytochemistry. For some extra information, the recommendation is to check the biology resource in the external link. Cells, which were once invisible to the naked eye, were first seen in 17th century Europe with the invention of the compound microscope.
Animals vary in form and function. From a sponge to a worm to a goat, an organism has a distinct body plan that limits its size and shape. Animal body plans follow set patterns related to symmetry. They are asymmetrical, radial, or bilateral in form as illustrated in Figure Asymmetrical animals are animals with no pattern or symmetry; an example of an asymmetrical animal is a sponge.
Radial symmetry, as illustrated in Figure This plan is found mostly in aquatic animals, especially organisms that attach themselves to a base, like a rock or a boat, and extract their food from the surrounding water as it flows around the organism.
Bilateral symmetry is illustrated in the same figure by a goat. The goat also has an upper and lower component to it, but a plane cut from front to back separates the animal into definite right and left sides.
Additional terms used when describing positions in the body are anterior frontposterior reardorsal toward the backand ventral toward the stomach. Bilateral symmetry is found in both land-based and aquatic animals; it enables a high level of mobility.
The exchange of nutrients and wastes between a cell and its watery environment occurs through the process of diffusion.
All living cells are bathed in liquid, whether they are in a single-celled organism or a multicellular one. Diffusion is effective over a specific distance and limits the size that an individual cell can attain. If a cell is a single-celled microorganism, such as an amoeba, it can satisfy all of its nutrient and waste needs through diffusion.
If the cell is too large, then diffusion is ineffective and the center of the cell does not receive adequate nutrients nor is it able to effectively dispel its waste.
An important concept in understanding how efficient diffusion is as a means of transport is the surface to volume ratio. Recall that any three-dimensional object has a surface area and volume; the ratio of these two quantities is the surface-to-volume ratio.
Apr 4, Biology: Cell Structure, Function and Metabolism Bk. 2: Form and Function. Paperback. Volume editor Norman Cohen. Share. Exploring how.
The larger the size of the sphere, or animal, the less surface area for diffusion it possesses. The solution to producing larger organisms is for them to become multicellular. Specialization occurs in complex organisms, allowing cells to become more efficient at doing fewer tasks. For example, circulatory systems bring nutrients and remove waste, while respiratory systems provide oxygen for the cells and remove carbon dioxide from them.
Other organ systems have developed further specialization of cells and tissues and efficiently control body functions. Moreover, surface-to-volume ratio applies to other areas of animal development, such as the relationship between muscle mass and cross-sectional surface area in supporting skeletons, and in the relationship between muscle mass and the generation of dissipation of heat.
Visit this interactive site to see an entire animal a zebrafish embryo at the cellular and sub-cellular level. Use the zoom and navigation functions for a virtual nanoscopy exploration.
All animals must obtain their energy from food they ingest or absorb. These nutrients are converted to adenosine triphosphate ATP for short-term storage and use by all cells. Some animals store energy for slightly longer times as glycogen, and others store energy for much longer times in the form of triglycerides housed in specialized adipose tissues. If an animal can conserve that heat and maintain a relatively constant body temperature, it is classified as a warm-blooded animal and called an endotherm.
The insulation used to conserve the body heat comes in the forms of fur, fat, or feathers. The absence of insulation in ectothermic animals increases their dependence on the environment for body heat. The amount of energy expended by an animal over a specific time is called its metabolic rate.
The rate is measured variously in joules, calories, or kilocalories calories. Carbohydrates and proteins contain about 4. Metabolic rate is estimated as the basal metabolic rate BMR in endothermic animals at rest and as the standard metabolic rate SMR in ectotherms. Even with insulation, endothermal animals require extensive amounts of energy to maintain a constant body temperature.
Smaller endothermic animals have a greater surface area for their mass than larger ones Figure Therefore, smaller animals lose heat at a faster rate than larger animals and require more energy to maintain a constant internal temperature.
This results in a smaller endothermic animal having a higher BMR, per body weight, than a larger endothermic animal. Humans are more sedentary than most animals and have an average daily rate of only 1. The diet of an endothermic animal is determined by its BMR. For example: the type of grasses, leaves, or shrubs that an herbivore eats affects the number of calories that it takes in.
Animals adapt to extremes of temperature or food availability through torpor.
Torpor is a process that leads to a decrease in activity and metabolism and allows animals to survive adverse conditions. Torpor can be used by animals for long periods, such as entering a state of hibernation during the winter months, in which case it enables them to maintain a reduced body temperature. If torpor occurs during the summer months with high temperatures and little water, it is called estivation.
Some desert animals use this to survive the harshest months of the year. Torpor can occur on a daily basis; this is seen in bats and hummingbirds. While endothermy is limited in smaller animals by surface to volume ratio, some organisms can be smaller and still be endotherms because they employ daily torpor during the part of the day that is coldest.
This allows them to conserve energy during the colder parts of the day, when they consume more energy to maintain their body temperature. A standing vertebrate animal can be divided by several planes.
A sagittal plane divides the body into right and left portions. A midsagittal plane divides the body exactly in the middle, making two equal right and left halves. A frontal plane also called a coronal plane separates the front from the back. A transverse plane or, horizontal plane divides the animal into upper and lower portions. This is sometimes called a cross section, and, if the transverse cut is at an angle, it is called an oblique plane.
Figure Vertebrate animals have a number of defined body cavities, as illustrated in Figure Two of these are major cavities that contain smaller cavities within them. Biology Cell Structure Function And Metabolism Bk 2 Form And Function Biology Form And Function dorsal cavity contains the cranial and the vertebral or spinal cavities.
The ventral cavity contains the thoracic cavity, which in turn contains the pleural cavity around the lungs and the pericardial cavity, which surrounds the heart. The ventral cavity also contains the abdominopelvic cavity, which can be separated into the abdominal and the pelvic cavities. Physical anthropologists study the adaption, variability, and evolution of human beings, plus their living and fossil relatives.
They can work in a variety of settings, although most will have an academic appointment at a university, usually in an anthropology department or a biology, genetics, or zoology department. Non-academic positions are available in the automotive and aerospace industries where the focus is on human size, shape, and anatomy.
Research by these professionals might range from studies of how the human body reacts to car crashes to exploring how to make seats more comfortable. Other non-academic positions can be obtained in museums of natural history, anthropology, archaeology, or science and technology.
These positions involve educating students from grade school through graduate school. Physical anthropologists serve as education coordinators, collection managers, writers for museum publications, and as administrators. Zoos employ these professionals, especially if they have an expertise in primate biology; they work in collection management and captive breeding programs for endangered species.
Forensic science utilizes physical anthropology expertise in identifying human and animal remains, assisting in determining the cause of death, and for expert testimony in trials. Skip to content Increase Font Size. Unit 4: Animal Structure and Function. Learning Objectives By the end of this section, you will be able to: Describe the various types of body plans that occur in animals.
Energy Requirements Related to Levels of Activity. Energy Requirements Related to Environment. Animal Body Planes and Cavities. Next: License Share This Book.