Animal Form and Function

• Animal form and function are correlated at all levels of organization

Learning Goals

• Explain the relationship between animal form and function, address problems arising from increased organism size.
• Differentiate the four main animal tissue types: connective, epithelial, muscle, and nervous.
• Overview each tissue type's main tasks, with tissue type/examples.
• Discuss organism's internal temperature regulation; differentiate endothermic and exothermic organisms.
• Discuss how homeostasis is maintained, examine positive and negative feedback loops and their common occurrences.
• Discuss the relationship between animal size and metabolic rate, and metabolic rate and activity levels.

Animal form and function

• Animals must obtain nutrients and oxygen to survive and produce offspring.
• Anatomy, or biological structure, varies substantially among animals.
• Structure and function correlation means anatomy examination provides clues to physiology, or biological function.
• Size and shape is influential on animal interactions with their environments.
• An animal's body plan is governed by its genome, which is derived from millions of years of evolution.

Evolution of Animal Size and Shape

• Physical laws governing strength, diffusion, movement, and heat exchange constrain animal forms.
• Water's properties restrict possible shapes for fast-swimming animals.
• Convergent evolution often leads to similar adaptations in organisms encountering the same challenges.
• Thicker skeletons become necessary for support of animals as size increases.
• A larger fraction of total body mass consists of muscles needed for locomotion as animals become more massive.
• Mobility is limited at some point due to these challenges.

Exchange with the Environment

• Materials such as nutrients, waste products, and gases must be exchanged across cells' plasma membranes.
• A cell's surface area determines the exchange rate, while the volume determines amount of material exchanged.
• Larger organisms face smaller surface area-to-volume ratios.
• Organisms cannot become excessively large because single cells have sufficient surface area for all necessary exchange.
• Multicellularity works through every cell accessing a suitable aqueous environment.
• Sufficient diffusion is available in thin, multicellular organisms.
• Specialised, branched, or folded structures allows complex organisms sufficient environmental exchange.
• Internal environments that are relatively stable are helpful for complex animals in variable environments.

Hierarchical Organization of Body Plans

• Animal cells organize into tissues, groups of cells with similar appearance and common function.
• Organs are composed from tissues.
• Organ systems come from organs working together.
• Organs like the pancreas are part of more than one organ system.
• Main animal tissue types: epithelial, connective, muscle, and nervous.
• Image from: khanacademy.org

Epithelial Tissue

• Epithelial tissue covers the body's exterior and lines body cavities.
• Cells are packed together tightly
• Epithelial cells can be cuboidal, columnar, or squamous.

Connective Tissue

• In place, connective tissue holds together a number of tissues as well as organs.
• Sparse cells sit within an extracellular matrix.
• Fibers make up the matrix in a solid, liquid, or jell-like foundation.

Connective Tissue Components

• Fibroblasts secrete fiber proteins.
• Macrophages engulf foreign particles and cell debris through phagocytosis.

Types of Connective Tissue Fiber

• Collagenous fibers provide strength and flexibility.
• Reticular fibers join adjacent connective tissues.
• Elastic fibers can snap back to their original length after being stretched.

Types of Connective Tissue

• Loose connective tissue binds epithelia to underlying tissues and situates organs in place.
• Fibrous connective tissue in tendons attaches muscles to bones.
• Ligaments connect bones at joints.
• Bone forms the mineralized skeleton.
• Adipose tissue, or fat, provides insulation and fuel storage.
• Blood, contains blood cells and cell fragments in blood plasma.
• Cartilage acts as a strong and pliable support material.

Muscle Tissue

• Muscle tissue facilitates most body movement.
• Protein filaments are muscle cells for contraction.
• Actin and myosin makes the muscle contract
• Vertebrate body include Striated muscle, Smooth muscle and Cardiac muscle tissue.
• Skeletal muscle, or striated muscle, is responsible for voluntary movement.
• Involuntary body actions depend on smooth muscle.
• Cardiac muscle facilitates heart contraction.

Nervous Tissue

• Information is received, processed, and transmitted by nervous tissue.
• Neurons, or nerve cells transfer nerve impulses.
• Glial cells, or glia gives support cells

Coordination and Control

• Animals' coordination and control systems are the endocrine and nervous systems.
• Hormones, or signaling molecules, are released by the endocrine system throughout the body.
• Coordinating gradual changes affecting the body are best coordinated by the endocrine system.
• The nervous system works to connect body locations while sending targeted information.
• Directing rapid responses to the environment is suited to the nervous system.
• Both systems maintain a well-functioning, stable internal environment through close coordination.

Feedback Control

• Control internal environment by regulating or conforming to external conditions
• A regulator uses internal mechanisms to control its internal condition despite external changes
• Animals may conform their internal variables to match certain external changes
• Animals may regulate on a environmental variable, while conforming to others.

Homeostasis

• Homeostasis is to maintain a steady state or constant internal environment-regardless of external environment.
• It is a homeostatic control system which the animal to stay at or near a particular value or set point.
• If above or below the set point which is detected by a sensor (stimulus).
• The control center generates an output to trigger a response.
• The response returns the variable to the set point.

Negative and Positive Feedback

• This is a control mechanism that "damps" a stimulus
• Negative feedback is important in animal homeostasis.
• Positive feedback amplifies the stimulus
• Positive feedback helps drive the process to completion
• Ex: the labor contractions during childbirth.

Thermoregulation

• A mechanism that animals regulate their internal temperature range.

Endothermic and Exothermic Animals

• Endothermic animals generate heat through metabolism.
• Endothermic animals can maintain high activity levels at high metabolic cost.
• Ectothermic animals gain heat from external sources.
• Ectothermic animals have is low metabolic overhead, less activity outputs but they can tolerate a wider range of internal temperatures.

Thermoregulation Adaptations

• Insulation: reduces heat flow that is blood flow between body and external environment.
• Circulatory adaptations: alter blood flowing between the body core and skin. Vasodilation: blood flow in skin increases, heat is lost
• Cooling by evaporative heat loss, such as sweating, bathing, panting cools animals.
• Water transforms from liquid to vapor as it removes heat from the animal's body.
• Behavioral responses such as relocation and changes in behavior.
• Adjusting metabolic heat production by thermogenesis which is Metabolic heat production to maintain body temperature
• Non-shivering thermogenesis takes place when the hormone causes the mitochondria increases to metabolic activity.

Bioenergetics

• Defined as the energy flow and transformations in between animals
• They determines and animal's nutritional needs, and has to be a relative animal size, activity, and the their environment
• Heterotrophs such as animals harvest chemical energy from food

Biosynthesis

• Remaining food molecules are processed into synthesis the building blocks that are required for body growth and repair.
• Biosynthesis also involved in the production of gametes and synthesis of storage material

Food and Energy

• Energy-containing molecules from food are usually used to make ATP, which powers cellular work

Metabolic Rate

• It is the sum of all energy an animal by uses in a time and is determined by:
• Amount of oxygen that is consumed or the carbon dioxide produced
• Animal heat loss and waste
• Food consumed

Influences on Metabolic Rate

• Endotherm or ectotherm are important factors in metabolic rate.
• The Age, size, activity, temperature, nutrition are key factors as well.

Animal Size

• Smaller sized animals contains a high metallic rate per gram than larger animals
• Trade-offs shaped the evolution of body plans
• As a body size increases, the exchange larger body fraction tissue is needed for exchange, locomotion, supports.
• Body mass is important for metabolic rate

Animals need to do Thermoregulation

• Adélie penguins needs a basal metabolism, reproduction, as well as thermoregulation
• Deer Mouse contains only basal or standard metabolism to reproduce, but needs activity for growth
• The Ball python needs to have 4-kg female for metabolism and thermoregulation as they grows

Activity and Metabolic Rate

• Activity greatly affects metabolic rate in endotherms and ectotherms
• The maximum metabolic rate an animal can retain is inversely related to the duration of activity
• Extremely active animals can sustain for for a long amount of time if they rest

Torpor and Energy Conservation

• Reduce activity and Metabolism that enables animals to save energy while avoiding conditions that are difficult and dangerous
• Daily Torpor exhibits mammals and other small animals to adapted to feed
• Hibernation shows Animals that needs to adapt to the cold during winters.
• Metabolic rates during hibernation can be 20 times slower for the normal body temperature