Lab Exam - Midterm

Key Terms & Definitions

• Tissue: A group of similar cells that work together to perform a specific function.

• Vertebrate: An animal with a backbone, such as mammals, birds, reptiles, amphibians, and fish.

• Invertebrate: An animal without a backbone, including insects, mollusks, and cnidarians.

Types of Animal Skeletons

• Hydrostatic Skeleton: A flexible, fluid-filled internal cavity that provides structure and support (e.g., jellyfish, earthworms).

• Exoskeleton: A hard, external structure that supports and protects an animal’s body (e.g., insects, crustaceans).

• Endoskeleton: An internal skeleton made of bone or cartilage (e.g., humans, birds, reptiles).

Bone Tissue

• Elements that Give Bone Strength: Calcium, phosphorus, and collagen.

• Canal in Bone & Its Purpose: The Haversian canal, which carries blood vessels and nerves to nourish bone cells.

Muscle Tissue

• Voluntary Muscle Tissue: Skeletal muscle, responsible for movement.

• Other Two Muscle Types: Cardiac muscle (heart) and smooth muscle (organs, blood vessels).

• General Purpose of Muscle Tissue: To contract and generate movement, using actin and myosin proteins.

Nervous Tissue

• General Purpose: To transmit electrical and chemical signals throughout the body.

• Sensory vs. Motor Neurons: Sensory neurons detect stimuli and send signals to the brain, while motor neurons send signals from the brain to muscles.

Animal Bones

• Why Birds Have a Keeled Sternum: Provides an attachment point for powerful flight muscles.

• How Teeth Relate to Diet: Carnivores have sharp teeth for tearing meat, while herbivores have flat teeth for grinding plants.

• What Bones Tell Us About Fossilized Animals:

  • Bone structure can indicate how an animal moved (e.g., bipedal vs. quadrupedal).

  • Bone size and density can suggest environmental adaptations (e.g., aquatic vs. land animals).

Scientific Method

• Steps: Observation → Hypothesis → Experiment → Data Collection → Analysis → Conclusion.

• Observation: Gathering information using the senses.

• Hypothesis: A testable explanation for an observation.

• Quantitative vs. Qualitative Observations:

  • Quantitative: Measured with numbers (e.g., height, weight).

  • Qualitative: Descriptive observations (e.g., color, texture).

• Independent vs. Dependent Variables:

  • Independent Variable: What is changed in an experiment.

  • Dependent Variable: What is measured.

• Controlled Variables (Controls): Factors that remain constant to ensure valid results.

Protists & Protozoans

• Definitions:

  • Protist: A diverse group of eukaryotic organisms, often unicellular.

  • Protozoan: A single-celled, animal-like protist.

  • Eukaryote: Organism with a nucleus and membrane-bound organelles.

  • Plankton: Small aquatic organisms that drift in water.

• Identifications:

  • Paramecium: Moves via cilia; obtains food through an oral groove.

  • Euglena:

    • Stigma (Eyespot): Detects light for photosynthesis.

    • Energy Source: Can use photosynthesis or consume food.

    • Movement: Moves using a flagellum.

  • Dinoflagellates: Cause red tide, a harmful algal bloom.

  • Diatoms: Important for global oxygen production and marine food chains.

• Key Terms:

  • Fission: Asexual reproduction by cell division.

  • Plankton: Microscopic drifting organisms in water.

Flatworms & Rotifers

• Definitions:

  • Definitive Host: The organism in which a parasite reaches adulthood.

  • Intermediate Host: A host where the parasite develops but doesn’t reach adulthood.

  • Parthenogenesis: Asexual reproduction without fertilization.

  • Turbellarian: A free-living flatworm.

  • Monoecious: Having both male and female reproductive organs.

• Flatworm Identifications:

  • Planaria:

    • Ocelli: Light-sensitive eyespots.

    • Pharynx: Used for feeding.

    • Gastrovascular Cavity: Digests food.

  • Clonorchis (Fluke):

    • Structures: Uterus, sucker (for attachment).

    • Hosts: Snail (intermediate), fish (intermediate), human (definitive).

  • Tapeworm:

    • Structures: Scolex (head), proglottid (body segments), uterus.

    • Energy Source: Absorbs nutrients through its skin.

    • Other Hosts: Livestock (cows, pigs, fish).

• Rotifer Identifications:

  • Corona: Crown-like cilia for movement and feeding.

  • Cilia: Hair-like structures for movement.

  • Mastax: Grinds food.

  • Toe: Helps attach to surfaces.

  • Feeding: Uses cilia to draw in food particles.

Cnidarians

• Identifications:

  • Hydra (Hydrozoa):

    • Structures: Tentacle, basal disc, gastrovascular cavity, hypostome.

    • Reproduction: Asexual (budding) and sexual.

  • Obelia (Hydrozoa):

    • Polyp Stage Structures: Gonangium (reproduction), hydranth (feeding).

    • Stages: Polyp (attached), Medusa (free-swimming).

  • Aurelia (Moon Jelly, Scyphozoa):

    • Structures: Radial/ring canals (nutrient transport), oral arms (feeding), gonads (reproduction), tentacles (stinging), mesoglea (jelly-like layer), mouth.

• Key Terms:

  • Nematocyst: Stinging structure in cnidocytes.

  • Mesoglea: Gelatinous layer in jellyfish.

  • Hydrostatic Skeleton: Fluid-filled internal support.

  • Colonial/Modular Organism: Organisms made of repeating units (e.g., corals, Obelia).

• Polyp vs. Medusa:

  • Polyp: Sessile, asexual reproduction.

  • Medusa: Free-swimming, sexual reproduction.

Worms

• Ascaris: Males are smaller and have a curved tail; females are larger and straight.

• Earthworm External Structures:

  • Setae: Bristle-like hairs for movement.

  • Clitellum: Secretes mucus for reproduction.

  • Metamere (Segment): Body segments.

  • Prostomium: First segment, aids in burrowing.

• Earthworm Internal Structures:

  • Intestine: Digests food.

  • Crop: Stores food.

  • Gizzard: Grinds food.

  • Seminal Vesicles: Store sperm.

  • Hearts: Pump blood.

  • Septum: Separates segments.

• Key Terms:

  • Peristalsis: Muscle contractions for movement.

  • Deposit Feeder: Eats organic material in soil.

  • Castings: Nutrient-rich worm waste.

  • Sexual Dimorphism: Males and females have different appearances.

  • Complete vs. Incomplete Gut: Complete has two openings (mouth/anus); incomplete has one.

  • Closed Circulatory System: Blood remains in vessels.