Comprehensive Study Guide: Plant and Animal Structure, Function, and Ecology

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Plant Structure and Growth

Root and Shoot Systems

The root system anchors the plant and absorbs water and minerals, while the shoot system consists of stems, leaves, and reproductive structures, supporting photosynthesis and reproduction.

Root System: Underground, absorbs water/minerals, stores carbohydrates.
Shoot System: Above ground, includes stems (support, transport), leaves (photosynthesis), and flowers (reproduction).

Plant Tissue Types

Dermal Tissue: Protective outer covering (epidermis, periderm in woody plants).
Vascular Tissue: Conducts water, minerals, and sugars (xylem and phloem).
Ground Tissue: Functions in photosynthesis, storage, and support (parenchyma, collenchyma, sclerenchyma).

Meristems and Plant Growth

Apical Meristems: Located at tips of roots and shoots; responsible for primary growth (lengthening).
Lateral Meristems: Vascular cambium and cork cambium; responsible for secondary growth (thickening).

Primary vs. Secondary Growth

Primary Growth: Increases length; occurs at apical meristems.
Secondary Growth: Increases girth; occurs in woody plants via lateral meristems.

Stem and Leaf Anatomy

Stem: Epidermis, cortex, vascular bundles (xylem inside, phloem outside), pith.
Leaf: Upper/lower epidermis, mesophyll (palisade and spongy), veins (vascular bundles), stomata.

Transport in Plants

Water Transport

Water moves from roots to leaves via the xylem, driven by transpiration and cohesion-tension mechanism.

Transpiration: Evaporation of water from leaves pulls water upward.
Cohesion-Tension: Water molecules stick together (cohesion) and to xylem walls (adhesion).

Sugar Transport

Sugars are transported from sources (leaves) to sinks (roots, fruits) via phloem by pressure-flow mechanism.

Source: Site of sugar production (usually leaves).
Sink: Site of sugar use/storage (roots, fruits).

Adaptations for Resource Acquisition

Root hairs, mycorrhizae, leaf modifications, and vascular tissue specialization enhance resource uptake.

Mutualistic Relationships

Plants & Fungi: Mycorrhizal associations increase nutrient uptake.
Plants & Bacteria: Nitrogen-fixing bacteria (e.g., Rhizobium) provide usable nitrogen.

Photosynthesis and Cellular Respiration

Relationship and Overview

Photosynthesis: Converts light energy to chemical energy; occurs in chloroplasts.
Cellular Respiration: Releases energy from glucose; occurs in mitochondria.
These processes are complementary: products of one are reactants of the other.

Overall Reactions

Photosynthesis:
Cellular Respiration:

Stages and Locations

Photosynthesis: Light reactions (thylakoid membrane), Calvin cycle (stroma).
Respiration: Glycolysis (cytoplasm), Krebs cycle (mitochondrial matrix), ETC (inner mitochondrial membrane).

Absorption/Action Spectrum

Absorption Spectrum: Wavelengths of light absorbed by pigments (chlorophyll a, b, carotenoids).
Action Spectrum: Wavelengths most effective for photosynthesis.

Plant Reproduction

Flower, Seed, and Fruit Structure

Flower: Sepals, petals, stamens (anther, filament), carpels (stigma, style, ovary).
Seed: Embryo, endosperm, seed coat.
Fruit: Mature ovary, aids in seed dispersal.

Double Fertilization in Angiosperms

One sperm fertilizes egg (zygote); another fuses with two polar nuclei (endosperm).

Pollination and Coevolution

Pollinators: Wind, water, animals (insects, birds, bats).
Coevolution: Adaptations in plants and pollinators enhance mutual success.

Plant Hormones and Responses

Major Plant Hormones

Auxins: Cell elongation, apical dominance.
Gibberellins: Stem elongation, seed germination.
Cytokinins: Cell division, delay aging.
Abscisic Acid (ABA): Inhibits growth, closes stomata.
Ethylene: Fruit ripening, leaf abscission.

Plant Responses to Stimuli

Phototropism: Growth toward light.
Gravitropism: Growth in response to gravity.
Thigmotropism: Response to touch (e.g., tendrils).

Animal Structure and Function

Animal Tissue Types

Epithelial: Covers surfaces (skin, lining of gut).
Connective: Supports, binds (bone, blood, fat).
Muscle: Movement (skeletal, cardiac, smooth).
Nervous: Transmits signals (neurons, glia).

Homeostasis and Feedback

Homeostasis: Maintenance of stable internal environment.
Negative Feedback: Reduces change (e.g., body temperature regulation).
Positive Feedback: Amplifies change (e.g., childbirth contractions).

Thermoregulation

Endotherms: Regulate body temperature internally (e.g., mammals, birds).
Ectotherms: Rely on external sources (e.g., reptiles, fish).
Factors affecting metabolic rate: size, activity, environment.

Animal Nutrition and Digestion

Dietary Requirements

Essential nutrients: amino acids, fatty acids, vitamins, minerals.

Digestive Compartments and Pathway

Mouth (mechanical/chemical digestion) → Pharynx → Esophagus → Stomach (protein digestion) → Small intestine (enzymatic digestion, absorption) → Large intestine (water absorption) → Rectum → Anus.
Accessory organs: salivary glands, liver, gallbladder, pancreas.

Glucose Homeostasis

Insulin: Lowers blood glucose by promoting uptake/storage.
Glucagon: Raises blood glucose by stimulating release from stores.

Circulation and Gas Exchange

Circulatory System Pathway

Blood flows: Vena cava → Right atrium → Right ventricle → Pulmonary artery → Lungs → Pulmonary vein → Left atrium → Left ventricle → Aorta → Body.
Valves prevent backflow; arteries carry blood away from heart, veins toward heart.

Blood Pressure and Velocity

Highest in arteries, lowest in veins; diseases include hypertension, atherosclerosis.

Respiratory System Pathway

Air: Nasal cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli (site of gas exchange).

Immunity

Innate vs. Adaptive Immunity

Innate: Non-specific, rapid (skin, phagocytes, inflammation).
Adaptive: Specific, slower (B cells—humoral; T cells—cell-mediated).

Immune Disorders

Autoimmune diseases (e.g., lupus), immunodeficiency (e.g., HIV/AIDS), allergies.

Excretion and Osmoregulation

Nitrogenous Wastes

Ammonia: Aquatic animals.
Urea: Mammals, amphibians.
Uric Acid: Birds, reptiles.

Urine Production in Mammals

Blood filtered in kidneys (nephron: glomerulus, tubules) → Ureter → Bladder → Urethra.

Endocrine System

Endocrine Glands and Hormones

Pituitary (growth hormone), thyroid (thyroxine), adrenal (adrenaline), pancreas (insulin, glucagon), gonads (sex hormones).
Hormone effects depend on target cell receptors and signal pathways.

Reproduction and Development

Reproductive Anatomy and Cycles

Male: Testes (sperm production), vas deferens, urethra, penis.
Female: Ovaries (egg production), oviducts, uterus, vagina.
Ovarian/Menstrual Cycles: Follicular phase, ovulation, luteal phase, menstruation.

Fertilization and Development

Fertilization → Zygote → Cleavage → Blastula → Gastrula → Organogenesis.

Nervous System

Neuron Structure and Function

Dendrites (input), cell body, axon (output), synaptic terminals.
Types: sensory, interneurons, motor neurons.

Membrane Potentials

Resting Potential: Maintained by Na+/K+ pumps.
Action Potential: Rapid depolarization and repolarization; Na+ influx, K+ efflux.
Depolarization (membrane potential becomes less negative), repolarization (returns to negative), hyperpolarization (more negative than resting).

Myelin and Synapses

Myelin (produced by Schwann cells/oligodendrocytes) increases conduction speed.
Synapses: Electrical and chemical; neurotransmitters (e.g., acetylcholine, dopamine).

Autonomic Nervous System

Sympathetic: "Fight or flight" responses.
Parasympathetic: "Rest and digest" responses.

Brain and Sensory Organs

Major brain structures: cerebrum, cerebellum, brainstem, hypothalamus, etc.
Ear: Outer, middle, inner (cochlea—hearing).
Eye: Cornea, lens, retina, optic nerve; visual pathway to cortex.

Musculoskeletal System

Skeletal Muscle Structure and Function

Muscle fibers contain myofibrils (actin, myosin).
Sliding filament model: Ca2+ enables myosin-actin interaction for contraction.

Types of Skeletons

Hydrostatic: Fluid-filled (e.g., worms).
Exoskeleton: External (e.g., insects).
Endoskeleton: Internal (e.g., vertebrates).

Animal Behavior

Communication and Learning

Communication: Visual, auditory, chemical, tactile signals.
Learning: Habituation, imprinting, associative, social, cognitive.

Behavior and Evolution

Optimal foraging, mating systems, natural selection, altruism (kin selection, reciprocal altruism).

Ecology and Ecosystems

Biotic and Abiotic Factors

Biotic: Living components (plants, animals, microbes).
Abiotic: Non-living (temperature, water, nutrients).

Population Growth Models

Exponential Growth:
Logistic Growth:
Human population growth is currently exponential but may slow due to resource limits.

Species Interactions

Mutualism (+/+), Predation (+/-), Competition (-/-), Commensalism (+/0), Parasitism (+/-).

Food Chains, Webs, and Energy Flow

Energy flows from producers to consumers; only ~10% transferred between trophic levels.

Succession

Primary Succession: Begins on bare substrate (no soil).
Secondary Succession: Follows disturbance where soil remains.

Nutrient Cycling

Energy flows one-way; chemicals (C, N, P) are recycled through biotic and abiotic components.

Plant Hormone	Main Function
Auxin	Cell elongation, apical dominance
Gibberellin	Stem elongation, seed germination
Cytokinin	Cell division, delay aging
Abscisic Acid	Inhibits growth, closes stomata
Ethylene	Fruit ripening, leaf abscission

Animal Tissue Type	Example
Epithelial	Skin, lining of gut
Connective	Bone, blood, fat
Muscle	Skeletal muscle, heart
Nervous	Brain, nerves

Additional info: Some explanations and examples were expanded for clarity and completeness based on standard biology curricula.