Lecture 1 Introduction to Animal Biology

Instructor: C. Isabelle Aubé (she/her)Email: isabelle.aube@dal.ca

Important Concepts in Animal Biology

Introduction

Animal biology explores the structure, function, and behavior of animals, emphasizing how these elements interact with environmental factors.

Five Core Concepts

1. Structure & Function: Investigates how the physical characteristics of animals influence their operations and interactions with their environment.

2. Evolution: Details how organisms adapt to their environments through natural selection, shaping their physiological and morphological traits over time for improved survival and reproduction. Fittnes to next gen

3. Systems: Focuses on how various biological structures collaborate to form complex systems that perform specific functions within organisms.

4. Information Flow: Examines the communication mechanisms within biological systems, emphasizing the role of signaling and genetic information in development and functioning. Electrical

5. Transformations of Energy and Matter: Describes the processes through which animals acquire, transform, and utilize energy and matter for their survival, including metabolic pathways and nutritional needs.

Definition of an Animal

An animal is defined as a multicellular, heterotrophic organism that generally can move at some stage of its life cycle, lacks cell walls, and possesses specialized structures and Hox genes that guide development and body plan. Movement

Essential Functions of Animal

Overview of key physiological functions vital for survival includes:

• Reproduction and Development: The processes by which animals produce offspring and undergo development stages.

• Matter and Energy Transport: Systems comprising circulatory and respiratory functions that transport nutrients and gases throughout the organism.

• Gas Exchange: Essential for delivering oxygen and removing carbon dioxide, facilitated through structures like lungs or gills.

• Defense Against Pathogens. Protection: Immune responses that protect against infections and diseases.

• Water and solute concentration: Maintaining homeostasis: Mechanisms that regulate internal conditions to ensure optimal functioning of cells and systems. Homeostasis Maintenance: Mechanisms that regulate internal conditions to remain stable despite external fluctuations. (parece que son 1 solo)

• Support and Movement: Structures like skeletons and muscles facilitate locomotion and structural integrity.

• Coordination of Body Functions: Integration among various organ systems for optimal functionality and coherence of physiological processes.

Hierarchical Organization in Biology

Levels of Biological Organization:

• Molecules (proteinas, amino acidos, sugars, lipids, etc…)

• Organelles (mitocondria, nucleo)

• Cells

• Tissues (membranes: epithelial, muscle, nervous, connective)

• Organs

• Organ Systems (digestive system, etc…)

• Organisms

  Each level represents an increasing complexity, with emergent properties arising from interactions at higher organizational levels.

Structure-Function Relationship

• Structure Enables Function: The design of a biological structure directly affects its capabilities and efficiencies in performing specific roles.

• Functional Constraints: Specialization of structures may limit their ability to perform other functions, highlighting evolutionary trade-offs. It is impossible to optimize for all parameters.

• Functional Trade-offs: Example: Bone provides strength at the expense of flexibility, while cartilage offers flexibility but is structurally weaker.

Respuesta imagen era B, porque es mas delgado y mas fácil de mover entre membranas.

How is function related to structure?

Evolution and Adaptation

• Natural Selection: Organisms evolve through selective pressures that favor specific traits promoting greater fitness in their environments over generations. Better functional structure/more adapted for each environment.

• Examples: Adaptations seen in species like the Grey Seal (Halichoerus grypus) demonstrate evolution's role in physiological traits and survival tactics.

Biological Interactions: Biological Structures interact to form complex systems.

• Biological structures interconnect to form intricate systems, with the interplay between tissues, organs, and entire systems dictating physiological functions.

• “A change in one component of a network can affect many other components.”

• Emergent Properties: Each level of organization has properties not exhibited by lower levels. Higher levels (like organs) exhibit unique functions not present when examining individual components (e.g., cardiac muscle tissue's ability to contract forms the heart's pumping action).

  La respuesta a la pregunta es A, porque por si sola puede es vida, pero las otras 3 necesitan la ayuda de otras estructuras para hacer esa accion.

Exchange with the Environment

• All cells require material exchange with their surroundings to maintain homeostasis.

• Simple organisms, such as Hydra, can perform direct exchanges with the environment, whereas complex organisms necessitate specialized systems like circulatory and respiratory systems to facilitate efficient exchange.

More complicated bodies require organ systems that: can exchange material with the external environment, can transport material around the body.

Animals have systems that perceive and respond to changes in their internal and external environments

• All perception and response requires information flow (aka communication):

– Chemical and/or electrical signaling between cells coordinates responses at the cellular, tissue, organ, and system levels.

• Endocrine and nervous systems are the major systems that control responses to stimuli and coordinate body activities.

Homeostasis

• Definition: The ability to maintain stable internal conditions despite varying external environments.

• Importance: Essential for the optimal functioning of cells and enzymatic reactions necessary for life. Enzymes and membranes are sensitive to changes in their surroundings.

Mechanisms:

• Negative Feedback: Is a control mechanism in which the responde opposes the original stimulus. Produces an effect that counteracts the original stimulus, helping to stabilize the system.

• Positive Feedback: Is a control mechanism in which the responde reinforces the original stimulus. Amplifies the initial stimulus leading to an enhanced response (e.g., during childbirth).

Respuesta a la pregunta es: todas menos C.

Regulated changes in physiological parameter set point (and their normal ranges) are essential to normal body functions.

• Stage of life (eg. puberty)

• Cyclic (eg. menstrual cycles, circadian rhythm)

• Responde to environmental change (eg. acclimatization)

Energy Requirement and Resource Trade-offs

• Animals derive energy from food sources, converting nutrients into ATP for cellular processes. Chemical energy is converted to ATP.

• Limited energy and material resources: requires efficient allocation across competing functional demands.

• Resource Trade-offs: The necessity of balancing energy allocation among competing physiological functions results in adaptations, such as the skin's protective qualities limiting material exchange with the environment.

Respuesta a la pregunta TODOS A es fucntional trade off, B es life history trade off, C resource trade off.

Summary Points

• Animals are recognized as multicellular, heterotrophic organisms that lack cell walls and possess Hox genes.

• Core activities common to animals involve reproduction, energy transport, gas exchange, environmental interaction, and homeostasis maintenance.

• The relationship between structure and function underlines physiological mechanisms essential for animal survival.

• Homeostasis is sustained through feedback mechanisms, with energy derived from various resources often leading to functional trade-offs.

Homework Practice Questions

1. True or False: All animals can move at some point in their lives.

2. What is the term for maintaining a stable internal environment?A. Acclimation B. Homeostasis C. Trade-off D. Negative feedback

3. Identify a connective tissue from the following:A. Skin B. Nerves C. Blood D. Cuboidal epithelium E. Smooth muscles

4. Explain how fusiform shape enhances swimming in aquatic animals.

5. Which of the following are energetic trade-offs?A. Skin structure and material exchange B. Lung structure and gas exchange surface area C. Suppression of immune function during reproduction D. A and B E. A and C

6. Differentiate between positive and negative feedback mechanisms.

Next Lecture

Topic: Animal Development (Ch. 47.1, 47.2)