E&E FINAL REVIEW

Introduction to Ecology and Evolution

  • Course Title: BIO 1400

  • Focus on ecology and evolution principles.

The Age of Earth

  • Earth is approximately 4.55 billion years old.

Diversity of Life

  • Three major branches of living organisms:

    • Archaea: unicellular microorganisms, prokaryotes.

    • Bacteria: unicellular microorganisms, prokaryotes.

    • Eukarya: unicellular or multicellular organisms, eukaryotes.

Understanding Science

  • Term originated from Latin meaning "knowing".

  • Defined as a process for producing empirical knowledge through methodical studies.

  • Hypothesis: A testable proposed explanation for natural phenomena.

Building Blocks of Life

  • Atoms: Smallest particle displaying characteristics of an element.

    • Protons: Positively charged particles.

    • Electrons: Negatively charged particles.

    • Neutrons: Neutral particles.

  • Element: A substance that cannot be simplified through chemical reactions.

Atoms and Molecules

  • Most atoms strive to lose or gain electrons to achieve stability.

  • Molecules: Groups of atoms that exist as an individual unit with unique properties.

  • Compounds: Molecules comprising different kinds of atoms, usually bound by covalent bonds.

Macromolecules

  • Four critical classes of macromolecules:

    • Carbohydrates

    • Lipids

    • Nucleic acids

    • Proteins

Food Chains

  • Defined as linear sequences of organisms where nutrients and energy flow as one organism consumes another.

    • Each organism occupies a specific trophic level.

    • Trophic levels:

      1. Producers: Photosynthetic organisms.

      2. Primary consumers: Herbivores.

      3. Secondary consumers: Carnivores.

      4. Apex consumers: Organisms at the top of the food chain.

Biological Magnification

  • Refers to the increasing concentration of toxic substances in successive trophic levels.

    • Examples:

      • DDT: A pesticide banned in the 1970s.

      • PCB: Polychlorinated biphenyls, banned in 1979.

    • A notable case in Saginaw Bay, Lake Huron, showed PCB concentrations increasing from phytoplankton to apex consumers.

    • Heavy metals like mercury, lead, and cadmium are of concern, with guidelines recommending limited consumption of certain fish.

Carbon Cycle

  • Carbon is found in all organic molecules, significantly influenced by fossil fuel usage since the 1800s, contributing to climate change.

  • The carbon cycle consists of two subcycles:

    1. Rapid carbon exchange among living organisms.

    2. Long-term carbon cycling through geologic processes.

Soil Formation

  • Arun from interactions among various factors:

    • Climate

    • Parent material

    • Topography

    • Vegetation

    • Living organisms

    • Time

  • Soil composition includes mineral matter and organic matter, with pore spaces for water and air.

Soil Profile

  • Soil comprises horizons in undisturbed areas:

    • O and A horizon: rich in organic matter (topsoil).

    • E horizon: subsoil (leached).

    • B horizon: accumulation of materials.

    • C horizon: weathered parent material.

    • R horizon: bedrock.

Soil Texture

  • Descriptive of the proportions of sand, silt, and clay:

    • Ideal agricultural soils: loams, with balanced proportions of sand, silt, and clay.

Geological Formations

  • Rocks undergo cyclical processes of formation, destruction, and reform.

  • Types of rocks:

    • Igneous (e.g., granite).

    • Sedimentary (e.g., shale).

    • Metamorphic (e.g., marble).

Populations and Species

  • Population: A group of interacting organisms of the same species.

  • Metapopulation: Consists of sub-populations occupying distinct habitats with migration connections.

Distribution Patterns

  • Distribution models assess the spatial distribution of individuals:

    • Uniform: evenly spaced.

    • Random: unpredictable distribution.

    • Clumped: grouped arrangements.

Population Dynamics

  • Population size and density reflect characteristics at a particular time.

  • Demography: Statistical study of population changes, focusing on birth rates, death rates, and life expectancies.

  • Data illustrated using life tables.

Survivorship Curves

  • Graphs depicting survival rates across different age intervals:

    • Type I: Low mortality early; significant mortality in older ages.

    • Type II: Constant mortality rate across lifespan.

    • Type III: High mortality in early stages; lower in mature organisms.

Logistic Growth Model

  • S-shaped curve representing population growth phases:

    1. Exponential growth phase (ample resources).

    2. Slowing growth phase (limited resources).

    3. Carrying capacity phase (stable population size).

Demographic-Based Population Models

  • Life history adaptations impact population growth.

  • K-selected vs. r-selected species represents a continuum of reproductive strategies.

Characteristics of Communities

  • Communities encompass structure and dynamics:

    • Species richness: Diversity of species in an area.

    • Species evenness: Relative abundance of species.

  • Foundation Species: Primary producers crucial for community structure (e.g., kelp).

Keystone Species

  • Species with a significant community impact, historically viewed as top carnivores; now recognized in other roles (e.g., pollinators, seed dispersers).

Community Dynamics

  • Changes in community structure over time; includes succession processes.

    • Primary Succession: Colonization of newly formed land.

Ecological Niche

  • The role of a species within its environment, including:

    • Environmental factors.

    • Resource availability and competition.

    • Biological factors (predators, pathogens).

Law of Competitive Exclusion

  • Asserts that no two species can occupy the same niche simultaneously without competition driving one out or leading to adaptation.

Resource Partitioning

  • Occurs when overlapping niches force species to adapt, shift ranges, or become extinct, allowing coexistence through specialization.

Species Interactions

  • Symbiotic interactions include:

    • Mutualism: Both species benefit.

    • Commensalism: One species benefits, other is unaffected.

    • Parasitism: One benefits at the expense of the other.

Biomes

  • Regional groupings of climax plant communities reflecting similar conditions globally, classified by climax vegetation.

The Central Dogma of Molecular Biology

  • Conceptual framework: DNA -> RNA -> PROTEINS.

DNA Structure

  • Composed of nucleotides:

    • Four bases: Adenine (A), Thymine (T), Cytosine (C), Guanine (G).

    • Double-stranded: Strands are complementary and anti-parallel.

    • Hydrogen bonds link the complementary strands.

Function of Proteins

  • Proteins are responsible for the majority of biological roles in cells.

  • Composed of amino acid chains, serving various cellular functions.

Conditions for Natural Selection

-A breed requires:

  1. Reproduction.

  2. Genetic inheritance.

  3. Genetic variation.

  4. Competition.

  5. Variants having different fitness levels.

Evolutionary Fitness

  • Defined as the number of offspring produced by an individual relative to others in its population.

Adaptations

  • Features that enhance survival and reproduction in specific environments.