THE HIERARCHY OF STRUCTURAL ORGANIZATION IN AN ANIMAL

THE HIERARCHY OF STRUCTURAL ORGANIZATION IN AN ANIMAL
Copyright © 2009 Pearson Education, Inc.

20.1 Structure fits function at all levels of organization in the animal body
Anatomy—structure Physiology—function Animals consist of a hierarchy of levels or organization Teeth are a great example of the relationship between form and function. Cats have sharp teeth well adapted to slicing meat. The blunted teeth of horses and bison crush and grind plant materials. Human teeth represent a compromise of these two extremes. Our rear molars efficiently grind and shred plant materials. Our incisors and canines pierce and slice. Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. When you discuss form and function relationships, ask students to consider their own teeth as an example. Ask them to use their tongues to feel their teeth and relate their shape to the human diet. Incisors and canines slice, while molars are more effective at crushing. Copyright © 2009 Pearson Education, Inc.

20.2 EVOLUTION CONNECTION: An animal’s form reflects natural selection
Sharks, seals, and penguins have streamlined, tapered bodies Student Misconceptions and Concerns 1. As noted in Module 20.2, the use of the term design in biology does not imply conscious invention. Instead, the term identifies the arrangement of the parts and their interrelated functions. Natural selection is not a deliberate process. 2. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 3. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. Students often fail to consider the significance of body size. Consider asking your students to think about the impact of being small. Have they ever had difficulty emerging from a swimming pool because of the adhesive properties of water? Of course not—and yet, small insects that land on a pond’s surface may find these forces to be lethal, preventing them from breaking away from the water’s surface! Ask students if they are ever unable to leave their homes because of high winds, which make it impossible for them to walk around outside. The movements of small insects are often hampered by winds that would do little more than toss around our hair! Many campers know that mosquitoes and flies are less of a nuisance on days when there is a good breeze. Video: Galápagos Sea Lion Video: Shark Eating a Seal Copyright © 2009 Pearson Education, Inc.

Shark Figure 20.2 Convergent evolution of body shape in fast swimmers. Penguin Seal

A Cellular level Muscle cell
Figure 20.1 An example of structural hierarchy in a pelican.

B Tissue level Muscle tissue A Cellular level Muscle cell
Figure 20.1 An example of structural hierarchy in a pelican.

B Tissue level Muscle tissue A Cellular level Muscle cell C
Organ level Heart Figure 20.1 An example of structural hierarchy in a pelican.

Organ level Heart Figure 20.1 An example of structural hierarchy in a pelican. D Organ system level Circulatory system

Organ level Heart Figure 20.1 An example of structural hierarchy in a pelican. D Organ system level Circulatory system E Organism level Many organ systems functioning together

20.3 Tissues are groups of cells with a common structure and function
Animals have four main categories of tissues Epithelial tissue Connective tissue Muscle tissue Nervous tissue Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. Extracellular substances, such as collagen fibers, are the source of the main functional properties of many connective tissues such as tendons, ligaments, cartilage, and bone. Copyright © 2009 Pearson Education, Inc.

20.4 Epithelial tissue covers the body and lines its organs and cavities
Epithelial cells come in three shapes Squamous—like a fried egg Cuboidal—as tall as they are wide Columnar—taller than they are wide Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. Simple squamous cells have a shape that is generally similar to a fried egg: flattened, with a bump in the middle representing the nucleus or yolk. 2. Students might misunderstand how the cilia lining our respiratory passages work. Cilia do not “filter” the air like a comb. Instead, cilia are covered by a layer of mucus. Dust particles adhere to sticky mucus, which is then swept up the respiratory tract by the cilia. If students clear their throats, they will identify the fate of this mucus. We swallow after clearing our throats! Copyright © 2009 Pearson Education, Inc.

Simple squamous epithelium (air sacs of the lung) D Pseudostratified
Apical surface of epithelium Basal lamina Underlying tissue Cell nuclei A Simple squamous epithelium (air sacs of the lung) D Pseudostratified ciliated columnar epithelium (respiratory tract) B Simple cuboidal epithelium (kidney) Figure 20.4 Types of epithelial tissue. E Stratified squamous epithelium (esophagus) C Simple columnar epithelium (intestine)

20.5 Connective tissue binds and supports other tissues
Connective tissue can be grouped into six major types The tissue consists of a matrix which can be hard, semi soft or fluid in which are embedded cells. Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. The elastic cartilage in the human ear is a wonderful example of a form and function relationship. Elastic fibers are abundant in the extracellular matrix, increasing the flexibility of elastic cartilage. Have students bend their own ears to feel the effects. Copyright © 2009 Pearson Education, Inc.

C Adipose tissue D Cartilage (at the end of a bone) B
Fat droplets Cartilage- forming cells C Adipose tissue Matrix Cell nucleus D Cartilage (at the end of a bone) Collagen fibers Central canal B Cell Fibrous connective tissue (forming a tendon) White blood cells Matrix Figure 20.5 Types of connective tissue. Collagen fiber Bone- forming cells Elastic fibers Red blood cell E Bone Plasma A Loose connective tissue (under the skin) F Blood

20.6 Muscle tissue functions in movement
Skeletal muscle causes voluntary movements Cardiac muscle pumps blood Smooth muscle moves walls of internal organs, such as the intestines Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. Muscle cells are only able to contract. None can actively relengthen. Challenge your students to explain how muscle cells return to their extended length. (Answer: Opposing muscles or other forces, such as gravity, act in opposition to relengthen muscle cells when they relax.) Copyright © 2009 Pearson Education, Inc.

Unit of muscle Junction between contraction Muscle two cells Muscle
fiber Muscle fiber Nucleus Nucleus Muscle fiber Nucleus B Cardiac muscle A Skeletal muscle Figure 20.6 The three types of muscle. C Smooth muscle

20.7 Nervous tissue forms a communication network
Neurons carry signals by conducting electrical impulses Supporting cells insulate axons and nourish neurons Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. Students might enjoy this simple observation when discussing neurons. As we consider the structure and functions of neurons, we are using our own neurons to think about them. Copyright © 2009 Pearson Education, Inc.

Cell body Nucleus Figure 20.7 Neurons in the spinal cord.

20.8 Organs are made up of tissues
Each tissue performs specific functions The heart has epithelial, connective, and nervous tissues Epithelia line the heart chambers Connective tissues make the heart elastic Neurons regulate contractions Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. Sponges are well-adapted to maximize surface area exposed to water. Like the small intestine with its many villi, the highly porous structure of sponges dramatically increases the area available for water filtering. Copyright © 2009 Pearson Education, Inc.

(columnar epithelium)
Small intestine Lumen Lumen Epithelial tissue (columnar epithelium) Connective tissue Figure 20.8 Tissue layers of the small intestine wall. Smooth muscle tissue (2 layers) Connective tissue Epithelial tissue

20.9 CONNECTION: Bioengineers are learning to produce tissues and organs for transplants
Artificial skin Used to heal burns Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. As noted in Module 20.9, researchers often use cells derived from newborns’ foreskin. Students may not realize that this is actually the excess tissue removed during circumcision of newborn baby boys. Such tissues are widely available as a by-product of this procedure. Copyright © 2009 Pearson Education, Inc.

Figure 20.9 A laboratory-grown bladder.

20.11 CONNECTION: New imaging technology reveals the inner body
New technologies show body organs without surgery X-rays help to see bones and teeth Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. Module provides an excellent opportunity to discuss the impact of technology on science and medicine. New ways of viewing, detecting, and monitoring our bodies invite additional avenues of inquiry. Copyright © 2009 Pearson Education, Inc.

Figure 20.11 Scans showing bone cancer in two locations in the vertebral column. CT scan.

Magnetic resonance microscopy (MRM) Provides three-dimensional images of very small structures Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. Module provides an excellent opportunity to discuss the impact of technology on science and medicine. New ways of viewing, detecting, and monitoring our bodies invite additional avenues of inquiry. Copyright © 2009 Pearson Education, Inc.

Campbell, Neil A. , Jane B. Reece, Martha R. Taylor, Eric J
Campbell, Neil A., Jane B. Reece, Martha R. Taylor, Eric J. Simon, Biology: Concepts & Connections, 5th ed., Figure 20.11C An MRM scan of a 47-day old human embryo.

Positron-emission tomography (PET) Helps identify metabolic processes at specific body locations Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. Module provides an excellent opportunity to discuss the impact of technology on science and medicine. New ways of viewing, detecting, and monitoring our bodies invite additional avenues of inquiry. Copyright © 2009 Pearson Education, Inc.

Figure 20.11 Scans showing bone cancer in two locations in the vertebral column. PET scan.

Figure Scans showing bone cancer in two locations in the vertebral column. Combined CT-PET scan.

20.10 Organ systems work together to perform life’s functions
An organ system usually consists of many organs Each organ system has one or more functions Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. To help them appreciate the functional integration of the major systems of the body, have students pick any system and discuss its relationship to the other body systems. As a start, you might begin with the circulatory system. As each successive system is covered, you can create a concept map noting the nature of each interrelationship. Copyright © 2009 Pearson Education, Inc.

Endocrine system controls body functions Skeletal and muscular systems support and move the body Circulatory system transports the food and oxygen Respiratory system absorbs oxygen and releases carbon dioxide Integumentary system covers and protects the body Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips To help them appreciate the functional integration of the major systems of the body, have students pick any system and discuss its relationship to the other body systems. As a start, you might begin with the circulatory system. As each successive system is covered, you can create a concept map noting the nature of each interrelationship. For the Discovery Video Human Body, go to Animation and Video Files. Copyright © 2009 Pearson Education, Inc.

C Circulatory system D Respiratory system Nasal cavity Larynx Trachea Heart Bronchus Lung Blood vessels A Endocrine system B Skeletal system Hypothalamus Pituitary gland Bone Thyroid gland Parathyroid gland Adrenal gland Cartilage Pancreas E Muscular system Testis (male) Ovary (female) Figure Human organ systems and their component parts. F Integumentary system Skeletal muscles Hair Nails Skin

Excretory system disposes of certain wastes Lymphatic and immune systems protect the body from infection and cancer Reproductive system perpetuates the species Digestive system absorbs food Nervous system controls body functions Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. To help them appreciate the functional integration of the major systems of the body, have students pick any system and discuss its relationship to the other body systems. As a start, you might begin with the circulatory system. As each successive system is covered, you can create a concept map noting the nature of each interrelationship. Copyright © 2009 Pearson Education, Inc.

G, H Lymphatic and immune systems K Reproductive system Thymus Bone marrow Spleen Lymph nodes Female Male Seminal vesicles Lymphatic vessels Prostate gland Oviduct Vas deferens Ovary Penis Uterus Urethra Vagina Testis I Urinary system Brain Sense organ Mouth J Digestive system Spinal cord Kidney Esophagus L Nervous system Ureter Figure Human organ systems and their component parts. Liver Urinary bladder Stomach Small intestine Nerves Urethra Large intestine Anus

20.12 The integumentary system protects the body
The skin consists of two layers Epidermis, at the surface Dermis, inner layer Student Misconceptions and Concerns 1. Students often find it challenging to gain a proper understanding of the evolution of form and function relationships. Such relationships appear to have been “constructed” to meet a purpose, a consequence of deliberate planning and design. Ask students to explain why we have lungs, and they will typically answer something along the line of “Because we need to breathe,” or “Because we need oxygen.” Need, however, does not cause evolution. Natural selection involves editing rather than creating diversity. A better answer might be “Because lung-like structures conveyed an advantage in gas exchange in our ancestors.” 2. Relationships between form and function are found all around us. For some of us, noticing the connections is easy. However, many students have spent little time considering why any particular structure has its characteristic shape. Practice with examples helps to build a better understanding of these important relationships. Teaching Tips 1. The stratified squamous epithelium on most outside surfaces of our body resists abrasions in part because it is keratinized. However, the nonkeratinized epithelial tissue that lines our body cavities, such as the mouth, pharynx, esophagus, and anus, is also resistant to abrasion as a result of its mucus coatings, which provide friction-reducing lubrication. Students may not realize that the same type of tissue performs similar functions in very different parts of the body. 2. Students might have noticed that their skin wrinkles when soaked in water. Some students may have noticed that their hands wrinkle even faster in soapy water. Skin absorbs water through osmosis (just as a freshwater fish gains water). Oils on our skin reduce the influx of water. Therefore, soapy water, which washes away these oils, speeds up the movement of water into our keratinized skin. The wrinkling occurs because the skin can expand only in certain areas, creating puckers. Copyright © 2009 Pearson Education, Inc.

Hair Epidermis Sweat pore Muscle Dermis Nerve Sweat gland Hypodermis
Figure A section of skin, the major organ of the integumentary system. Sweat gland Hypodermis Adipose tissue Blood vessels Oil gland Hair follicle

20.12 The integumentary system protects the body
Skin has many functions Epidermis Resists damage Decreases water loss Prevents penetration by microbes Dermis Sensory information Synthesis of vitamin D Temperature regulation Copyright © 2009 Pearson Education, Inc.

20.13 Structural adaptations enhance exchange between animals and their environment
Animals must exchange materials with the environment Respiratory system exchanges gases Digestive system acquires food and eliminates wastes Excretory system eliminates metabolic waste Student Misconceptions and Concerns 1. If students have not previously studied the diversity of animals, consider giving a brief overview of the basic animal body plans before explaining how the fundamental principles of form and function generally apply to the animal kingdom. 2. It can be difficult for students to think of their own bodies in terms of simple surfaces and tubes. Perceiving the digestive tract as one continuous tube, in which food passes through but never technically enters the body, is one such challenge. Illustrate these fundamental principles first using less complex animals (such as earthworms) as examples. Then apply these principles to humans as a final test of comprehension. Teaching Tips 1. Large organisms must transport and exchange material throughout their entire structure, including their inner core. This principle applies equally to natural organisms, such as a whale or a redwood tree, and to collective “organisms,” such as the United States. The U.S. railway and highway networks are analogous to animal transport and exchange systems. They move essential products from their point of entry (ocean ports) into the country’s interior, where they can be warehoused or sold. As a result of this system, people who live in the Midwest have access to the same goods as those who live in New York or San Francisco. 2. Organisms as well as individual cells need sufficient exchange and transport systems to support their surface to volume ratios. Cell size is limited, in part, by the ability of a cell to exchange materials efficiently with its surface. Thus, adaptations that increase surface area can permit cells to reach larger sizes. Copyright © 2009 Pearson Education, Inc.

External environment CO2 Food O2 Mouth Animal d Bl oo Respiratory
system Digestive system Interstitial fluid Heart Nutrients Circulatory system Body cells Figure 20.13A Indirect exchange between the environment and the cells of a complex animal. Urinary system Intestine Anus Unabsorbed matter (feces) Metabolic waste products (urine)

20.13 Structural adaptations enhance exchange between animals and their environment
Adaptations that increase surface area promote exchanges with the environment Student Misconceptions and Concerns 1. If students have not previously studied the diversity of animals, consider giving a brief overview of the basic animal body plans before explaining how the fundamental principles of form and function generally apply to the animal kingdom. 2. It can be difficult for students to think of their own bodies in terms of simple surfaces and tubes. Perceiving the digestive tract as one continuous tube, in which food passes through but never technically enters the body, is one such challenge. Illustrate these fundamental principles first using less complex animals (such as earthworms) as examples. Then apply these principles to humans as a final test of comprehension. Teaching Tips 1. Large organisms must transport and exchange material throughout their entire structure, including their inner core. This principle applies equally to natural organisms, such as a whale or a redwood tree, and to collective “organisms,” such as the United States. The U.S. railway and highway networks are analogous to animal transport and exchange systems. They move essential products from their point of entry (ocean ports) into the country’s interior, where they can be warehoused or sold. As a result of this system, people who live in the Midwest have access to the same goods as those who live in New York or San Francisco. 2. Organisms as well as individual cells need sufficient exchange and transport systems to support their surface to volume ratios. Cell size is limited, in part, by the ability of a cell to exchange materials efficiently with its surface. Thus, adaptations that increase surface area can permit cells to reach larger sizes. Copyright © 2009 Pearson Education, Inc.

20.14 Animals regulate their internal environment
Homeostasis is an internal steady state Student Misconceptions and Concerns 1. If students have not previously studied the diversity of animals, consider giving a brief overview of the basic animal body plans before explaining how the fundamental principles of form and function generally apply to the animal kingdom. 2. The concept of homeostasis may be new to many students who have never considered how organisms maintain their structure and physiology. Analogies to other systems that engage in self-regulation (noted in the text and below) can help. Teaching Tips 1. The heat generated by aerobic metabolism is analogous to the heat generated by the engine of an automobile. In both cases, the heat is a by-product of the process. In the winter, this excess heat helps keep the body and an automobile warm. In the summer, both the body and the automobile’s engine must work to keep from overheating. 2. Ask students to explain how blood vessel constriction near the body’s surface, shivering, and a general increase in metabolism help a person to keep warm in a cold environment. 3. Have students list the many factors that affect heat gain and loss during periods of physical activity in order to demonstrate how hard our homeostatic mechanisms must work to maintain a steady body temperature. These factors include (a) the person’s physical condition, (b) the level of physical activity, (c) the age of the person (younger people tend to have higher metabolic rates), (d) the person’s level of hydration (which in turn affects the amount of sweating and evaporative cooling), (e) the external level of humidity (higher levels decrease evaporative cooling), (f) the intensity of the wind (greater intensity promotes evaporative cooling), (g) the intensity of sunlight, and (h) the color of the person’s clothing (which affects the amount of light energy the body absorbs). Copyright © 2009 Pearson Education, Inc.

Figure 20.14A A white-tailed ptarmigan in its snowy habitat.

External environment Internal environment Homeostatic mechanisms Small
fluctuations Figure 20.14B A model of homeostasis. Large fluctuations

20.14 Animals regulate their internal environment
Humans promote homeostasis by Adding clothing when we are cold Drinking water when we are dehydrated Eating when our calories are running low Urinating when our bladders are full Student Misconceptions and Concerns 1. If students have not previously studied the diversity of animals, consider giving a brief overview of the basic animal body plans before explaining how the fundamental principles of form and function generally apply to the animal kingdom. 2. The concept of homeostasis may be new to many students who have never considered how organisms maintain their structure and physiology. Analogies to other systems that engage in self-regulation (noted in the text and below) can help. Teaching Tips 1. The heat generated by aerobic metabolism is analogous to the heat generated by the engine of an automobile. In both cases, the heat is a by-product of the process. In the winter, this excess heat helps keep the body and an automobile warm. In the summer, both the body and the automobile’s engine must work to keep from overheating. 2. Ask students to explain how blood vessel constriction near the body’s surface, shivering, and a general increase in metabolism help a person to keep warm in a cold environment. 3. Have students list the many factors that affect heat gain and loss during periods of physical activity in order to demonstrate how hard our homeostatic mechanisms must work to maintain a steady body temperature. These factors include (a) the person’s physical condition, (b) the level of physical activity, (c) the age of the person (younger people tend to have higher metabolic rates), (d) the person’s level of hydration (which in turn affects the amount of sweating and evaporative cooling), (e) the external level of humidity (higher levels decrease evaporative cooling), (f) the intensity of the wind (greater intensity promotes evaporative cooling), (g) the intensity of sunlight, and (h) the color of the person’s clothing (which affects the amount of light energy the body absorbs). Copyright © 2009 Pearson Education, Inc.

Animation: Negative Feedback Animation: Positive Feedback
20.15 Homeostasis depends on negative feedback Negative feedback mechanisms permit only small fluctuations around set points For the BLAST Animation Negative Feedback: Body Temperature, go to Animation and Video Files. Student Misconceptions and Concerns 1. If students have not previously studied the diversity of animals, consider giving a brief overview of the basic animal body plans before explaining how the fundamental principles of form and function generally apply to the animal kingdom. 2. The concept of homeostasis may be new to many students who have never considered how organisms maintain their structure and physiology. Analogies to other systems that engage in self-regulation (noted in the text and below) can help. Teaching Tips 1. Challenge your students to think of other examples of negative and positive feedback. Students from diverse disciplines may think of many new examples. Animation: Negative Feedback Animation: Positive Feedback Copyright © 2009 Pearson Education, Inc.

Internal body temperature
Sweat glands secrete sweat that evaporates, cooling body Thermostat in brain activates cooling mechanisms Blood vessels in skin dilate and heat escapes Temperature decreases Thermostat shuts off cooling mechanisms Temperature rises above normal Homeostasis: Internal body temperature of approximately 36–38°C Temperature increases Thermostat shuts off warming mechanisms Temperature falls below normal Figure Control of body temperature. Blood vessels in skin constrict, minimizing heat loss Skeletal muscles rapidly contract, causing shivering, which generates heat Thermostat in brain activates warming mechanisms

Tissue Epithelial (20.4) Connective (20.5) Muscle (20.6)
Nervous (20.7) Sheets of closely packed cells Sparse cells in extracellular matrix Long cells (fibers) with contractile proteins Neurons with branching extensions Structure Protection, exchange, secretion Binding and support of other tissues Movement of body parts Transmission of nerve signals Function

a. b. c. d. e.

You should now be able to
Explain the relationship between anatomy and physiology Describe the structural hierarchy of the body from cell to organism Explain how an animal’s form is influenced by its environment Describe an example of convergent evolution Describe the general structures and functions of the major tissues of the human body Copyright © 2009 Pearson Education, Inc.

You should now be able to
Describe several recent advances of bioengineering List and describe the functions of the major systems of the body Explain how materials are exchanged between an organism and its environment Define homeostasis and describe several examples Copyright © 2009 Pearson Education, Inc.

THE HIERARCHY OF STRUCTURAL ORGANIZATION IN AN ANIMAL

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THE HIERARCHY OF STRUCTURAL ORGANIZATION IN AN ANIMAL

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Presentation on theme: "THE HIERARCHY OF STRUCTURAL ORGANIZATION IN AN ANIMAL"— Presentation transcript:

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About project

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