Prokaryotes and Protists Overview

Prokaryotes (Bacteria and Archaea)

• Characteristics: Unicellular, lack a nucleus and organelles, reproduce via binary fission, can be autotrophs or heterotrophs (some obtain energy from chemical reactions, others produce food like plants).
• Movement: Often use flagella (long tails) or cilia (tiny hairs).
• Examples: Pathogenic (harmful): Yersinia pestis (plague), Clostridium botulinum (botulism); Beneficial: Cyanobacteria (produce oxygen), many types of bacteria in the human microbiome (important for digestion, immunity, etc).
• Human Microbiome: Bacteria living on and in humans. Examples: E. coli (used to make medicine like insulin), oil-eating bacteria (clean up oil spills), bioluminescent bacteria (camouflage in squids).
• Archaea: Two classifications include halophiles (salt-loving) and thermophiles (heat-loving).

Protists

• Characteristics: Eukaryotic (have a nucleus and organelles), often unicellular, not plants, animals, or fungi.
• Nutrition: Can be autotrophs (producing their own food), heterotrophs (consuming other organisms), or mixotrophs (both).
• Reproduction: Can reproduce asexually or sexually.
• Groups:
  • Protozoa ("animal-like"): Heterotrophic, move using flagella, cilia, or pseudopods (e.g., amoeba). Examples include Giardia (causes giardiasis), Trypanosoma (causes sleeping sickness), and Plasmodium (causes malaria). Brain-eating amoeba is another example - focus on Plasmodium and malaria for exam preparation as requested.
  • Algae ("plant-like"): Photoautotrophs (performing photosynthesis), usually found in water. Examples include diatoms (important producers of oxygen) and dinoflagellates (many are symbiotic).
  • Slime molds ("fungus-like"): Decomposers, consume dead plants and animals.

Fungi

• Characteristics: Heterotrophic (rely on consuming others for nutrition) eukaryotes, more closely related to animals than plants, reproduce via spore dispersal, have chitin cell walls. Fungi are decomposers of dead matter, breaking it down to be used in the ecosystem.
• Environmental Impact: Important decomposers, breaking down dead plants and animals.

Plants

• Characteristics: Eukaryotic, have cellulose cell walls, store carbohydrates as starch, photosynthesize (using chlorophyll), have specialized tissues (roots, leaves, stems).

• Evolution and Adaptation: Adapting to live on land involved developing vascular tissues, seeds to protect the embryo, and reproductive structures (flowers and fruit). Early plants were dependent on water and moisture.

• Groups:

  • Nonvascular: Lack vascular tissue (e.g., mosses), reliant on water for reproduction.
  • Seedless vascular: Have vascular tissue but do not produce seeds (e.g., ferns).
  • Seed plants: Have vascular tissue and seeds. Further divided into gymnosperms (no flowers or fruit) and angiosperms (bearing flowers and fruit). Angiosperms produce fruit (from the ovary of the flower), which protects and helps disperse the seeds.

• Vascular Tissue: Xylem transports water, and phloem transports nutrients. This allows for taller stature.

• Seeds: Protect the embryo, aid in long-term survival.

• Flowers/Fruit: Flowers attract pollinators, fruits aid in seed dispersal.

Animals

• Characteristics: Eukaryotic, heterotrophic, mobile at some point in their life cycle, have tissues and body symmetry, similar developmental patterns during embryonic development.
• Vertebrates vs. Invertebrates: Vertebrates have a backbone and spinal cord; invertebrates do not.
• Key Groups: (Note examples are limited and you are responsible for memorizing the examples stated in your lecture).
  • Cnidarians: Jellyfish, corals (have stinging cells).
  • Sponges (Porifera): Lack true tissues.
  • Flatworms
  • Mollusks
  • Arthropods
  • Chordates: (includes vertebrates)
  • Amphibians
  • Reptiles
  • Birds
  • Mammals
  • Marsupials
• Vertebrate Evolution: Fish are the first vertebrates to evolve. Amniotic eggs were a critical adaptation for life on land.

Population Ecology

• Ecology: Study of living organisms and their interactions with the environment.
• Population: Group of the same species living in a given area.
• Population Density: Number of individuals per unit area.
• Dispersion Patterns: Random, clumped, uniform.
• Growth Curves: Exponential (J-shaped) and Logistic (S-shaped).
• Carrying Capacity: Maximum population size an environment can sustain.
• Life History: Characteristics affecting reproduction and survival.
• R- and K-selected species: Differences in reproductive strategies.
• Sustainable Resource Management: Harvesting resources without damaging the resources.

Communities and Ecosystems

• Community: Different populations of organisms living and interacting in the same area.
• Interspecific Interactions:
  • Competition: Different species vying for resources.
  • Predation: One species consuming another.
  • Herbivory: An animal consuming plant material.
  • Parasitism: One species benefits, the other is harmed.
  • Mutualism: Both species benefit.
  • Commensalism: One species benefits, the other is unaffected.
• Trophic Levels: Feeding positions in a food web.
• Foundation Species: Species that create or maintain habitats for other species.
• Invasive Species: Non-native species harming native species.
• Keystone Species: Species with major impacts in their ecosystem, their absence may cause great ecological consequences.
• Ecosystem: Community of organisms and their environment.

Conservation

• Biodiversity: Three main components – genetic diversity, species diversity, and ecosystem diversity.
• Endangered/Threatened Species: Species facing extinction/at risk of extinction.
• Threats to Biodiversity: Habitat loss, climate change, invasive species, overexploitation, pollution.
• Conservation Strategies: Protecting habitats, controlling invasive species, sustainable resource management, and establishing protected areas, among others.