Figure 1.3 Some properties of life. Order Response to the environment Evolutionary adaptation Reproduction Figure 1.3 Some properties of life. Regulation Energy processing Growth and development

The biosphere Tissues Ecosystems Organs and organ systems Communities Figure 1.4 Exploring: Levels of Biological Organization Cells Organelles Organisms Atoms Molecules Populations

Cycling of chemical nutrients Sunlight Leaves absorb light energy from the sun. Leaves take in carbon dioxide from the air and release oxygen. CO2 O2 Cycling of chemical nutrients Figure 1.5 Interactions of an African acacia tree with other organisms and the physical environment. Animals eat leaves and fruit from 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.

Figure 1.6 Energy flow in an ecosystem. Sunlight Heat When 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. Chemical energy A 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

(a) Wings (b) Wing bones Figure 1.7 Form fits function in a gull’s wing. (b) Wing bones

Nucleus (membrane- enclosed) Prokaryotic cell Eukaryotic cell DNA (no nucleus) Membrane Membrane Cytoplasm Figure 1.8 Contrasting eukaryotic and prokaryotic cells in size and complexity. Nucleus (membrane- enclosed) Membrane- enclosed organelles DNA (throughout nucleus) 1 m

Fertilized egg with DNA from both parents Sperm cell Nuclei containing DNA Fertilized egg with DNA from both parents Embryo’s cells with copies of inherited DNA Egg cell Figure 1.10 Inherited DNA directs development of an organism. Offspring with traits inherited from both parents

(b) Single strand of DNA Nucleus A C DNA Nucleotide T A T T Cell A C C G T Figure 1.11 DNA: The genetic material. A G T A (a) DNA double helix (b) Single strand of DNA

Figure 1.13 Regulation by feedback mechanisms. Negative feedback Enzyme 1 B D Enzyme 2 Excess D blocks a step. D D C C Enzyme 3 D (a) Negative feedback W Enzyme 4 Figure 1.13 Regulation by feedback mechanisms. X Positive feedback  Enzyme 5 Excess Z stimulates a step. Z Y Z Z Enzyme 6 Z (b) Positive feedback

Ursus americanus (American black bear) Species Genus Family Order Class Phylum Kingdom Domain Ursus americanus (American black bear) Ursus Ursidae Carnivora Mammalia Figure 1.14 Classifying life. Chordata Animalia Eukarya

(a) Domain Bacteria (b) Domain Archaea (c) Domain Eukarya 2 m 2 m Kingdom Animalia 100 m Figure 1.15 The three domains of life. Kingdom Plantae Protists Kingdom Fungi

15 m 5 m 0.1 m Cilia of Paramecium Cilia of windpipe cells Figure 1.16 An example of unity underlying the diversity of life: the architecture of cilia in eukaryotes. 0.1 m Cross section of a cilium, as viewed with an electron microscope

Population with varied inherited traits 2 1 Population with varied inherited traits 2 Elimination of individuals with certain traits 3 Reproduction of survivors 4 Increasing frequency of traits that enhance survival and reproductive success Figure 1.20 Natural selection.

Cactus-flower- eaters Green warbler finch Certhidea olivacea Warbler finches Insect-eaters COMMON ANCESTOR Gray warbler finch Certhidea fusca Sharp-beaked ground finch Geospiza difficilis Seed-eater Vegetarian finch Platyspiza crassirostris Bud-eater Mangrove finch Cactospiza heliobates Woodpecker finch Cactospiza pallida Tree finches Insect-eaters Medium tree finch Camarhynchus pauper Large tree finch Camarhynchus psittacula Small tree finch Camarhynchus parvulus Large cactus ground finch Geospiza conirostris Figure 1.22 Descent with modification: adaptive radiation of finches on the Galápagos Islands. Cactus-flower- eaters Cactus ground finch Geospiza scandens Ground finches Seed-eaters Small ground finch Geospiza fuliginosa Medium ground finch Geospiza fortis Large ground finch Geospiza magnirostris

Figure 1.24 A campground example of hypothesis-based inquiry. Observations Question Hypothesis #1: Dead batteries Hypothesis #2: Burnt-out bulb Prediction: Replacing batteries will fix problem Prediction: Replacing bulb will fix problem Figure 1.24 A campground example of hypothesis-based inquiry. Test of prediction Test of prediction Test falsifies hypothesis Test does not falsify hypothesis