Biology Exam 3 Review

Producers

• Organisms that synthesize their own food and serve as the foundation for the food chain.

• Types:

• Micro producers: e.g., algae, cyanobacteria (mostly aquatic)

• Macro producers: e.g., plants (mostly terrestrial)

Types of Autotrophs

• Photoautotroph: Uses sunlight to create organic compounds.

• Chemoautotroph: Utilizes chemical energy for organic compounds.

• Phytoplankton: Free-floating plant-like organisms in water.

• Red tide: Occurs from dinoflagellate blooms, which can produce toxins.

Major Groups of Micro Producers

• Diatoms:

• Characteristics: Glass-like shell, belong to phytoplankton.

• Dinoflagellates:

• Characteristics: Have flagella, are phytoplankton, produce toxins, and cause red tides.

• Phytoplankton: General term for plant-like drifters.

Algal Symbiosis

• Mutualistic relationships between algae and:

• Corals

• Fungi (lichens)

Algal Blooms and Dead Zones

• Cause: Human fertilizer runoff, warming temperatures.

• Effect: Algal blooms die, decompose, depleting oxygen and leading to dead zones.

Categories of Early Plants

• Mosses (Bryophytes):

• Nonvascular, small, must live near water to reproduce (no pollen/seeds).

• Ferns (Seedless Vascular Plants):

• Have vascular tissue but no pollen/seeds, also require proximity to water for reproduction.

Categories of Seeded Plants

• Gymnosperms:

• Examples: Conifers, produce seeds/pollen (wind-carried).

• Angiosperms:

• Examples: Flowering plants, produce seeds/pollen (animal-carried), develop fruit from pollinated flowers.

Key Plant Structures

• Peat: Partially decayed mosses, useful in fuel and bedding, retains material.

• Xylem: Conducts water/minerals.

• Phloem: Food conducting.

• Meristems: Growth and differentiation sites.

• Alternation of Generations: Plants alternate between haploid and diploid stages.

Plant Modifications

• Roots:

• Storage (e.g., sweet potatoes), pneumatophores (for oxygen), strangling roots (parasitic), stabilizing roots (buttress, prop).

• Stems:

• Storage (e.g., potatoes), asexual reproduction (stolons/runners), protection (thorns).

• Leaves:

• Storage (bulbs like onions), grasping (tendrils), protection (spines on cacti).

Buds

• Apical and Axillary Buds: Contain meristems that lead to elongation or branching for flowers/branches.

Plant Growth Types

• Primary Growth: Increases length, driven by apical meristem.

• Secondary Growth: Increases girth, driven by lateral meristems (vascular/cork cambium).

Parasitic vs. Carnivorous Plants

• Parasitic Plants: Siphon nutrients from other organisms.

• Carnivorous Plants: Obtain nutrients from consuming insects in nutrient-poor soils.

Crop Rotation

• Definition: Growing different crops yearly or leaving land fallow to recover.

• Importance: Prevents nutrient depletion and reduces the need for excessive fertilizers.

Types of Heterotrophs

• Common Types:

• Detritivores: Feed on decayed material (e.g., earthworms).

• Filter Feeders: Consume dissolved organic matter in water.

Invertebrate Groups

• Porifera:

• Characteristics: Asymmetrical, no tissues, reproduce sexually and asexually, filter feeders.

• Cnidaria:

• Examples: Jellyfish, corals; characteristics include a nerve net and radial symmetry.

• Platyhelminthes (Flatworms):

• Types: Flukes (parasitic) and tapeworms (segments with gonads).

Nematodes and Molluscs

• Nematodes: Roundworms with a complete circulatory system; some parasitic.

• Molluscs: Generally aquatic, often have shells, diverse forms (e.g., snails, clams, squid).

Annelids

• Known as segmented worms, include leeches and earthworms.

Arthropods

• Characteristics: Jointed appendages, exoskeleton, open circulatory system.

• Groups:

• Insects: Three pairs of legs, four body segments.

• Arachnids: Four pairs of legs, two body segments, silk glands.

• Crustaceans: Variable body segments and legs, mostly aquatic.

Symmetry Types

• Bilateral Symmetry: Anatomical directions with two equal halves.

• Radial Symmetry: Body parts arranged around a central axis.

Body Cavity

• Function: Compartmentalizes organs for specialization, cushioning, and independent movement.

Vertebrate Groups

• Fish:

• Types:

  • Chondrichthyes: Cartilaginous fishes, e.g., sharks, rays (internal fertilization, ovoviviparous).

  • Osteichthyians: Bony fish, oviparous, have swim bladders, external fertilization.

• Amphibians:

• Characteristics: Larvae aquatic with gills, adults terrestrial with lungs, gelatinous eggs (mostly external fertilization).

• Reptiles:

• Features: 3-chambered heart, leathery-shelled eggs, internally fertilized.

• Birds:

• Classified as reptiles, 4-chambered heart, feathers, endothermic, hard-shelled eggs.

• Mammals:

• Endothermic, live birth, produce milk, have hair, provide extensive care for young.

Reproductive Types

• Oviparous: Eggs laid outside the body.

• Ovoviviparous: Eggs hatch inside the body.

• Viviparous: Live birth.

Amniote Characteristics

• Embryo encased in a watery sack, crucial for reproduction on land.

Thermoregulation

• Endotherm: Regulates body temperature internally.

• Ectotherm: Body temperature regulated by the environment.

Parts of an Egg

• Thick/Thin Albumin: Provides nourishment.

• Yolk: Nutritional source.

• Allantois: Waste disposal.

• Air Sac: Involved in gas exchange.

• Shell: Protective outer layer.

• Amnion: Regulates temperature, cushions the embryo.

• Germinal Disc: Develops into the embryo if fertilized.

• Chalaza: Anchors the yolk.

• Chorion: Develops into the placenta in mammals.