Biology: How Life Works Unit 4 - History of Earth & Human Society

Biology: How Life Works Unit 4: History of Earth & Human Society

Course Information

  • Modified by KSU EEOB: Morris, Hartl, Knoll, Lue, Michael Heitz, Hens, Lozovsky, Merrill, Phillis, Pires, Liu

  • Copyright © Macmillan Learning

Announcements

  • Group writing 2 assignment due on Nov 21 at 11:59 pm.

  • Bonus activity worth 10 points is available in D2L discussion; complete by Nov 21 at 11:59 pm to earn points.

  • Unit 4 review quiz and Achieve assignments due on Dec 1 at 11:59 pm.

  • Exam 2 scheduled for Tuesday, Dec 2.

  • Comprehensive review class on Thursday, Dec 4.

  • Final exam on Tuesday, Dec 9 from 1 pm - 3 pm.

Week 14 Learning Objectives

  1. Relate species loss and ecosystem disruption to ecological, evolutionary, and societal consequences.

  2. Compare strategies used in conservation biology to mitigate habitat degradation, loss, and biodiversity loss.

  3. Describe approaches to counteract climate change.

  4. Examine what it means for humans to live sustainably.

Succession: Ecology in Microcosm (pg 1007)

  • Key Questions:

    • What natural processes are being accelerated or disrupted by human activity?

    • Which ecosystem services are lost as succession is sped up?

    • How might climate change amplify these human impacts?

Answers to the Questions

  1. **Natural Processes Disrupted:

    • Human activities such as agricultural runoff (excess nitrogen and phosphorus), logging, fire suppression, and invasive species introduction speed up the natural succession of ponds and forests.

    • These actions accelerate nutrient deposition and alter species composition, pushing ecosystems toward later successional stages faster than natural rates.

  2. Ecosystem Services Lost:

    • Water purification (pond ecosystems fill in faster, reducing aquatic habitat).

    • Habitat provision for diverse aquatic and terrestrial species.

    • Nutrient cycling and carbon storage as forest composition changes.

    • Regulation of biodiversity—loss of species interactions and food web complexity.

  3. Climate Change Impacts:

    • Climate change increases disturbance frequency and intensity (e.g., fires, droughts, storms), causing ecosystems to reset to earlier successional stages more frequently.

    • Alters temperature and precipitation patterns, compounding nutrient runoff effects and accelerating species turnover.

    • Results in greater ecosystem instability and reduced resilience.

Levels of Biodiversity

  • Genetic Diversity:

    • Regulates all biological processes and increases the ability of organisms to cope with environmental stressors and diseases.

  • Species Diversity:

    • Maintains the balance of communities and food webs.

  • Ecosystem Diversity:

    • Provides “Ecosystem Services” critical for life sustenance.

Importance of Diversity from a Biological Perspective

Ecosystem Functions:

  • Ecosystems purify air and water.

  • Detoxify and decompose waste.

  • Crop pollination and pest control.

Ecological Consequences of Biodiversity Loss

  1. Diversity Significance:

    • There are approximately 500,000 species of photosynthetic organisms, contributing to ecosystem processes.

    • Photosynthetic organisms contribute to carbon transfer from CO2 to organic carbon via light, water, and nutrient availability.

  2. Impacts on Carbon Cycle:

    • Diverse organisms maintain geochemical cycles through feeding roles and predator-prey relationships important for smooth nutrient cycling (N and P cycles).

Evolutionary Consequences of Biodiversity Loss

  1. Linkages to Biological Cycles:

    • Biogeochemical cycles connect life, evolution, and Earth’s environment over extended periods.

    • Species diversity impacts short-term cycles such as carbon dynamics within food webs, while long-term cycles shape significant evolutionary changes and environmental transformations in Earth’s history.

  2. Historical Baselines:

    • Hot springs provide insight into early Earth ecosystems and biodiversity loss potentially leading to simpler, microbe-dominated systems in modern contexts.

iClicker Questions

  1. Hot Springs and Biodiversity Loss:

    • A. Biodiversity loss could reset ecosystems to simpler, microbe-dominated systems.

    • B. Biodiversity loss will lead to higher rates of vertebrate evolution.

    • C. Microbial ecosystems are poor models for modern ecological change.

    • D. Evolutionary consequences only occur in multicellular organisms.

Effects of Biodiversity Loss

  1. Reduced Ecosystem Stability:

    • Fewer species translate to lower resilience against disturbances like fires or hurricanes (example: diverse forests recover faster after storms than monocultures).

  2. Lost Opportunities for Medicine & Innovation:

    • About 25% of modern medicines are derived from natural sources (example: the Pacific yew tree yielding cancer drug Taxol).

    • Extinction equates to potential loss of valuable genetic material for research.

  3. Disrupted Natural Pest Control:

    • A decrease in predators leads to an increase in pest populations, necessitating greater pesticide use which harms ecosystems and reduces biodiversity.

  4. Human Well-being and Biophilia:

    • Humans possess an innate connection to nature (biophilia), which supports mental health and creativity.

    • Biodiversity loss limits access to green spaces, increasing stress and anxiety.

Loss of Diversity and Food Security

  • Low genetic diversity in crops elevates vulnerability to pests and climate changes (example: disease like Late Blight caused mass starvation and migration).

  • Cultural impacts include the decline of traditional farming methods, as seen in Bangladesh where high-yield monoculture replaces local rice varieties, leading to the fading of cultural traditions.

Evolution of Conservation Biology

  1. From Individual Species to Ecosystem Resilience:

    • Trends in conservation have shifted focus from individual species (i.e., charismatic species) to protecting critical or keystone species that stabilize ecosystems.

    • Example: The Whooping Crane Recovery Program focuses on intensive management through captive breeding and migration training to maintain populations.

  2. Ecosystem-Level Conservation:

    • Current strategies emphasize maintaining ecological processes and biodiversity hotspots as a proactive measure against degradation.

    • Integrated Pest and Pollinator Management (IPPM) promotes habitat diversity and environmentally friendly practices.

Sustainability and Sustainable Development

  1. Definitions:

    • Sustainability: Meeting present needs without compromising future generations.

    • Sustainable Development: Balancing human needs with nature protection, emphasizing renewable resources and environmental conservation.

      • Examples: Using solar, wind, and hydro energies; improving water conservation practices; setting scientifically informed fisheries limits.

  2. Environmental Education:

    • Plays a crucial role in fostering community engagement and behavioral shifts towards sustainability through campaigns and school programs that emphasize responsible consumption and resource management.

  3. Responding to Rising CO2 Levels:

    • Strategies include expanding the use of alternative energy sources (solar, wind, tidal, and nuclear) to counteract fossil fuel dependency and CO2 production.

    • The significance of citizen actions in reducing emissions is vital as the existing atmospheric CO2 levels won't diminish rapidly.

Cosmic Calendar - Understanding Earth History

  • The Cosmic Calendar compresses the 13.8 billion-year history of the universe into a single year to illustrate significant events:

    • Key Events:

    • January: The Big Bang

    • May: First stars appear

    • July: Formation of the solar system and early life

    • December: Human evolution and significant societal milestones in the last seconds.

Conclusion: The Scientific Understanding of Biology

  • Biology is defined as the scientific expression of our desire to understand nature; this understanding fosters appreciation and ultimately enhances conservation efforts. The course aims to inspire lifelong appreciation and knowledge concerning the biosphere.