Plant and Animal Diversity: Adaptations, Anatomy, and Major Groups

Introduction

This study guide covers the key concepts and terminology required for understanding the diversity, adaptations, and classification of plants and animals. It is designed to help students prepare for exam questions on evolutionary adaptations, comparative anatomy, and the major phyla of the plant and animal kingdoms.

Adaptations and Diversity of Land Plants

Adaptations for Terrestrial Life

• Adaptations for Land: Land plants evolved several adaptations to survive outside aquatic environments, including a waxy cuticle to prevent water loss, stomata for gas exchange, and vascular tissues for transport of water and nutrients.

• Key Characteristics: Each major group of land plants (bryophytes, ferns, gymnosperms, angiosperms) has unique features that allowed them to colonize terrestrial habitats.

• Example: Bryophytes (mosses) lack vascular tissue and are limited to moist environments, while Angiosperms (flowering plants) have seeds and flowers, allowing for greater reproductive success on land.

Comparative Anatomy and Physiology of Plants

Major Plant Groups

• Bryophytes: Non-vascular plants such as mosses, liverworts, and hornworts.

• Seedless Vascular Plants: Include ferns and their relatives; possess vascular tissues but do not produce seeds.

• Gymnosperms: Seed-producing plants like pines and firs; seeds are not enclosed in fruit.

• Angiosperms: Flowering plants; seeds are enclosed within fruits.

Plant Anatomy and Physiology

• Tissues: Dermal, ground, and vascular tissues (xylem and phloem).

• Meristems: Regions of active cell division (apical, lateral, cork cambium).

• Growth: Primary growth increases length; secondary growth increases girth.

• Organs: Roots, stems, leaves; specialized structures such as guard cells and stomata.

Plant Life Cycles and Reproduction

Alternation of Generations

• Definition: Life cycle alternates between multicellular haploid (gametophyte) and diploid (sporophyte) generations.

• Key Terms: Spores, sporangia, gametophyte, antheridia (male), archegonia (female).

• Double Fertilization: Unique to angiosperms; one sperm fertilizes the egg, another fuses with two nuclei to form endosperm.

Major Animal Phyla and Their Characteristics

Classification and Body Plans

• Symmetry: Radial (e.g., cnidarians) vs. bilateral (e.g., most animals).

• Germ Layers: Diploblastic (two layers: ectoderm, endoderm) vs. triploblastic (three layers: ectoderm, mesoderm, endoderm).

• Body Cavities: Acoelomate (no cavity), pseudocoelomate (partial cavity), coelomate (true cavity).

• Development: Protostomes (mouth develops first) vs. deuterostomes (anus develops first).

• Segmentation: Repeated body segments (e.g., annelids, arthropods).

Major Animal Groups

• Porifera: Sponges; filter feeders with specialized cells (choanocytes).

• Cnidaria: Jellyfish, corals; have gastrovascular cavity, polyp and medusa forms, stinging cells (cnidocytes).

• Platyhelminthes: Flatworms; simple bilateral symmetry, no body cavity.

• Mollusca: Includes bivalves, gastropods, cephalopods; features include muscular foot, mantle, radula.

• Annelida: Segmented worms; true coelom, closed circulatory system.

• Arthropoda: Insects, spiders, crustaceans; exoskeleton, jointed appendages, segmentation.

• Echinodermata: Sea stars, sea urchins; radial symmetry as adults, water vascular system.

• Chordata: Animals with notochord, dorsal hollow nerve cord, pharyngeal slits, post-anal tail.

Key Terms and Definitions

• Monocot vs. Dicot: Monocots have one seed leaf, parallel veins; dicots have two seed leaves, net-like veins.

• Vascular Tissues: Xylem transports water/minerals; phloem transports sugars.

• Mycorrhizae: Symbiotic association between fungi and plant roots.

• Chitin: Structural polysaccharide in fungal cell walls and arthropod exoskeletons.

• Plasmogamy/Karyogamy: Stages in fungal sexual reproduction (fusion of cytoplasm/nuclei).

Comparative Table: Major Animal Phyla

Formulas and Equations

• Surface Area to Volume Ratio: Important for understanding limitations on cell and organism size.

Summary

• Understand the evolutionary adaptations that allowed plants and animals to diversify on land.

• Be able to compare and contrast the anatomy and physiology of major plant and animal groups.

• Know definitions and examples of key biological terms and concepts.

• Be familiar with the distinguishing features of major phyla in the plant and animal kingdoms.