Animal Kingdom Overview

General Concepts

• Animal Definition: Animal = non-human animal. All members of the animal kingdom.
• Animal Characteristics: Multicellular eukaryotes (lack cell walls), heterotrophs, motile, sexual or asexual reproduction, have nerves and muscles.
• Animal Diversity: Diverse species, diverse habitats, diverse characteristics.
• Animal Origins: Common ancestor for all animals is a colonial flagellated protist in Precambrian. Similarity to modern colonial flagellated species and morphological/molecular evidence support this.
• Animal Classification: (not detailed in the provided text)

Animal Characteristics

• Multicellular Eukaryotes: Animals are made of many cells and their cells have a nucleus.
• Heterotrophs: Animals get their energy by consuming other organisms.
• Motile: Animals can move around.
• Sexual or Asexual Reproduction: Animals can reproduce sexually or asexually.
• Nerves and Muscles: Animals have nerves and muscles to help with movement and response to stimuli.

Animal Diversity

• Diverse Species: Animals come in many different species.
• Diverse Habitats: Animals live in many different habitats.
• Diverse Characteristics: Animals have many different characteristics distinguishing them from each other.

Animal Origins

• Common Ancestor: All animals share a common ancestor.
• Precambrian: The ancestor existed in the Precambrian period.
• Evidence: Evidence for this comes from similarities to modern colonial flagellated species and morphological/molecular evidence.

Tissue Stability in Animals

• Plant vs. Animal Cells: Animal cells do not have a cell wall, unlike plant cells which give them rigidity.
• Achieving Stability: Animal tissues gain stability through extracellular junctions which maintain cell shape, structure and function.
• Types of Junctions:
• Anchoring Junctions: Connect proteins to join cells together.
• Tight Junctions: Prevent passing things through cells, holding cells close together.
• Gap Junctions: Enable cell-cell communication and ion exchange between cells.

Animal Body Plans

• Embryonic development pattern: Influences animal body plans
• Germ cell layers: Influences animal body plans
• Body symmetry: Influences animal body plans
• Body cavity type: Influences animal body plans

Sexual Reproduction

• Process: Germ line cells undergo meiosis to produce haploid gametes; gametes fuse (fertilization) to form a diploid zygote.

Asexual Reproduction

• Examples: Budding in hydra, fragmentation in echinoderms, parthenogenesis in insects.
• Protostomes: Spiral cleavage; each cell's developmental path fixed as it's produced; each blastomere cannot become a complete organism by itself.
• Deuterostomes: Radial cleavage; each cell can become a complete organism; developmental path not predetermined.

Germ Layers

• Diploblastic: Two germ layers (ectoderm, endoderm).
• Triploblastic: Three germ layers (ectoderm, endoderm, mesoderm).
• Mesoderm: Forms muscles, skeleton, and structures between gut and external covering.
• Ectoderm: Forms external covering (skin) and nervous system.
• Endoderm: Forms gut lining and digestive tract,

Embryonic Development Differences

• Protostomes: Spiral cleavage.
• Deuterostomes: Radial cleavage.
• Coelom: A body cavity separating the gut from body wall. Fluids fill body cavities.
• Acoelomate: No body cavity.
• Pseudocoelomate: Fluid-filled space between endoderm and mesoderm.

Homeostasis

• Definition: Maintaining the body's internal environment near a stable level.
• Methods: Negative feedback loops, positive feedback loops, feedforward.
• Negative feedback: Counteracts deviations from the set point.
• Positive feedback: Amplifies deviations from the set point.
• Feedforward: Anticipating future needs to adjust physiology in advance.

Thermoregulation

• Endotherms: Obtain heat primarily from internal reactions.
• Ectotherms: Obtain heat primarily from external environment.
• Homeotherms: Maintain constant body temperature.
• Heterotherms: Body temperature varies between self-regulating and being influenced by environment.
• Behavioral Responses: Some animals can regulate temperature through behavioral changes.

Key Terms (From pages 8-14)

• Organ Systems: Groups of organs working together
• Tissue Types: Epithelial, connective, muscle, nerve
• Neuron Types: Afferent, efferent, interneurons
• Glial Cells: Support and insulate neurons (e.g., astrocytes, Schwann cells).
• Hypothalamus: Body's 'thermostat'.
• Temperature regulation: Maintaining body temp at optimal levels.
• Torpor: Decrease in body temp for conservation of energy.
• Acclimatization: Changes in the body related to temperature tolerance.

Animal Body Organization & Nervous System

• Layers of Organization: Cells, tissues, organs, organ systems.
• Tissue Types: Epithelial, connective, muscle, nervous
• Neuron Structure: Dendrites, axons.

Tissue Types (from page 11)

• Epithelial Tissue: Sheetlike layers covering body surface and internal organs.
• Connective Tissue: Consists of cell networks, supports other tissues, and transmits mechanical forces.

Connective Tissue

• Types: Loose connective tissue (supports, elasticity, diffusion), cartilage (support, flexibility, movement), adipose tissue (energy reserves, insulation), fibrous connective tissue (strength), bone (movement, support); blood (substance transport)