6 The biosphere Tissues Ecosystems Organs and organ systems Communities Figure 1.4The biosphereTissuesEcosystemsOrgans andorgan systemsCommunitiesFigure 1.4 Exploring: Levels of Biological OrganizationCellsOrganellesOrganismsAtomsMoleculesPopulations
9 Cycling of chemical nutrients Figure 1.5SunlightLeaves absorb light energy from the sun.Leaves take in carbon dioxide from the air and release oxygen.CO2O2Cycling of chemical nutrientsFigure 1.5 Interactions of an African acacia tree with other organisms and the physical environment.Animals eatleaves and fruitfrom the tree.Leaves fall to the ground and are decomposed by organisms that return minerals to the soil.Water and minerals in the soil are taken up by the tree through its roots.
11 Figure 1.6 Energy flow in an ecosystem. SunlightHeatWhen energy is used to do work, some energy is converted to thermal energy, which is lost as heat.Producers absorb light energy and transform it into chemical energy.An animal’s muscle cells convert chemical energy from food to kinetic energy, the energy of motion.ChemicalenergyA plant’s cells use chemical energy to do work such as growing new leaves.Chemical energy in food is transferred from plants to consumers.Figure 1.6 Energy flow in an ecosystem.(a) Energy flow from sunlight to producers to consumers(b) Using energy to do work
26 Ursus americanus (American black bear) Figure 1.14SpeciesGenusFamilyOrderClassPhylumKingdomDomainUrsus americanus (American black bear)UrsusUrsidaeCarnivoraMammaliaChordataFigure 1.14 Classifying life.AnimaliaEukarya
30 15 m 5 m 0.1 m Cilia of Paramecium Cilia of windpipe cells Figure 1.1615 m5 mCilia of ParameciumCilia of windpipe cellsFigure 1.16 An example of unity underlying the diversity of life: the architecture of cilia in eukaryotes.0.1 mCross section of a cilium, as viewed with an electron microscope
38 Population with varied inherited traits 2 Figure 1.201Population with varied inherited traits2Elimination of individuals with certain traits3Reproduction of survivors4Increasing frequency of traits that enhance survival and reproductive successFigure 1.20 Natural selection.