Ecosystems and Living Organisms: Interactions and Adaptations
Understanding Ecosystems and Their Components
All living things that inhabit our planet belong to a species. Individuals of the same species can breed with each other and produce fertile offspring. Individuals of the same species living in the same area form a population. The set of populations that share a territory and establish relationships with each other is called a community or biocenosis. The territory occupied by a biocenosis, which has specific physical and climatic characteristics, is called a biotope.
The Ecosphere: The Largest Ecosystem
The ecosphere is the most comprehensive ecosystem: it covers the entire planet Earth and its biocenosis. The ecosystem is comprised of:
- The biotope, which can be aquatic or terrestrial and provides the physical environment.
- The biocenosis, composed of all living beings and the relationships between them.
Factors Influencing Ecosystems
- Abiotic factors: These characterize the biotope or physical environment.
- Biotic factors: These are living beings and the relationships established between them.
Key Abiotic Factors
- Temperature: Temperatures below freezing cause death, and excessively high temperatures also limit survival.
- Light: Light is essential for photosynthesis. In aquatic environments, light penetrates with difficulty.
- Humidity: Humidity varies widely in terrestrial environments and determines both the distribution and various features of organisms.
- Chemical composition of soil: Soil is essential for plants, which absorb water and minerals from it.
- Salinity: Salinity is crucial in aquatic environments, distinguishing between fresh and saltwater.
- Pressure: Pressure changes little on land but increases with depth in water.
Relationships Between Living Organisms
- Tolerance limit: The range within which an organism can survive.
- Colonial: Organisms united and interconnected.
- Gregarious: Individuals of different families coming together for a specific objective.
- State: Individuals with clear anatomical differences.
- Symbiosis: Two or more species associate for mutual benefit (mutualism).
- Competition: Individuals of different species compete for resources.
- Commensalism: One species benefits by feeding on another’s leftovers without affecting the latter.
- Predation: A predator stalks and captures prey.
- Parasitism: One individual lives at the expense of another, causing harm.
- Inquilinism: One individual is associated with another of a different species for shelter.
Adaptations of Living Organisms
- Anatomical adaptations: Affect the structure of organs or the body in general.
- Physiological adaptations: Affect the functioning of organs, generating substances to facilitate survival.
- Behavioral adaptations: Affect habits acquired by living things to survive and communicate.
Adaptations to Temperature
- Plants: Reduce leaf surface, form seeds during drought and germinate quickly, lose leaves in winter. Plants resistant to harsh Arctic winters and cold herbaceous plants grow close to the ground to prevent cooling.
- Animals: Develop insulating structures like fat and hair, reduce activity in winter, migrate. Desert animals are often nocturnal. Homeotherms maintain a constant internal temperature, while poikilotherms regulate their internal temperature based on the environment.
Adaptations to Climate
- Plants: In dry climates, plants minimize their leaves, develop extensive roots, and open their stomata in the evenings. Cacti have fleshy stems and small leaves to store water.
- Animals: Reptiles obtain water from food, dromedaries from fat in their humps, and many have exoskeletons to prevent water loss.
Adaptations to Light
- Plants: Increase leaf surface area to capture light, climb, or live on other plants.
- Animals: Diurnal and nocturnal animals have adapted vision. Animals regulate their production cycles according to daylight hours.
Energy and Matter Flow in Ecosystems
Through photosynthesis, plants and algae obtain energy from the sun to produce organic matter. Animals get energy from food, using much of it to create their own organic matter but losing some as heat during growth and movement. When autotrophic and heterotrophic organisms die, microorganisms convert their remains into inorganic matter, restarting the cycle. Thus, the flow of matter in the ecosystem is a closed cycle, allowing matter to be reused many times.
Roles in the Ecosystem
- Producers: Autotrophic organisms like plants and algae that capture solar energy and convert inorganic matter into organic matter through photosynthesis.
- Consumers: Heterotrophic organisms that obtain matter and energy from other living or decaying organic matter.
- Primary consumers (herbivores)
- Secondary consumers (carnivores) that feed on primary consumers.
- Tertiary consumers: Feed on secondary consumers (top predators).
- Decomposers: Bacteria and fungi that decompose organic waste into inorganic matter, making it usable for producers.