Introduction to Living Organisms

• Biology is the study of living organisms
• Biology encompasses the study of their environment
• Biology includes studying the interrelationships between living organisms

Living Organisms

• Living organisms, also known as organisms, exhibit life's characteristics
• These characteristics: organization, metabolism, responsiveness, movement, reproduction, and growth
• Living organisms are highly organized, containing specialized, coordinated parts
• Metabolism is performed through capturing energy or breaking down molecules
• Living organisms respond to stimuli in their environment
• Many organisms are capable of movement
• All living organisms reproduce
• Living organisms grow and develop during their life cycle
• The diversity of life is vast, ranging from single-celled bacteria to complex multicellular plants and animals
• Organisms are classified into taxonomic groups based on evolutionary relationships
• The three domains of life: Bacteria, Archaea, and Eukarya
• Eukarya includes kingdoms like Protista, Fungi, Plantae, and Animalia

Environment

• An organism's environment includes all the external factors that affect its survival and development
• Environmental factors are biotic (living) or abiotic (non-living)
• Biotic factors include interactions with other organisms, such as competition, predation, and symbiosis
• Abiotic factors include temperature, light, water availability, nutrients, and pH
• Organisms adapt to their environment through evolutionary adaptations
• Adaptations can be structural, physiological, or behavioral
• The environment provides resources that organisms need to survive, such as food, water, and shelter
• Different environments support different types of organisms, leading to varied ecosystems
• Ecosystems are complex communities of interacting organisms and their physical environment
• Environmental changes significantly impact living organisms, potentially leading to adaptation, migration, or extinction
• Human activities are major drivers of environmental change, including pollution, deforestation, and climate change

Interrelationships Between Living Organisms

• Living organisms interact in various ways, forming complex relationships within ecosystems
• These interrelationships: competition, predation, symbiosis, and commensalism
• Competition occurs when organisms vie for the same limited resources, such as food, water, or space
• Predation involves one organism (the predator) consuming another organism (the prey)
• Symbiosis is a close and long-term interaction between two or more different species
• Symbiosis can be mutualistic (both benefit), commensalistic (one benefits, the other is unaffected), or parasitic (one benefits, the other is harmed)
• Mutualism is a relationship where both interacting species benefit
• Commensalism is a relationship where one species benefits and the other is neither harmed nor helped
• Parasitism is a relationship where one species benefits at the expense of the other
• Food webs illustrate the flow of energy and nutrients through an ecosystem, showing the interconnectedness of organisms
• Keystone species play a critical role in maintaining the structure and function of an ecosystem
• The removal of a keystone species can have cascading effects on the entire community
• Coevolution occurs when two or more species reciprocally influence each other's evolution
• Mimicry is an adaptation in which one species evolves to resemble another species
• These relationships are essential for maintaining the balance and stability of ecosystems

Importance of Studying Biology

• Studying biology provides a fundamental understanding of life processes
• Crucial to understand how organisms function, interact, and have evolved
• Knowledge of biology is essential for addressing many of the challenges facing humanity
• These challenges include disease, environmental degradation, and food security
• Biological research has led to advances in medicine, agriculture, and conservation
• Biology helps understand human health and disease
• Biology is essential for developing sustainable agricultural practices
• Biology informs conservation efforts to protect biodiversity and ecosystems
• Studying biology promotes critical thinking and problem-solving skills
• Biology encourages an appreciation for the diversity and complexity of life
• Essential for making informed decisions about environmental issues and personal health