What is environmental science? Rehash, Lecture 1: Rehash, Lecture 1: Environmental Issues & Problems ENV 150. Natural Capital Degradation

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1 Environmental Issues & Problems ENV 150 Guillaume Mauger What is environmental science? Today s Schedule: 1. Review Syllabus, Schedule, Assignments 2. Rehash of last week s topics 3. Biodiversity and Rehash, Lecture 1: Natural Capital =? Rehash, Lecture 1: Natural Capital Degradation Caused by?

2 Rehash, Lecture 1: What is sustainability? Source: Footprint Network What is sustainability? Rehash, Lecture 1: World Commission on Environment and Development Report Our Common Future, 1987 "development that meets the needs of the present without compromising the ability of future generations to meet their own needs." Characteristics of Sustainable Ecosystems: - Biodiversity - Reliance on Solar Energy - Nutrient Cycling - Population Control

3 Rehash, Lecture 1: Seattle area: Rehash, Lecture 2: Spheres Geosphere Atmosphere Hydrosphere Biosphere Color Land Use Dark green Thick forest Light green Vegetation Pinkish Urban areas Bright blue Ice and snow Rehash, Lecture 2: Ecosystems: Components Producers (Autotrophs) Consumers (Primary, Secondary, Tertiary, Omnivores) Decomposers, Detritus Feeders Dynamics e.g., Food chain, Trophic Levels Productivity: GPP / NPP Rehash, Lecture 2: Nutrient Cycles Water Carbon Nitrogen Sulfur Phosphorous

4 Biodiversity and What do we mean by biodiversity? What do we mean by biodiversity? What do we mean by biodiversity? U.S. Office of Technology Assessment: Biological diversity refers to the variety and variability among living organisms and their relative frequency. For biological diversity, these items are organized at many levels, ranging from complete ecosystems to the chemical structures that are the molecular basis of heredity. Thus, the term encompasses different ecosystems, species, genes, and their relative abundance. More than just diversity of species: Diversity of ecosystems Diversity of species Diversity within a species (genetic)

5 Why is biodiversity important? Why is biodiversity important? To humans: Provides food, wood, fibers, energy, medicines For life on Earth: Preserves quality of air/water Preserves fertility of soils Waste disposal, pest control : The Context History of life on Earth:

6 Billions of years ago Formation of Earth s crust, atmosphere and oceans today Billions of years ago Formation of Earth s crust, atmosphere and oceans Small organic molecules form in the sea Large organic molecules form in the sea First protocells form in the sea today Billions of years ago Formation of Earth s crust, atmosphere and oceans Small organic molecules form in the sea Large organic molecule form in the sea First protocells form in the sea today Billions of years ago Formation of Earth s crust, atmosphere and oceans Small organic molecules form in the sea Large organic molecule form in the sea First protocells form in the sea today Single-cell prokaryotes form in the sea -Bacteria -Archaea Single-cell prokaryotes form in the sea Single-cell eukaryotes form in the seas -Amoebae -Ciliates -Flagellates -Heliozoa Cyanobacteria Credit: Micrographia 2 Amoebae Credit: Micrographia

7 Billions of years ago Formation of Earth s crust, atmosphere and oceans Small organic molecules form in the sea Large organic molecule form in the sea First protocells form in the sea today Billions of years ago Formation of Earth s crust, atmosphere and oceans Small organic molecules form in the sea Large organic molecule form in the sea First protocells form in the sea today Single-cell prokaryotes form in the sea Single-cell eukaryotes form in the seas Multicellular organisms form in the seas, and later on land Single-cell prokaryotes form in the sea Single-cell eukaryotes form in the seas Multicellular organisms form in the seas, and later on land Red algae Credit: Berkeley, Palomar College Red algae Humans Credit: Berkeley, Palomar College : Homonids Billions of years ago today Phylogeny: study of evolutionary relatedness Source: Reed et al., PLOS Biology Credit: NASA

8 How does evolution work? The process of Genetic Mutations: random changes in the structure or number of DNA molecules in a cell that can be inherited by offspring Random errors in gene replication, or External agents: radioactivity, x-rays, or mutagens NOTE: all mutations are RANDOM! The process of Natural Selection: The process of Natural Selection: Genetic variability Traits must be inheritable Trait must lead to differential reproduction Genetic variability Traits must be inheritable Trait must lead to differential reproduction Leads to adaptations: heritable traits that enable survival and reproduction Structural, behavioral/sexual, physiological

9 The process of Structural adaptations Fruit and seed eaters Greater Koa-finch Insect and nectar eaters Kuai Akialaoa Natural Selection: Kona Grosbeak Amakihi Akiapolaau Crested Honeycreeper Genetic variability Traits must be inheritable Trait must lead to differential reproduction Leads to adaptations: heritable traits that enable survival and reproduction Structural, behavioral/sexual, physiological Maui Parrotbill Apapane Unknown finch ancestor : Genetic variation how? : Genetic variation how? mutations: random changes in the structure or # of DNA molecules in a cell that can be inherited by offspring mutations: random changes in the structure or # of DNA molecules in a cell that can be inherited by offspring gene flow: introduced genes from a different population (same species)

10 : Genetic variation how? mutations: random changes in the structure or # of DNA molecules in a cell that can be inherited by offspring gene flow: introduced genes from a different population (same species) hybridization: 2 distinct taxa crossbreed to produce fertile offspring Large gene pool - Increases biological fitness of the species Small gene pool - Fewer traits for natural selection - Genetic drift has significant affects - Increased potential of extinction Hunted to near extinction, 30,000 to 1,000 in 1900 : Genetic drift random selection allows maladaptive traits in small populations - probability - chance how? Worms of different color over 4 generations: Common myths about 1. Survival of the fittest = survival of the strongest (strongest may not be fittest) 2. Adaptations occur because they are needed or wanted (purely based on advantage) 3. follows a clear path of improvement and order (random, branching process)

11 Common myths about 1. Survival of the fittest = survival of the strongest (strongest may not be fittest) 2. Adaptations occur because they are needed or wanted (purely based on advantage) 3. follows a clear path of improvement and order (random, branching process) Common myths about 1. Survival of the fittest = survival of the strongest (strongest may not be fittest) 2. Adaptations occur because they are needed or wanted (purely based on advantage) 3. follows a clear path of improvement and order (random, branching process) Common myths about 1. Survival of the fittest = survival of the strongest (strongest may not be fittest) 2. Adaptations occur because they are needed or wanted (purely based on reproductive advantage) 3. follows a clear path of improvement and order (random, branching process) Common myths about 1. Survival of the fittest = survival of the strongest (strongest may not be fittest) 2. Adaptations occur because they are needed or wanted (purely based on reproductive advantage) 3. follows a clear path of improvement and order (random, branching process)

12 Common myths about 1. Survival of the fittest = survival of the strongest (strongest may not be fittest) 2. Adaptations occur because they are needed or wanted (purely based on reproductive advantage) 3. follows a clear path of improvement and order (random, branching process) Behavioral Physiological Structural Genetic drift Coevolution Convergent evolution Speciation through adaptations Speciation through chance/probability Interacting species engage in a back and forth genetic contest Speciation due to human selection Organisms not closely related, independently evolve similar traits due to similar ecological niches