Table of Contents
1 Evolution, the Themes of Biology, and Scientific Inquiry
Inquiring About Life
CONCEPT 1.1 The study of life reveals common themes
CONCEPT 1.2 The Core Theme: Evolution accounts for the unity and diversity of life
CONCEPT 1.3 In studying nature, scientists make observations and form and test hypotheses
CONCEPT 1.4 Science benefits from a cooperative approach and diverse viewpoints
UNIT 1 THE CHEMISTRY OF LIFE
2 The Chemical Context of Life
A Chemical Connection to Biology
CONCEPT 2.1 Matter consists of chemical elements in pure form and in combinations called compounds
CONCEPT 2.2 An element’s properties depend on the structure of its atoms
CONCEPT 2.3 The formation and function of molecules depend on chemical bonding between atoms
CONCEPT 2.4 Chemical reactions make and break chemical bonds
3 Water and Life
The Molecule That Supports All of Life
CONCEPT 3.1 Polar covalent bonds in water molecules result in hydrogen bonding
CONCEPT 3.2 Four emergent properties of water contribute to Earth’s suitability for life
CONCEPT 3.3 Acidic and basic conditions affect living organisms
4 Carbon and the Molecular Diversity of Life
Carbon: The Backbone of Life
CONCEPT 4.1 Organic chemistry is the study of carbon compounds
CONCEPT 4.2 Carbon atoms can form diverse molecules by bonding to four other atoms
CONCEPT 4.3 A few chemical groups are key to molecular function
5 The Structure and Function of Large Biological Molecules
The Molecules of Life
CONCEPT 5.1 Macromolecules are polymers, built from monomers
CONCEPT 5.2 Carbohydrates serve as fuel and building material
CONCEPT 5.3 Lipids are a diverse group of hydrophobic molecules
CONCEPT 5.4 Proteins include a diversity of structures, resulting in a wide range of functions
CONCEPT 5.5 Nucleic acids store, transmit, and help express hereditary information
CONCEPT 5.6 Genomics and proteomics have transformed biological inquiry and applications
UNIT 2 THE CELL
6 A Tour of the Cell
The Fundamental Units of Life
CONCEPT 6.1 Biologists use microscopes and biochemistry to study cells
CONCEPT 6.2 Eukaryotic cells have internal membranes that compartmentalize their functions
CONCEPT 6.3 The eukaryotic cell’s genetic instructions are housed in the nucleus and carried out by the ribosomes
CONCEPT 6.4 The endomembrane system regulates protein traffic and performs metabolic functions
CONCEPT 6.5 Mitochondria and chloroplasts change energy from one form to another
CONCEPT 6.6 The cytoskeleton is a network of fibers that organizes structures and activities in the cell
CONCEPT 6.7 Extracellular components and connections between cells help coordinate cellular activities
CONCEPT 6.8 A cell is greater than the sum of its parts
7 Membrane Structure and Function
Life at the Edge
CONCEPT 7.1 Cellular membranes are fluid mosaics of lipids and proteins
CONCEPT 7.2 Membrane structure results in selective permeability
CONCEPT 7.3 Passive transport is diffusion of a substance across a membrane with no energy investment
CONCEPT 7.4 Active transport uses energy to move solutes against their gradients
CONCEPT 7.5 Bulk transport across the plasma membrane occurs by exocytosis and endocytosis
8 An Introduction to Metabolism
The Energy of Life
CONCEPT 8.1 An organism’s metabolism transforms matter and energy, subject to the laws of thermodynamics
CONCEPT 8.2 The free-energy change of a reaction tells us whether or not the reaction occurs spontaneously
CONCEPT 8.3 ATP powers cellular work by coupling exergonic reactions to endergonic reactions
CONCEPT 8.4 Enzymes speed up metabolic reactions by lowering energy barriers
CONCEPT 8.5 Regulation of enzyme activity helps control metabolism
9 Cellular Respiration and Fermentation
Life Is Work
CONCEPT 9.1 Catabolic pathways yield energy by oxidizing organic fuels
CONCEPT 9.2 Glycolysis harvests chemical energy by oxidizing glucose to pyruvate
CONCEPT 9.3 After pyruvate is oxidized, the citric acid cycle completes the energy-yielding oxidation of organic molecules
CONCEPT 9.4 During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis
CONCEPT 9.5 Fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen
CONCEPT 9.6 Glycolysis and the citric acid cycle connect to many other metabolic pathways
10 Photosynthesis
The Process That Feeds the Biosphere
CONCEPT 10.1 Photosynthesis converts light energy to the chemical energy of food
CONCEPT 10.2 The light reactions convert solar energy to the chemical energy of ATP and NADPH
CONCEPT 10.3 The Calvin cycle uses the chemical energy of ATP and NADPH to reduce CO2 to sugar
CONCEPT 10.4 Alternative mechanisms of carbon fixation have evolved in hot, arid climates
CONCEPT 10.5Life depends on photosynthesis
11 Cell Communication
Cellular Messaging
CONCEPT 11.1 External signals are converted to responses within the cell
CONCEPT 11.2 Reception: A signaling molecule binds to a receptor protein, causing it to change shape
CONCEPT 11.3 Transduction: Cascades of molecular interactions relay signals from receptors to target molecules in the cell
CONCEPT 11.4 Response: Cell signaling leads to regulation of transcription or cytoplasmic activities
CONCEPT 11.5 Apoptosis integrates multiple cell-signaling pathways
12 The Cell Cycle
The Key Roles of Cell Division
CONCEPT 12.1 Most cell division results in genetically identical daughter cells
CONCEPT 12.2 The mitotic phase alternates with interphase in the cell cycle
CONCEPT 12.3 The eukaryotic cell cycle is regulated by a molecular control system
UNIT 3 GENETICS
13 Meiosis and Sexual Life Cycles
Variations on a Theme
CONCEPT 13.1 Offspring acquire genes from parents by inheriting chromosomes
CONCEPT 13.2 Fertilization and meiosis alternate in sexual life cycles
CONCEPT 13.3 Meiosis reduces the number of chromosome sets from diploid to haploid
CONCEPT 13.4 Genetic variation produced in sexual life cycles contributes to evolution
14 Mendel and the Gene Idea
Drawing from the Deck of Genes
CONCEPT 14.1 Mendel used the scientific approach to identify two laws of inheritance
CONCEPT 14.2 Probability laws govern Mendelian inheritance
CONCEPT 14.3 Inheritance patterns are often more complex than predicted by simple Mendelian genetics
CONCEPT 14.4 Many human traits follow Mendelian patterns of inheritance
15 The Chromosomal Basis of Inheritance
Locating Genes Along Chromosomes
CONCEPT 15.1 Morgan showed that Mendelian inheritance has its physical basis in the behavior of chromosomes: scientific inquiry
CONCEPT 15.2 Sex-linked genes exhibit unique patterns of inheritance
CONCEPT 15.3 Linked genes tend to be inherited together because they are located near each other on the same chromosome
CONCEPT 15.4 Alterations of chromosome number or structure cause some genetic disorders
CONCEPT 15.5 Some inheritance patterns are exceptions to standard Mendelian inheritance
16 The Molecular Basis of Inheritance
Life’s Operating Instructions
CONCEPT 16.1 DNA is the genetic material
CONCEPT 16.2 Many proteins work together in DNA replication and repair
CONCEPT 16.3 A chromosome consists of a DNA molecule packed together with proteins
17 Gene Expression: From Gene to Protein
The Flow of Genetic Information
CONCEPT 17.1 Genes specify proteins via transcription and translation
CONCEPT 17.2 Transcription is the DNA-directed synthesis of RNA: a closer look
CONCEPT 17.3 Eukaryotic cells modify RNA after transcription
CONCEPT 17.4 Translation is the RNA-directed synthesis of a polypeptide: a closer look
CONCEPT 17.5 Mutations of one or a few nucleotides can affect protein structure and function
18 Regulation of Gene Expression
Beauty in the Eye of the Beholder
CONCEPT 18.1 Bacteria often respond to environmental change by regulating transcription
CONCEPT 18.2 Eukaryotic gene expression is regulated at many stages
CONCEPT 18.3 Noncoding RNAs play multiple roles in controlling gene expression
CONCEPT 18.4 A program of differential gene expression leads to the different cell types in a multicellular organism
CONCEPT 18.5 Cancer results from genetic changes that affect cell cycle control
19 Viruses
A Borrowed Life
CONCEPT 19.1 A virus consists of a nucleic acid surrounded by a protein coat
CONCEPT 19.2 Viruses replicate only in host cells
CONCEPT 19.3 Viruses and prions are formidable pathogens in animals and plants
20 DNA Tools and Biotechnology
The DNA Toolbox
CONCEPT 20.1 DNA sequencing and DNA cloning are valuable tools for genetic engineering and biological inquiry
CONCEPT 20.2 Biologists use DNA technology to study gene expression and function
CONCEPT 20.3 Cloned organisms and stem cells are useful for basic research and other applications
CONCEPT 20.4 The practical applications of DNA-based biotechnology affect our lives in many ways
21 Genomes and Their Evolution
Reading the Leaves from the Tree of Life
CONCEPT 21.1 The Human Genome Project fostered development of faster, less expensive sequencing techniques
CONCEPT 21.2 Scientists use bioinformatics to analyze genomes and their functions
CONCEPT 21.3 Genomes vary in size, number of genes, and gene density
CONCEPT 21.4 Multicellular eukaryotes have a lot of noncoding DNA and many multigene families
CONCEPT 21.5 Duplication, rearrangement, and mutation of DNA contribute to genome evolution
CONCEPT 21.6 Comparing genome sequences provides clues to evolution and development
UNIT 4 MECHANISMS OF EVOLUTION
22 Descent with Modification: A Darwinian View of Life
Endless Forms Most Beautiful
CONCEPT 22.1 The Darwinian revolution challenged traditional views of a young Earth inhabited by unchanging species
CONCEPT 22.2 Descent with modification by natural selection explains the adaptations of organisms and the unity and diversity of life
CONCEPT 22.3 Evolution is supported by an overwhelming amount of scientific evidence
23 The Evolution of Populations
The Smallest Unit of Evolution
CONCEPT 23.1 Genetic variation makes evolution possible
CONCEPT 23.2 The Hardy-Weinberg equation can be used to test whether a population is evolving
CONCEPT 23.3 Natural selection, genetic drift, and gene flow can alter allele frequencies in a population
CONCEPT 23.4 Natural selection is the only mechanism that consistently causes adaptive evolution
24 The Origin of Species
That “Mystery of Mysteries”
CONCEPT 24.1 The biological species concept emphasizes reproductive isolation
CONCEPT 24.2 Speciation can take place with or without geographic separation
CONCEPT 24.3 Hybrid zones reveal factors that cause reproductive isolation
CONCEPT 24.4 Speciation can occur rapidly or slowly and can result from changes in few or many genes
25 The History of Life on Earth
A Surprise in the Desert
CONCEPT 25.1 Conditions on early Earth made the origin of life possible
CONCEPT 25.2 The fossil record documents the history of life
CONCEPT 25.3 Key events in life’s history include the origins of unicellular and multicellular organisms and the colonization of land
CONCEPT 25.4 The rise and fall of groups of organisms reflect differences in speciation and extinction rates
CONCEPT 25.5 Major changes in body form can result from changes in the sequences and regulation of developmental genes
CONCEPT 25.6 Evolution is not goal oriented
UNIT 5 THE EVOLUTIONARY HISTORY OF BIOLOGICAL DIVERSITY
26 Phylogeny and the Tree of Life
Investigating the Tree of Life
CONCEPT 26.1 Phylogenies show evolutionary relationships
CONCEPT 26.2 Phylogenies are inferred from morphological and molecular data
CONCEPT 26.3 Shared characters are used to construct phylogenetic trees
CONCEPT 26.4 An organism’s evolutionary history is documented in its genome
CONCEPT 26.5 Molecular clocks help track evolutionary time
CONCEPT 26.6 Our understanding of the tree of life continues to change based on new data
27 Bacteria and Archaea
Masters of Adaptation
CONCEPT 27.1 Structural and functional adaptations contribute to prokaryotic success
CONCEPT 27.2 Rapid reproduction, mutation, and genetic recombination promote genetic diversity in prokaryotes
CONCEPT 27.3 Diverse nutritional and metabolic adaptations have evolved in prokaryotes
CONCEPT 27.4 Prokaryotes have radiated into a diverse set of lineages
CONCEPT 27.5 Prokaryotes play crucial roles in the biosphere
CONCEPT 27.6 Prokaryotes have both beneficial and harmful impacts on humans
28 Protists
Living Small
CONCEPT 28.1 Most eukaryotes are single-celled organisms
CONCEPT 28.2 Excavates include protists with modified mitochondria and protists with unique flagella
CONCEPT 28.3 SAR is a highly diverse group of protists defined by DNA similarities
CONCEPT 28.4 Red algae and green algae are the closest relatives of land plants
CONCEPT 28.5 Unikonts include protists that are closely related to fungi and animals
CONCEPT 28.6 Protists play key roles in ecological communities
29 Plant Diversity I: How Plants Colonized Land
The Greening of Earth
CONCEPT 29.1 Plants evolved from green algae
CONCEPT 29.2 Mosses and other nonvascular plants have life cycles dominated by gametophytes
CONCEPT 29.3 Ferns and other seedless vascular plants were the first plants to grow tall
30 Plant Diversity II: The Evolution of Seed Plants
Transforming the World
CONCEPT 30.1 Seeds and pollen grains are key adaptations for life on land
CONCEPT 30.2 Gymnosperms bear “naked” seeds, typically on cones
CONCEPT 30.3 The reproductive adaptations of angiosperms include flowers and fruits
CONCEPT 30.4 Human welfare depends on seed plants
31 Fungi
Mighty Mushrooms
CONCEPT 31.1 Fungi are heterotrophs that feed by absorption
CONCEPT 31.2 Fungi produce spores through sexual or asexual life cycles
CONCEPT 31.3 The ancestor of fungi was an aquatic, single-celled, flagellated protist
CONCEPT 31.4 Fungi have radiated into a diverse set of lineages
CONCEPT 31.5 Fungi play key roles in nutrient cycling, ecological interactions, and human welfare
32 An Overview of Animal Diversity
A Kingdom of Consumers
CONCEPT 32.1 Animals are multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers
CONCEPT 32.2 The history of animals spans more than half a billion years
CONCEPT 32.3 Animals can be characterized by “body plans”
CONCEPT 32.4 Views of animal phylogeny continue to be shaped by new molecular and morphological data
33 An Introduction to Invertebrates
A Dragon Without a Backbone
CONCEPT 33.1 Sponges are basal animals that lack tissues
CONCEPT 33.2 Cnidarians are an ancient phylum of eumetazoans
CONCEPT 33.3 Lophotrochozoans, a clade identified by molecular data, have the widest range of animal body forms
CONCEPT 33.4 Ecdysozoans are the most species-rich animal group
CONCEPT 33.5 Echinoderms and chordates are deuterostomes
34 The Origin and Evolution of Vertebrates
Half a Billion Years of Backbones
CONCEPT 34.1 Chordates have a notochord and a dorsal, hollow nerve cord
CONCEPT 34.2 Vertebrates are chordates that have a backbone
CONCEPT 34.3 Gnathostomes are vertebrates that have jaws
CONCEPT 34.4 Tetrapods are gnathostomes that have limbs
CONCEPT 34.5 Amniotes are tetrapods that have a terrestrially adapted egg
CONCEPT 34.6 Mammals are amniotes that have hair and produce milk
CONCEPT 34.7 Humans are mammals that have a large brain and bipedal locomotion
UNIT 6 PLANT FORM AND FUNCTION
35 Vascular Plant Structure, Growth, and Development
Are Plants Computers?
CONCEPT 35.1 Plants have a hierarchical organization consisting of organs, tissues, and cells
CONCEPT 35.2 Different meristems generate new cells for primary and secondary growth
CONCEPT 35.3 Primary growth lengthens roots and shoots
CONCEPT 35.4 Secondary growth increases the diameter of stems and roots in woody plants
CONCEPT 35.5 Growth, morphogenesis, and cell differentiation produce the plant body
36 Resource Acquisition and Transport in Vascular Plants
A Whole Lot of Shaking Going On
CONCEPT 36.1 Adaptations for acquiring resources were key steps in the evolution of vascular plants
CONCEPT 36.2 Different mechanisms transport substances over short or long distances
CONCEPT 36.3 Transpiration drives the transport of water and minerals from roots to shoots via the xylem
CONCEPT 36.4 The rate of transpiration is regulated by stomata
CONCEPT 36.5 Sugars are transported from sources to sinks via the phloem
CONCEPT 36.6 The symplast is highly dynamic
37 Soil and Plant Nutrition
The Corkscrew Carnivore
CONCEPT 37.1 Soil contains a living, complex ecosystem
CONCEPT 37.2 Plant roots absorb essential elements from the soil
CONCEPT 37.3 Plant nutrition often involves relationships with other organisms
38 Angiosperm Reproduction and Biotechnology
Flowers of Deceit
CONCEPT 38.1 Flowers, double fertilization, and fruits are key features of the angiosperm life cycle
CONCEPT 38.2 Flowering plants reproduce sexually, asexually, or both
CONCEPT 38.3 People modify crops by breeding and genetic engineering
39 Plant Responses to Internal and External Signals
Stimuli and a Stationary Life
CONCEPT 39.1 Signal transduction pathways link signal reception to response
CONCEPT 39.2 Plant hormones help coordinate growth, development, and responses to stimuli
CONCEPT 39.3 Responses to light are critical for plant success
CONCEPT 39.4 Plants respond to a wide variety of stimuli other than light
CONCEPT 39.5 Plants respond to attacks by pathogens and herbivores
UNIT 7 ANIMAL FORM AND FUNCTION
40 Basic Principles of Animal Form and Function
Diverse Forms, Common Challenges
CONCEPT 40.1 Animal form and function are correlated at all levels of organization
CONCEPT 40.2 Feedback control maintains the internal environment in many animals
CONCEPT 40.3 Homeostatic processes for thermoregulation involve form, function, and behavior
CONCEPT 40.4 Energy requirements are related to animal size, activity, and environment
41 Animal Nutrition
The Need to Feed
CONCEPT 41.1 An animal’s diet must supply chemical energy, organic building blocks, and essential nutrients
CONCEPT 41.2 Food processing involves ingestion, digestion, absorption, and elimination
CONCEPT 41.3 Organs specialized for sequential stages of food processing form the mammalian digestive system
CONCEPT 41.4 Evolutionary adaptations of vertebrate digestive systems correlate with diet
CONCEPT 41.5 Feedback circuits regulate digestion, energy storage, and appetite
42 Circulation and Gas Exchange
Trading Places
CONCEPT 42.1 Circulatory systems link exchange surfaces with cells throughout the body
CONCEPT 42.2 Coordinated cycles of heart contraction drive double circulation in mammals
CONCEPT 42.3 Patterns of blood pressure and flow reflect the structure and arrangement of blood vessels
CONCEPT 42.4 Blood components function in exchange, transport, and defense
CONCEPT 42.5 Gas exchange occurs across specialized respiratory surfaces
CONCEPT 42.6 Breathing ventilates the lungs
CONCEPT 42.7 Adaptations for gas exchange include pigments that bind and transport gases
43 The Immune System
Recognition and Response
CONCEPT 43.1 In innate immunity, recognition and response rely on traits common to groups of pathogens
CONCEPT 43.2 In adaptive immunity, receptors provide pathogen-specific recognition
CONCEPT 43.3 Adaptive immunity defends against infection of body fluids and body cells
CONCEPT 43.4 Disruptions in immune system function can elicit or exacerbate disease
44 Osmoregulation and Excretion
A Balancing Act
CONCEPT 44.1 Osmoregulation balances the uptake and loss of water and solutes
CONCEPT 44.2 An animal’s nitrogenous wastes reflect its phylogeny and habitat
CONCEPT 44.3 Diverse excretory systems are variations on a tubular theme
CONCEPT 44.4 The nephron is organized for stepwise processing of blood filtrate
CONCEPT 44.5 Hormonal circuits link kidney function, water balance, and blood pressure
45 Hormones and the Endocrine System
The Body’s Long-Distance Regulators
CONCEPT 45.1 Hormones and other signaling molecules bind to target receptors, triggering specific response pathways
CONCEPT 45.2 Feedback regulation and coordination with the nervous system are common in hormone pathways
CONCEPT 45.3 Endocrine glands respond to diverse stimuli in regulating homeostasis, development, and behavior
46 Animal Reproduction
Let Me Count the Ways
CONCEPT 46.1 Both asexual and sexual reproduction occur in the animal kingdom
CONCEPT 46.2 Fertilization depends on mechanisms that bring together sperm and eggs of the same species
CONCEPT 46.3 Reproductive organs produce and transport gametes
CONCEPT 46.4 The interplay of tropic and sex hormones regulates mammalian reproduction
CONCEPT 46.5 In placental mammals, an embryo develops fully within the mother’s uterus
47 Animal Development
A Body-Building Plan
CONCEPT 47.1 Fertilization and cleavage initiate embryonic development
CONCEPT 47.2 Morphogenesis in animals involves specific changes in cell shape, position, and survival
CONCEPT 47.3 Cytoplasmic determinants and inductive signals regulate cell fate
48 Neurons, Synapses, and Signaling
Lines of Communication
CONCEPT 48.1 Neuron structure and organization reflect function in information transfer
CONCEPT 48.2 Ion pumps and ion channels establish the resting potential of a neuron
CONCEPT 48.3 Action potentials are the signals conducted by axons
CONCEPT 48.4 Neurons communicate with other cells at synapses
49 Nervous Systems
Command and Control Center
CONCEPT 49.1 Nervous systems consist of circuits of neurons and supporting cells
CONCEPT 49.2 The vertebrate brain is regionally specialized
CONCEPT 49.3 The cerebral cortex controls voluntary movement and cognitive functions
CONCEPT 49.4 Changes in synaptic connections underlie memory and learning
CONCEPT 49.5 Many nervous system disorders can be explained in molecular terms
50 Sensory and Motor Mechanisms
Sense and Sensibility
CONCEPT 50.1 Sensory receptors transduce stimulus energy and transmit signals to the central nervous system
CONCEPT 50.2 In hearing and equilibrium, mechanoreceptors detect moving fluid or settling particles
CONCEPT 50.3 The diverse visual receptors of animals depend on light-absorbing pigments
CONCEPT 50.4 The senses of taste and smell rely on similar sets of sensory receptors
CONCEPT 50.5 The physical interaction of protein filaments is required for muscle function
CONCEPT 50.6 Skeletal systems transform muscle contraction into locomotion
51 Animal Behavior
The How and Why of Animal Activity
CONCEPT 51.1 Discrete sensory inputs can stimulate both simple and complex behaviors
CONCEPT 51.2 Learning establishes specific links between experience and behavior
CONCEPT 51.3 Selection for individual survival and reproductive success can explain diverse behaviors
CONCEPT 51.4 Genetic analyses and the concept of inclusive fitness provide a basis for studying the evolution of behavior
UNIT 8 ECOLOGY
52 An Introduction to Ecology and the Biosphere
Discovering Ecology
CONCEPT 52.1 Earth’s climate varies by latitude and season and is changing rapidly
CONCEPT 52.2 The distribution of terrestrial biomes is controlled by climate and disturbance
CONCEPT 52.3 Aquatic biomes are diverse and dynamic systems that cover most of Earth
CONCEPT 52.4 Interactions between organisms and the environment limit the distribution of species
CONCEPT 52.5Ecological change and evolution affect one another over long and short periods of time
53 Population Ecology
Turtle Tracks
CONCEPT 53.1 Biotic and abiotic factors affectpopulation density, dispersion, and demographics
CONCEPT 53.2 The exponential model describes population growth in an idealized, unlimited environment
CONCEPT 53.3 The logistic model describes how a population grows more slowly as it nears its carrying capacity
CONCEPT 53.4 Life history traits are products of natural selection
CONCEPT 53.5 Density-dependent factors regulate population growth
CONCEPT 53.6 The human population is no longer growing exponentially but is still increasing rapidly
54 Community Ecology
Communities in Motion
CONCEPT 54.1 Community interactions are classified by whether they help, harm, or have no effect on the species involved
CONCEPT 54.2 Diversity and trophic structure characterize biological communities
CONCEPT 54.3 Disturbance influences species diversity and composition
CONCEPT 54.4 Biogeographic factors affect community diversity
CONCEPT 54.5 Pathogens alter community structure locally and globally
55 Ecosystems and Restoration Ecology
Transformed to Tundra
CONCEPT 55.1 Physical laws govern energy flow and chemical cycling in ecosystems
CONCEPT 55.2 Energy and other limiting factors control primary production in ecosystems
CONCEPT 55.3 Energy transfer between trophic levels is typically only 10% efficient
CONCEPT 55.4 Biological and geochemical processes cycle nutrients and water in ecosystems
CONCEPT 55.5 Restoration ecologists return degraded ecosystems to a more natural state
56 Conservation Biology and Global Change
Psychedelic Treasure
CONCEPT 56.1 Human activities threaten Earth’s biodiversity
CONCEPT 56.2 Population conservation focuses on population size, genetic diversity, and critical habitat
CONCEPT 56.3 Landscape and regional conservation help sustain biodiversity
CONCEPT 56.4 Earth is changing rapidly as a result of human actions
CONCEPT 56.5 Sustainable development can improve human lives while conserving biodiversity
