General Biology 2 Review – Final Exam

Kingdom Animalia

• General characteristics of animals include:

  • Multicellularity

  • Heterotrophic metabolism

  • Motility at some life stage

• Hox genes play a critical role in body plan development.

Evolutionary History

• Evolution of multicellularity marked significant steps in animal evolution.

• Cambrian Explosion: A rapid diversification of life forms approximately 541 million years ago.

• Distinction between Vertebrates and Invertebrates:

  • Vertebrates possess a backbone; Invertebrates do not.

Major Concepts

Metazoa

• Organized into levels:

  • Cellular

  • Tissue

  • Organ

  • System

Body Plans

• Symmetry Types:

  • Radial Symmetry: Organisms can be divided into similar halves by any longitudinal plane.

  • Bilateral Symmetry: Only one longitudinal plane divides the organism into two mirror-image halves.

• Importance of features:

  • Cephalization: Concentration of sensory organs at the head end of an organism.

  • Body cavities: Coelom types - Acoelomate (no coelom), Pseudocoelomate (false coelom), Eucoelomate (true coelom).

Developmental Patterns

• Diploblastic vs. Triploblastic:

  • Diploblastic: Two germ layers (ectoderm and endoderm).

  • Triploblastic: Three germ layers (ectoderm, mesoderm, endoderm).

• Early Development:

  • Protostome vs. Deuterostome development patterns.

Phylogenetic Tree of Animals

• Understanding phylogeny is crucial for classifying animals based on their evolutionary relationships.

Invertebrate Phyla

Porifera (Sponges)

• Simple cellular organization (ostia, osculum, mesohyl).

• Reproduction methods: Sexual and Asexual (e.g., gemmules).

Cnidaria

• Features:

  • Radial symmetry

  • Diploblastic tissues

  • Types: Polyp and Medusa forms

• Unique structures: Cnidocytes with nematocysts.

• Key Classes:

  • Scyphozoa: Jellyfish life cycle.

  • Hydrozoa: E.g., Obelia.

  • Anthozoa: E.g., Corals and Sea Anemones.

Lophotrochozoa

• Platyhelminthes (Flatworms)

  • Features include: bilateral symmetry, triploblastic, acoelomate.

  • Classifications like Turbellarians (Planaria) and Cestodes (Tapeworms).

• Annelida (Segregated worms)

  • Metamerism and closed circulatory system.

  • Examples include Earthworms and Leeches.

• Mollusca

  • Three main parts: Head-foot, Visceral mass, Mantle.

  • Groups: Gastropods, Bivalves, Cephalopods.

Ecdysozoa

• Characteristics include ecdysis (molting).

• Notable Phylum: Nematoda (Roundworms) and Arthropoda (Insects and Crustaceans).

Deuterostomes

• Key Characteristics:

  • Radial symmetry

  • Indeterminate cleavage

• Major Groups:

  • Echinodermata: Starfish, sea urchins.

  • Chordata: Features include Notochord, Dorsal hollow nerve cord.

Vertebrates

• Characteristics:

  • Backbone, endoskeleton, complex organ systems.

  • Subdivided into:

  • Jawless fishes (Cyclostomata): E.g., Lampreys.

  • Jawed vertebrates (Gnathostomes): Include Cartilaginous and Bony fishes.

Tetrapods

• Evolve features to adapt to terrestrial life:

  • Limbs, lungs, higher metabolic functions.

• Major Classes:

  • Amphibia: Frogs, toads (moist skin, external fertilization).

  • Reptilia: Evolution from amphibians.

  • Aves: Birds with features like feathers, hollow bones.

  • Mammalia: Higher brain functions, live birth (in most).

Adaptive Features

• Endotherms vs. Ectotherms: Adaptation strategies for regulating body temperature.

• Importance of adaptations across evolutionary history influencing survival and reproduction.

Review and Practice Questions

• Focus on evolutionary theory, classifications, and the importance of animal traits for survival and adaptation.

• Essential to understand the ecological impact of biodiversity and species interaction in ecosystems.

Darwin and Evolution

• Species and Populations: Focus on the diversity of life forms.

• Natural Selection and Adaptation: The process through which species evolve, emphasizing variations and the concept of "survival of the fittest".

• Homologous vs. Analogous Structures: Understanding the distinction in the context of evolutionary processes.

• Evolution in a Genetic Context:

  • Microevolution: Changes within species over generations.

  • Key terms include: Gene, allele, genotype, and phenotype.

  • Allelic Frequencies: Proportions of different alleles in a population.

  • Genotypic Frequencies: Proportions of different genotypes in a population.

  • Hardy-Weinberg Principle: No mutations, no gene flow, random mating, no genetic drift, and no selection lead to a stable allelic frequency.

  • Causes of Microevolution: Genetic mutations, gene flow, nonrandom mating, genetic drift, bottleneck effect, and founder effect.

Classification of Living Things

• Domains:

  • Bacteria

  • Archaea

  • Eukarya

Viruses

• Characteristics: Obligate intracellular parasites; questions around if they are alive; infectious properties.

• Structure: Consists of a covering (capsid, envelope) and an inner core (nucleic acid, proteins).

Prokaryotes: Bacteria and Archaea

• Structure: Includes cell envelope, cytoplasm, appendages, plasmids, and endospores.

Protists

• Characteristics: Eukaryotic, unicellular, and paraphyletic groups.

• Importance: Ecological roles, health impacts, and economic significance; interactions such as symbiosis and parasitism.

Fungi

• Characteristics: Eukaryotic heterotrophs that absorb nutrients, acting as saprotrophic decomposers.

• Structure and Components: Mycelium, hyphae, chitin, glycogen.

• Reproduction:

  • Sexual Reproduction: Involves haploid hyphae, dikaryotic stages, diploid zygotes, and spores.

  • Asexual Reproduction: Includes budding, fragmentation, and spores.

Plants

• Characteristics: Multicellular photosynthetic eukaryotes with a cellulose cell wall.

• Life Cycle: Involved in alternation of generations: sporophyte, gametophyte, spore, zygote, and gamete.