Evolution and Natural Selection Quiz

Biomes and Biodiversity

• Biomes are large communities defined by climate, including temperature and precipitation patterns. These patterns also shape the organisms and vegetation adapted to live in those areas.
• Biomes are a large geographic area where ecosystems are similar.
• Objectives for the lecture include identifying abiotic and biotic components, understanding factors that affect life within a biome, recognizing biodiversity within biomes and their resilience to change, and identifying threats to Earth's biomes.

Abiotic Factors

• Abiotic factors are non-living chemical and physical components of the environment, crucial for life.
• Inorganic compounds, lacking carbon-hydrogen bonds, are key abiotic components.
• Abiotic factors impact organism survival, growth, reproduction, and influence the types and numbers of species that thrive in a biome.
• Examples include air (oxygen, carbon dioxide, nitrogen), water, sunlight, soil minerals, and humidity.

Biotic Factors

• Biotic factors are living components of an ecosystem, composed of carbon-hydrogen compounds.
• Biotic factors have both direct and indirect impacts on a biome, affecting interactions within the ecosystem (e.g., predation, food chains, waste cycles, disease).
• Examples include viruses, bacteria, fungi, plants, animals, insects, and parasites.
• Organic molecules like DNA, RNA, proteins, lipids, and carbohydrates are also considered biotic components.

Hierarchy of Life on Earth

• Organism: A single living individual.
• Population: Organisms of the same species that can breed and produce offspring.
• Community: Many different species interacting.
• Ecosystem: A community of organisms interacting with their abiotic components.
• Biome: Extensive ecosystems that occupy large geographic regions.

What is a Biome?

• Biomes are defined by global climate patterns.
• Long-term temperature and precipitation patterns define the types of organisms found in each biome.

What is Climate?

• Climate is long-term patterns of weather, occurring over decades or centuries.
• Temperature and precipitation are the main controlling factors.

Major Factors Controlling Climate

• Temperature - Location determines if a biome is hot, warm, or cold.
• Precipitation - Amount of water in an area.
• Tilt of Earth on its axis - Causes seasons (spring, summer, fall, winter).
• Sun - Primary energy source for Earth's climate.
• Latitude - Distance from the equator affects temperature.
• Elevation - Higher altitudes are typically colder.
• Mountain ranges/landforms - Impact how precipitation, moisture, temperature and other elements are affected.
• Ocean currents - Influence temperatures along coastlines.
• Winds - Direct moving elements that can influence how weather and temperature is disbursed.
• Vegetation - Plants absorb moisture from the air affecting the climate.
• Human activity - Deforestation, burning fossil fuels and urbanization can have an influence.

Climograph

• A climograph is a graph that displays monthly average temperature and precipitation data for a location.
• Climographs are an easy way to visualize the location's climate.

Earth's 4 Seasons

• Earth's tilt on its axis causes seasons as the sun's direct rays shift throughout the year.
• March/September = equal sunlight on both hemispheres.
• June = Direct sunlight on Northern Hemisphere
• December = Direct sunlight on Southern Hemisphere

Biome Types

• A global map displays a variety of biomes (ice sheet and polar desert, tundra, taiga, temperate broadleaf forest, etc.)
• Biomes are categorized based on their dominant vegetation types.

Earth's Biomes

• The exact number of biomes is debatable, dependent on classification methods used.
• Differences in climate create distinct biome characteristics.
• Transition zones (ecotones) exist between biomes, where characteristics are shared.
• Climate change causes biome shifts

Three Broad Categories of Biomes

• Marine
• Freshwater
• Terrestrial

Climate

• Temperature and precipitation define Earth's biomes.
• Temperature variations occur with latitude and altitude.
• Temperature in general decreases with increased altitude.

Whittaker's Biome-Types

• Whittaker's biome-types are categorized by climate and vegetation patterns.
• Biomes such as tropical rainforests are hot and wet, while tundras are cold and dry.

Vegetation in Biomes

• Vegetation type is based on climate, precipitation, latitude, altitude, animal species, etc.
• Each biome requires understanding species interactions and nutrient needs within.
• Organisms are adapted to live within temperatures of a particular range.

Forces of Evolution

• Mutation: DNA sequence changes.
• Gene Flow: Movement of genetic variation between populations.
• Genetic Drift: Change in gene frequency due to random mating.
• Natural Selection: Favors better-adapted organisms, leading to greater reproduction amongst those with traits suited to the prevailing conditions.

Evolution by Natural Selection

• Natural selection is a slow process occurring over thousands to millions of years.
• Climate change drives the evolution of a species.
• Extinction occurs when climate changes to a degree impossible for organisms to adapt to.

Natural Selection Types

• Stabilizing selection: Favors the norm, selects against extremes.
• Directional selection: Continuously favors an extreme form.
• Disruptive selection: Favors two extremes, selects against the intermediate form.

Adaptation

• Adaptation = characteristic allowing an organism to survive and reproduce in a specific biome.
• Populations within a biome often have shared adaptations.
• Adaptations may involve physical changes or behavior changes.

Physical Adaptations

• These adapt to physical features or traits such as shape, color, coverings, movement, and size.
• Adaptations depend on the changing environment in the biome.
• Examples: webbed feet, strong beaks, camouflage, and scales.

Behavioral Adaptations

• Adapt to activities performed for survival and reproduction, dependent on the environment in the biome.
• Adapting to activities such as defense mechanisms, migration, hibernation, and mating dances/calls.
• Instincts or learned behavior can help drive adaptation.

Genetic Diversity

• Genetic diversity is important for long-term adaptation and growth of populations.
• Greater diversity allows for greater resilience to future changes.

Biodiversity, Hotspots and ecosystem services

• Biodiversity: The variety of life on Earth.
• Biodiversity hotspot: Areas with high biodiversity but also high endangerment of species.
• Ecosystem services: Essential natural processes that support human life.
• Managed ecosystems: Include farms, croplands, rangelands, aquaculture, etc., which also require maintenance of diversity.
• Human activities affect both natural ecosystems and their service provisions.
• Human health: Many medicines have origins in natural substances.
• Agriculture: Wild species gene adaptation and diversity contributes to future domestic species' food supply.

Major Threats to Biodiversity

• Habitat loss.
• Overharvesting of natural resources.
• Pollution.
• Invasive species.
• Climate change.
• Human population growth.
• Other human activities such as urbanization, logging, and agriculture.

21st Century Ecological Sensitivity

• Degree to which ecosystems can adapt to future climate change.
• Human impact and future climate change can have dramatic impacts.

Extinction Rates

• Current extinction rates are significantly higher than the background rate.
• Human actions contribute to higher rates of extinction.

How can we protect and preserve biodiversity?

• Pass legislation and treaties.
• Restore damaged environments.
• Set aside protected areas.
• Regulate human activity in these areas.
• Protect individual species through captive breeding programs.