Introduction to Diversity

Introduction to Diversity (Lesson 1)

• Genetic Diversity: Variation in genes within a species, like hair color or height in humans.
• Species Diversity: Variety of species in an ecosystem, such as different animals in a forest.
• Ecosystem Diversity: Different ecosystems and habitats, for example, deserts and rainforests, where trees vary in size and shape.

Human Impacts on Diversity

• Causes of Biodiversity Loss include pollution, exploitation of natural resources, climate change, and invasive species.
• Pollution: Introducing harmful substances (air, water, noise, light, soil) into the environment.
• Exploiting Natural Resources: Overfishing, deforestation, and mining, leading to habitat loss.
• Climate Change: Coral bleaching occurs when water temperatures are too warm, causing coral to expel algae, which gives it color.
• Invasive species: Non-native organisms (plants, animals, bacteria, and fungi) that harm an ecosystem; outdoor cats are a significant invasive species due to their impact on mice and birds.

Classification/Taxonomy (Lesson 2)

• Seven Major Taxa (Kids Prefer Candy Over Fresh Green Salad):
  • Kingdom: Most general.
  • Phylum.
  • Class.
  • Order.
  • Family.
  • Genus.
  • Species: Most specific.
• Species: A group of living things that can reproduce together.
• Morphology: Study of an organism's body shape and features for classification.

Binomial Nomenclature

• Carl Linnaeus developed scientific naming system.
• Genus name is always capitalized, and the species name is lowercase, and both are italicized.

Taxonomy - Dichotomous Keys (Lesson 3/4)

• Dichotomous keys are divided into two parts stating, used to identify organisms.
• Includes two choices for each characteristic (yes or no).

Phylogeny - Phylogenetic Trees (Lesson 3/4)

• Phylogeny compares existing species with their ancestors.
• Phylogenetic trees show the evolutionary relationships between organisms.
• Taxonomy groups organisms into taxa.

The Three Domains (Lesson 5)

• Eukarya: Includes animals, plants, fungi, and protists (eukaryotic cells).
• Bacteria: Common bacteria (prokaryotic cells).
• Archaea: Extreme environment bacteria (prokaryotic cells).
• There are three domains of life: Eukaryotic, Bacteria, and Archaea.
• Eukaryotic domain includes living organisms, such as people and animals.
• Bacteria covers any type of bacteria.
• Domains are the highest taxonomic rank.

Eukaryotes vs Prokaryotes (Lesson 5)

• Feature: Nucleus
  • Eukaryotes: Present
  • Prokaryotes: Absent
• Feature: DNA
  • Eukaryotes: Linear (inside nucleus)
  • Prokaryotes: Circular (floating in cell).
• Feature: Organelles
  • Eukaryotes: Membrane-bound
  • Prokaryotes: No membrane-bound organelles.
• Feature: Examples
  • Eukaryotes: Humans, animals, and plants
  • Prokaryotes: Bacteria and archaea.

General Characteristics of Animals and Protists (Lesson 6 and 7)

• Animal Kingdom (Chordates):
  • Vertebrates: paired appendages, bone skeletons, vertebrae, and complex brains.
  • Amniotic Egg: Provides a protective outer shell, allowing embryo development.
• Protist Kingdom:
  • Most diverse kingdom (unicellular and multicellular eukaryotes).
  • Live in moist environments.
  • Some are autotrophs (producers); others are heterotrophs (consumers).
  • Key Role in Ecosystems: Forms the base of aquatic food chains.
  • Examples: Algae, amoebas, and paramecium.

Phylum: Echinoderms

• Invertebrate marine animals.
• Hard, spiny covering or skin.
• Up to 10 cm in length or diameter and radial symmetry.

Importance of Protists

• Play a key role in aquatic ecosystems.
• Major producer (autotrophs) in the ocean.
• Can be heterotrophs, consuming other organisms for energy, and a large source of aquatic food chains.
• Some species can control the growth of seaweed in coral reefs and alter the structure of seafloor sediments.
• Some are parasites (malaria, beaver fever).
• Many species of protists are used for food, like seaweed.

Characteristics and Origin of Protists

• Most diverse kingdom and made of eukaryotic cells.
• Can be unicellular or multicellular, contains the smallest and largest eukaryotes.
• Live in moist environments.
• Origin:
  • Protists were the first eukaryotes (have a nucleus and membrane-bound organelles).
  • Internal membrane bound organelles likely developed from an ancestral prokaryotic cell.
• Classifying protists:
  • They are autotrophs (energy from photosynthesis) and contain chlorophyll.
  • Can be single-celled or very large (like seaweed).

Importance of Prokaryotic (Lesson 8)

• Bacteria are responsible for many diseases, where infectious bacteria are called pathogens.
• Majority of bacteria and some archaea are positive and necessary for survival.
• Play a key role in the ecosystem:
  • Decomposers.
  • Nutrient cycles.
  • Photosynthetic bacteria are major producers of oxygen.
• Used in digestion and in the production of milk, cheese, yogurt, and chocolate.
• Bacteria are used to produce antibiotics.

Bacteria Cell Structure

• Cell walls/membranes:
  • Inner Cell Membrane: Regulates transport of substances into and out of the cell.
  • Middle Cell Wall: Made of peptidoglycan, strengthens and maintains cell shape.
  • Outer Capsule: Protects DNA containing chromosome in a region called the nucleoid.
• Ribosomes: Scattered in the cytoplasm and help with protein synthesis.
• Flagella: Hair-like projections for movement.
• Pili: Small hair-like structures that attach to other cells or surfaces.
• Plasmids: Some bacteria have small loops of DNA containing a few genes.

Bacterial Metabolism

• • Bacteria are diverse in how they obtain nutrients and energy:
    • Photoautotrophs get their energy from photosynthesis.
    • Chemoautotrophs get their energy from hydrogen, sulfur, or iron compounds.
    • Heterotrophs get their energy from consuming organic matter from organisms.
• Metabolism that uses oxygen to produce energy is called aerobic cellular respiration (all plants and animals are aerobic).
• Metabolism that does not use oxygen to produce energy is called lactic acid fermentation and alcoholic fermentation.

Bacterial Reproduction

• Binary Fission: The division of one cell into two identical cells (main type of reproduction).
• Conjugation: Two cells join to share genetic information via a sex pilus "bridge," where copies of plasmids are exchanged, leading to increased genetic diversity.
• Transformation: A process where a bacterial cell takes in and uses a piece of DNA from its environment.
• Mistakes in copying DNA leads to mutations, changing genetic makeup, and increased genetic diversity.

Bacteria Diseases

• Bacteria cause diseases like strep throat, tuberculosis, and food poisoning; antibiotics treat or slow bacteria growth, though misuse can lead to antibiotic resistance.

Archaea

• Originally thought of as bacteria.
• They are prokaryotic and unicellular organisms.
• Live in extreme environments.
• Unique cell membrane and walls; cell wall lacks peptidoglycan.
• Types of archaea:
  • Methanogens: Live in low-oxygen environments, like sediments of lakes and swamps.
  • Halophiles: Salt-loving organisms that are in places like the Dead Sea and food preserved with salt.
  • Thermophiles: Live in extremely hot conditions, like hot springs and thermal vents.
  • Psychrophiles: Live in extreme cold conditions, like in the Arctic and cold ocean depths.

Fungi Characteristics (Lesson 10)

• Can be unicellular or multicellular and made of eukaryotic cells; unlike plants, they are heterotrophs.
• They have external digestion, where food does not enter their bodies. The fungus grows next to the food and release digestive enzymes.
• Mushrooms get energy from other living or dead organisms.
• Most of the fungus grows below the surface.
• Below the surface, fungi are composed of branching networks of filaments called Mycelium.
• The filaments in the mycelium are called Hyphae, which are very thin, long tubes of cytoplasm containing nuclei, with cell walls made of Chitin.
• Hyphae form the "fuzz" of mold and are the reproductive systems of many fungi.
• Single-celled fungi (yeast!) are used in the production of alcohol and food.
• Fungi classification and phylogeny:
  • Fungi vs Plants: Both are multicellular eukaryotes, sessile (stationary), and often grow on the ground.
  • Plants are autotrophs (make their own food), fungi are heterotrophs (consume other living things for energy).

Fungi Types

• Basidiomycota: Includes mushrooms, which reproduce using spores released from the gills underneath their caps; the gills have a structure, called basidia, which produced spores.
• Zygomycota: Includes molds, like the kind on bread, which reproduce through easily spread spores.
• Hyphae grow into a large mycelium; when mature, the mushroom cap grows, repeating the process

Importance of Fungi

• Major decomposers and enable nutrient cycling.
• Responsible for some plant and animal diseases, e.g., athletes foot, ringworm.
• Production of food, alcohol, and penicillin (antibiotic).
• Symbiotic relationship with plants.

What is a Virus?

• Microscopic infectious agent that cannot reproduce on its own; it must infect a living cell to reproduce.
• Virus means toxin or poison: infections, non-living toxins (they have no cells).
• Very small: 10x smaller than bacteria.
• Causes disease in plants and animals.
• Classification: Viruses are grouped by their shape, the type of genetic material they have (DNA or RNA), and what kind of organism they infect.
• Viruses can infect bacteria, called a bacteriophage.

Virus Structure

• All viruses consist of genetic material (either RNA or DNA) surrounded by a protein capsid.
• Proteins spikes allow virus to attach to host cells.

Virus Cycles

• Virus Cycles:
  • Lytic Cycle is when a virus takes over a cell to make so many copies that the cell bursts.
  • Lysogenic Cycle is when a virus hides inside a cell's DNA and sits dormant.
• Process:
  • Lytic cycle:
    • Virus binds to host cell and inserts DNA.
    • DNA is replicated and new viruses assembled (new DNA and capsid).
    • The host cell will rupture (burst), releasing the virus into its surroundings.
  • Lysogenic cycle:
    • Virus binds to host cell and inserts DNA (the viral DNA remains dormant).
    • The cell grows and divides normally but includes dividing the viral DNA.
    • When triggered by an environmental change, the viral DNA becomes active and enters the lytic cycle.
• Vaccinations: Help protect against viruses by teaching the immune system how to recognize and fight them.

Plant Characteristics (Lesson 11)

• Plants can be massive or small and are multicellular eukaryotic organisms.
• Sessile (can't move from a place to another).
• Autotrophs: Nearly all perform photosynthesis.
• Cell walls with cellulose and have male and female reproductive plants. -Adaptation
  • Cuticle: Plants have a flexible waxy coat on their outer surface to prevent water loss.
  • The Stomata: Allow plants to take in carbon dioxide from the atmosphere and open plus close to allow for movement of gases.

Diversity of Plants

• Bryophytes (simple plant):
  • Includes the mosses do not have a vascular system or seeds.
  • They reproduce with a sperm which swims to the egg for sexual reproduction.
  • Must live in moist environment, reproduce asexually with spores spread (via wind or water).
• Lycophytes and pterophytes (vascular plants):
  • Consist mainly of ferns and have vascular systems.
  • Seedless plants that sexually reproduce with sperm and eggs asexually, reproduce with spores.
• Gymnosperms (seed plants):
  • Pines, conifers, junipers, and vascular plants reproduce using pollen (sperm does not need to swim to egg).
  • Female cones produce seed cones, and male cones produce pollen cones.
• Angiosperm (flowering plants):
  • Complex vascular system seedplants produce flowers .
  • Flowers are like cones and produce pollen and eggs.
  • When fertilization (when male pollen reaches the female ovule), the plant produces a seed.
  • Seed is encased in fruit.

Vascular System in Plants

• A developed vascular system that has roots, stems, and leaves.
• Consists of: Xylem: Transports water and salts from the roots to the plant. Phloem: Transports sugars from the leaves to the plant.
• Allows plants to grow to great heights to reach more sunlight
• Lignin: Makes the cell wall rigid and is part of the woody tissue.
• Phylum: Includes Bryophytes (mosses), Pteridophytes (ferns), Gymnosperms (cone-bearing plants), and Angiosperms (flowering plants)