Ecology and Environmental Challenges

Ecology Definition

• Study of how organisms interact with their environment, determining their distribution and abundance.

The Anthropocene

• Human impact over the past 50 years has significantly altered Earth, with some changes being irreversible
• This period highlights the interconnectedness of everything in nature.

Challenges in Ecology

• Climate change
• Land use change
• Extinction
• Invasive species
• Ecosystem homogenization: environments becoming more similar
• Overexploitation

Levels of Organization in Ecology

• Individuals: a single organism
• Populations: a group of the same species in a specific area
• Community: different species interacting in the same area
• Ecosystem: a community and their physical environment
• Biosphere: all ecosystems

How we learn about ecology

• Observation and natural history:
  • Focuses on direct observation and description of organisms
  • Historical foundation of ecology
  • Modern approaches often combine observation with other methods
• Experimental ecology and Null hypothesis testing:
  • Ecologists began using manipulative experiments and statistical hypothesis testing in the second half of the 20th century.
  • Steps in this process:
    1. Formulate a question based on observation or existing knowledge.
    2. Propose a null hypothesis (focal factor has no effect) and an alternative hypothesis (focal factor has an effect).
    3. Design an experiment to manipulate focal factors and include controls.
    4. Analyze the data and interpret the results.
    5. Use the interpretation to form new questions and restart the process.
  • This process is iterative and self-correcting.

Brain Study Methods

• Researchers examine the brain's structure and function by examining thinly sliced tissues under a microscope.
• Tissue fixation preserves the biological material before slicing.
• Specialized stains highlight different cellular components or structures.
• Myelin is a frequently studied structure.
• Optical Imaging creates a "see-through brain" for observing 3D brain architecture.

Imaging Techniques

• CT uses X-rays to detect structural abnormalities.
• PET measures metabolic activity by detecting radioactive tracers.
• MRI provides high-resolution images of brain structures.
• fMRI measures brain activity by detecting changes in blood flow.
• DTI shows brain connections through white matter tracts.

Recording Brain Activity

• EEG records electrical activity from the brain's surface using electrodes.
• ERP analyzes EEG data to measure brain responses to specific stimuli.
• MEG detects magnetic fields generated by neural activity.
• Single-Cell Recording measures the electrical activity of individual neurons.
• TMS uses magnetic fields to stimulate specific brain regions.

Optogenetics

• Combines genetic engineering with light to control neurons.
• Allows researchers to study the effects of brain activity on behavior and cognition.

Genetic Studies

• Analyze genes and their variations to understand their influence on brain function.

Historical Figures

• Hippocrates believed the brain controlled human thought.
• Phineas Gage suffered damage to the OFC (Orbitofrontal Cortex), leading to personality changes.
• Galen concluded the brain controls cognition and willed actions.
• Descartes proposed the pineal gland controlled the body, a theory later proved wrong.
• Paul Broca discovered that damage to Broca's area impairs speaking fluently.
• Carl Wernicke found that damage to Wernicke's area impairs speech comprehension.
• William James advocated for studying psychology through biology and behavioral modifications.
• B.F. Skinner developed the Skinner box to study reinforcement behaviors in animals.
• Franz Joseph Gall developed phrenology, a pseudoscience that was important for acknowledging the localization of cognitive functions in different brain regions.

Microscopic Methods

• Sectioning allows researchers to slice fixed tissue for examination.
• Histology is the study of the microscopic structures of tissues.
• Lesions refer to injuries or damage to neural tissue.