Ecosystems Overview

Study Notes

Ecosystems

Definition: A biological community of interacting organisms and their physical environment.
Components:
- Biotic Factors: Living organisms (plants, animals, microorganisms).
- Abiotic Factors: Non-living elements (water, air, soil, sunlight).
Types of Ecosystems:
- Terrestrial: Forests, grasslands, deserts, tundras.
- Aquatic: Freshwater (lakes, rivers) and marine (oceans, coral reefs) ecosystems.
Energy Flow:
- Producers: Organisms that create energy (plants via photosynthesis).
- Consumers: Organisms that consume energy (herbivores, carnivores, omnivores).
- Decomposers: Organisms that break down dead matter (fungi, bacteria).
Nutrient Cycling:
- Water Cycle: Evaporation, condensation, precipitation.
- Carbon Cycle: Carbon fixation, respiration, decomposition.
- Nitrogen Cycle: Nitrogen fixation, nitrification, denitrification.
Ecological Succession:
- Primary Succession: Development of an ecosystem in lifeless areas (e.g., after a volcanic eruption).
- Secondary Succession: Recovery of an ecosystem after disturbances (e.g., forest fire).

Evolution

Definition: The change in the heritable characteristics of biological populations over successive generations.
Mechanisms of Evolution:
- Natural Selection: Process where organisms better adapted to their environment tend to survive and reproduce.
- Genetic Drift: Random changes in allele frequencies in a population.
- Gene Flow: Transfer of genetic material between populations.
- Mutation: Changes in DNA that can create new traits.
Evidence of Evolution:
- Fossil Record: Shows gradual changes in species over time.
- Comparative Anatomy: Homologous structures (similar structures, different functions) suggest common ancestry.
- Molecular Biology: Similar DNA sequences indicate relatedness among species.
Speciation:
- Allopatric Speciation: New species arise due to geographic separation.
- Sympatric Speciation: New species evolve from a single ancestral species while inhabiting the same region.
Evolutionary Theory:
- Charles Darwin: Proposed the theory of evolution by natural selection in the 19th century.
- Modern Synthesis: Integrates Darwin’s theory with Mendelian genetics, explaining how evolutionary processes operate on genetic variations.

Ecosystems

A biological community composed of interacting organisms and their physical environment.
Biotic Factors: Includes all living organisms like plants, animals, and microorganisms.
Abiotic Factors: Encompasses non-living elements such as water, air, soil, and sunlight.
Types of Ecosystems:
- Terrestrial Ecosystems: Includes forests, grasslands, deserts, and tundras.
- Aquatic Ecosystems: Divided into freshwater (lakes, rivers) and marine (oceans, coral reefs).
Energy Flow:
- Producers: Organisms like plants that generate energy through photosynthesis.
- Consumers: Organisms that obtain energy by consuming others, including herbivores, carnivores, and omnivores.
- Decomposers: Organisms such as fungi and bacteria that break down dead matter, recycling nutrients.
Nutrient Cycling:
- Water Cycle: Involves processes like evaporation, condensation, and precipitation.
- Carbon Cycle: Includes carbon fixation, respiration, and decomposition.
- Nitrogen Cycle: Comprises nitrogen fixation, nitrification, and denitrification processes.
Ecological Succession:
- Primary Succession: Occurs in lifeless areas, initiating ecosystem development (e.g., post-volcanic eruption).
- Secondary Succession: Recovery process of an ecosystem following disturbances like forest fires.

Evolution

A change in heritable characteristics of biological populations across successive generations.
Mechanisms of Evolution:
- Natural Selection: Organisms best adapted to their environment are more likely to survive and reproduce.
- Genetic Drift: Random fluctuations in allele frequencies can lead to changes in a population.
- Gene Flow: The process of genetic material moving between populations, increasing genetic diversity.
- Mutation: Alterations in DNA that can produce new traits and contribute to evolution.
Evidence of Evolution:
- Fossil Record: Provides evidence of gradual species changes over geological time.
- Comparative Anatomy: Study of homologous structures (similar anatomy, different functions) suggests common ancestry.
- Molecular Biology: Similarities in DNA sequences among different species indicate evolutionary relationships.
Speciation:
- Allopatric Speciation: New species arise when populations become geographically isolated.
- Sympatric Speciation: New species evolve from a single ancestral species occurring in the same region.
Evolutionary Theory:
- Charles Darwin: Introduced the theory of evolution by natural selection in the 19th century, emphasizing adaptation.
- Modern Synthesis: Combines Darwinian evolution with Mendelian genetics to explain how evolutionary processes act on genetic variation.

Description

Explore the fascinating world of ecosystems in this quiz. Learn about the components that make up biotic and abiotic factors, the different types of ecosystems, and the essential processes like energy flow and nutrient cycling. Test your knowledge on ecological succession and much more!