Week 1 Biology (Textbook based)

Scientific thinking

An intellectual activity that involves methodical, objective observation, description, experimentation, and explanation of natural phenomena

Science as a pathway

Science is not just a list of facts but a process for discovering and better understanding the world

Central question of science

“How do you know that is true?”—the foundation of scientific thinking

Example of scientific skepticism

Kellogg’s claim that fortified cereals improved children’s immunity was challenged, tested, and disproven

Scientific literacy

A general, evidence-based understanding of biology and science that enables people to make informed decisions

Benefits of scientific literacy

Helps individuals evaluate claims, make personal health decisions, and engage with social, political, and legal issues involving science

Consequences of lacking biological literacy

Individuals may be misled by experts or false claims for personal or corporate gain

Characteristics of life

Cellular structure, metabolism, sensitivity and responsiveness, homeostasis, growth and reproduction, evolutionary adaptation

Cellular structure

All living organisms have complex, ordered organization of one or more cells that carry out life functions

Metabolism

Ability to acquire, use, and transform energy to perform work

Responsiveness

Living organisms respond and adapt to environmental stimuli

Homeostasis

Ability to maintain relatively constant internal conditions despite external changes

Growth, development, and reproduction

Living things grow, change, and produce offspring

Evolutionary adaptation

Populations change traits over time, leading to adaptations that increase survival and reproduction

Borderline cases of life

Entities like viruses and computer programs challenge strict definitions of life

Themes in biology

Five central ideas unify biology: evolution, structure and function, information flow, energy and matter pathways, and systems

Evolution

Populations change over time, leading to adaptations and diversity of organisms

Structure and function

Physical features of organisms are closely linked to their roles and functions

Information flow

Genetic information carries instructions for traits, passed to offspring, influencing growth and function

Pathways of energy and matter

Organisms transform matter and use energy through chemical reactions for growth, movement, and reproduction

Systems

Life is organized at multiple levels: molecules, cells, tissues, organs, organisms, populations, communities, ecosystems, biosphere

Biodiversity

Variety of genes, species, and ecosystems on earth

Value of biodiversity

Biodiversity has intrinsic (inherent worth) and extrinsic (human-use) value

Examples of biodiversity’s extrinsic value

Taxol from Pacific yew treats cancers

Toxin production in nature

Often evolves as protection against predators but can be co-opted for human medicine

Ecosystem services

Categories of biodiversity benefits (4) : provisioning, regulating, habitat, cultural

Provisioning services

Direct products humans obtain from ecosystems (food, medicine, raw materials)

Regulating services

Benefits ecosystems provide by regulating natural processes (climate regulation, water purification)

Habitat services

Biodiversity provides living spaces and maintains genetic diversity

Cultural services

Non-material benefits such as recreation, spiritual value, and aesthetic inspiration

Levels of biodiversity

Biodiversity occurs at multiple levels: ecosystems, species, genes, alleles

Species richness

Most common way to measure biodiversity, by counting the number of distinct species in an area

Conservation biology

Interdisciplinary field focused on understanding and preserving biological resources and biodiversity

Challenge of conservation biology

Biodiversity has many types of value, making it difficult to balance competing human interests