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Basic Principles

Secret of owl's rotating head! Secret of owl’s rotating head! Owls can rotate their necks a maximum of 270 degrees without breaking blood vessels or tearing tendons! People and other animals can simply move their eyes to follow an object. Owls have fixed eye sockets, which means their eyeballs can’t rotate, forcing them to stretch their necks–a seemingly supernatural feat. Owls are more flexible than humans because a bird’s head is only connected by one socket pivot. People have two, which limits our ability to twist. Owls also have multiple vertebrae, the small bones that make up the neck and spine, helping them achieve a wide range of motion. Let’s start learning more interesting facts and basic principles of animals.

Learning Objectives

After completing the topic, the student will be able to:

  • Understand the basic principles of animals like metabolism, bioenergetics and homeostasis.
  • Analyze how an organism is characterized by having different levels of organization built around the cell.
  • List and describe the four major types of tissues found in animals.
  • Examine how specialization of cells in tissues enhances tissue function.
  • Define and distinguish cells, tissues, organs and organ systems.
  • List and analyze the major life processes carried out by each organ system in vertebrate animals.
  • Identify why a disease that damages connective tissue is likely to threaten most of the body’s organs.
  • Recognize how muscle and nervous tissue are interdependent.
  • Define homeostasis, and explain why it is an essential feature of all living organisms.
  • Define, thermoregulation and analyze how animals maintain an internal temperature within a tolerable range.
Maintaining their body temperature is the one of basic principles of animals. Maintaining their body temperature is the one of basic principles of animals. Animals despite their varying evolutionary histories and varying complexity must solve the general challenges of life in obtaining food, oxygen, nourishing themselves, excreting waste products, and their movement from place to place.
Basic Principles

Animals inhabit almost every part of the biosphere. Despite their great diversity, all animals must solve a common set of problems. All animals must obtain oxygen, nourish themselves, excrete waste products, and move. Animals of diverse evolutionary histories and varying complexity must solve these general challenges of life.

Basic concepts such as Form and Function; Organs and Organ systems; Metabolism–a set of chemical reactions to harvest and use energy; Bioenergetics –how organisms obtain, process, and use their energy resources; Homeostasis –steady state or internal balance, helps us to understand the common principles which underlie various life processes.

Anatomy is the study of the structure of an organism and Physiology is the study of the functions an organism performs. Natural selection can fit structure to function by selecting, over many generations, what works best among the available variations in a population.

Form and function: Physical laws and the environment constrain animal size and shape. An animal’s size and shape, features that biologists often call "body plans" or "designs" are fundamental aspects of form and function that significantly affect the way an animal interacts with its environment. By using the terms plan and design here, we do not mean to imply that animal body forms are products of conscious invention. The body plan of an animal results from a pattern of development programmed by the genome, which is the product of millions of years of evolution. The possibilities are not infinite as physical laws and the need to exchange materials with the environment place certain limits on the range of animal forms.

Laws of hydrodynamics help aquatic animals to swim Laws of hydrodynamics help aquatic animals to swim Aquatic mammals such as fishes, dolphins, seals, and whales have evolved with streamlined body (a fusiform shape, which means body tapered on both ends) form that speeds up their swimming in deep waters.
Physical Laws and Animal Form

Physical requirements constrain what natural selection can "invent", including the size and shape of an animal. The size and shape of a mythical dragon can’t generate enough lift with its wings to get off the ground. The laws of hydrodynamics constrain the shapes that are possible for aquatic animals that swim very fast.

Water is about a thousand times denser than air and hence any bump on the body surface that causes drag would impede a swimmer even more than it would a runner or a flyer.

Tuna and other fast ray–finned fishes can swim at speeds up to 80 km/hr. Sharks, penguins, and aquatic mammals such as dolphins, seals, and whales are also fast swimmers. These animals all have the same streamlined body form: a fusiform shape, which means tapered on both ends.

The fact that these speedy swimmers have similar shapes is an example of convergent evolution. Convergence occurs because natural selection shapes similar adaptations when diverse organisms face the same environmental challenge, such as the resistance of water to fast travel.

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