Chapter 1: Biology: The Science of Life (Essentials of Biology, 7th Edition)

Key concepts from the lecture notes covering life characteristics, organization, energy, homeostasis, reproduction, evolution, taxonomy, scientific method, and societal challenges.

What is the smallest, most basic unit of life?

Cell

Are organisms unicellular or multicellular?

They may be unicellular or multicellular.

What are tissues?

Made up of similar cells.

What is an organ?

Made up of tissues.

What is an organ system?

Organs working together.

What is an organism?

Organ systems working together to support an individual.

What is a population?

Members of similar organisms within a particular area.

What is a species?

All populations of similar organisms capable of interbreeding.

What is a community?

Interacting populations in a given area.

What is an ecosystem?

Communities interact with the physical environment.

What is the biosphere?

The zone of air, land, and water at the surface of the Earth where living organisms are found.

List the levels of biological organization from atom to biosphere.

Atom → Molecule → Cell → Tissue → Organ → Organ System → Organism → Population → Species → Community → Ecosystem → Biosphere.

What does life require?

Materials and energy.

What is energy?

Capacity to do work.

What is metabolism?

All chemical reactions occurring in the cell.

What is the ultimate energy source for nearly all life on Earth?

The Sun.

What process transforms solar energy into chemical energy?

Photosynthesis.

What defines how ecosystems function?

The energy and chemical flow between organisms.

Why does energy not cycle in ecosystems?

Energy flows through the system and is largely lost as heat; solar energy and producers drive the flow.

Who are the main players in energy flow in ecosystems?

Producers, consumers, and decomposers.

What is homeostasis?

An internal environment that remains within a set of physiological boundaries.

How do living organisms respond to their environment?

By interacting with the environment; responses often involve movement.

How do bacteria reproduce?

By binary fission (splitting in two).

What is DNA?

The blueprint; genes are made of DNA.

What are adaptations?

Modifications that make organisms suited to their way of life.

What is evolution?

Process by which populations accumulate adaptations over time to become more suited to their environments.

What is natural selection?

Process that results in a population adapted to the environment; better-suited individuals tend to survive and reproduce more.

What is 'descent with modification'?

All evolved from a common ancestor with modifications over time.

What is binomial nomenclature?

Genus and species epithet; universally used to identify organisms.

What are the three domains?

Archaea, Bacteria, and Eukarya.

Which domains are prokaryotic?

Archaea and Bacteria.

What are the four eukaryotic kingdoms?

Protists, Plants, Fungi, Animals.

What are protists?

A diverse group of eukaryotes; many are single-celled, some multicellular.

What are plants?

Multicellular photosynthesizers.

What are fungi?

Multicellular decomposers (molds and mushrooms) that help decompose dead organisms.

What are animals?

Multicellular organisms that ingest food.

What is a binomial name example?

Pisum sativum—the garden pea.

What is the scientific method?

Observation leads to a hypothesis; predictions are tested by experiments; data are collected; conclusions are drawn; the process is repeatable.

What is a hypothesis?

A possible explanation for an event that can be tested.

What is a scientific theory?

A well-supported explanation for natural phenomena; includes cell theory and gene theory; evolution is a unifying concept.

What is a controlled study?

An experimental design with a control group and randomization to reduce variance.

What is a double-blind study?

Neither participants nor researchers know which group is which to prevent bias.

Why is peer review important?

It ensures reliability; findings are shared and guide future discovery.

What is technology in science?

The application of scientific knowledge for practical purposes.

What drives climate change?

An imbalance in carbon cycling; more CO2 is released than ecosystems can remove.

What was atmospheric CO2 around 1850?

About 280 ppm.

What is biodiversity?

Variation in life on Earth; the numbers of different species.

How many species are estimated to exist on Earth (excluding bacteria)?

About 8.7 million; around 2.3 million classified.

What is extinction?

Death of an entire species or taxonomic group; many may be in danger of extinction.

What are emerging diseases?

Diseases relatively new to humans (e.g., SARS, MERS, COVID-19).

What are reemerging diseases?

Diseases that reappear after a period of quiescence (e.g., Ebola outbreak 2014–2015).