Chapter 1 Exploring Life Hierarchy levels of biological

Chapter 1: Exploring Life • Hierarchy, levels of biological structure • Properties of life (at least 7) • Evolution, Unity and Diversity • Scientific Method

Life’s Hierarchical Order n n n n n Biosphere Ecosystem Community Population Organism Organs Tissues Cells Atoms Emergent properties

Biosphere: all the environments of Earth that support life n Ecosystem: All the living and nonliving components of a particular environment n Community: All the living organisms in an ecosystem n Population: an interacting group of individuals of one species n Organism: An individual living entity n

Living organisms and their environments form interconnecting webs n n n Producers-photosynthetic organisms-use energy from the sun to produce food Consumers are ultimately dependent on producers for food Decomposers break down dead organic material, which is recycled

n The dynamics of an ecosystem include two major processes: The cycling of chemical nutrients n The one-way flow of energy, entering as sunlight and leaving as heat n

LE 1 -2 Sun Air Inflow of light energy O 2 CO 2 Chemical energy Producers Cycling of chemical nutrients Consumers Decomposers H 2 O cycling Ecosystem Soil Loss of heat energy

n Cells are the structural and functional units of life n Cells perform all functions necessary for life Regulate their internal environment n Take in and use energy n Respond to the local environment n Develop and maintain their complex organization n Divide to form new cells n

n Two basic types of cells: prokaryotes and eukaryotes Prokaryotes are smaller and less complex than eukaryotes and lack a nucleus and other membrane bound organelles n Eukaryotes are generally larger and more complex and contain a nucleus and other organelles n

EVOLUTION, UNITY, AND DIVERSITY n The unity of life: All forms of life have common features

Characteristics of Living Things Characteristic Examples Living things are made up of units called cells. Living things reproduce. Living things obtain and use materials and energy (TAKE IN NUTRIENTS) Many microorganisms consist of only a single cell. Animals and trees are multicellular. Maple trees reproduce sexually. A hydra can reproduce asexually by budding. (SEED TO PLANT) Flies produce flies. Dogs produce dogs. Seeds from maple trees produce maple trees. Flies begin life as eggs, then become maggots, and then become adult flies. (Caterpillar to Butterfly) Plants obtain their energy from sunlight. Animals obtain their energy from the food they eat. Living things respond to their environment Leaves and stems of plants grow toward light. Living things maintain a stable internal environment. Despite changes in the temperature of the environment, a robin maintains a constant body temperature. Taken as a group, living things change over time. (Evolve) Plants that live in the desert survive because they have become adapted to the conditions of the desert. Living things are based on a universal genetic code. Living things grow and develop.

n The diversity of life can be arranged into three domains n n Scientists have identified about 1. 8 million species-particular types of organisms Taxonomy classifies species into a hierarchy of increasingly broad groups

Taxonomy

Domains of Life (3) n 1. Bacteria n n 2. Archaea n n (prokaryotes, most ancient) (prokaryotes, extreme ) 3. Eukarya n (eukaryotes = protists, plants, animals, fungi)

n Evolution explains the unity and diversity of life n Charles Darwin proposed theory of evolution by natural selection Species evolved from ancestors through "descent with modification" n Natural selection occurs as heritable variations are exposed to environmental factors that favor the reproductive success of some individuals over others n n The product of natural selection is adaptation

LE 1 -6 b Population with varied inherited traits Elimination of individuals with certain traits Reproduction of survivors

THE PROCESS OF SCIENCE n Scientists use two main approaches to learn about nature n Discovery science n n Primarily describes nature through verifiable observations and measurements Hypothesis-driven science Attempts to explain nature by studying questions drawn from observations made during "discovery science" n Hypothesis: a tentative answer to a problem or question that is being asked n

Steps in the Scientific Method n n n Observation Hypothesis Experiment Data/Results Conclusion

What are the main components of conducting an experiment?

Think about this… n Let’s say that Brad has a pimple. He wonders what will get rid of it. He’s heard that putting toothpaste on the zit will get rid of it. He’s also heard that lemon juice will get rid of it. He decides to rub his face with lemon juice and toothpaste. The next morning his pimple is gone. But which thing cured him? The toothpaste or the lemon juice?

The Answer? n n How many of you think it was the toothpaste? Raise your hand. How many of you think it was the lemon juice? Raise your hand. The truth is…. THERE IS NO WAY FOR YOU TO KNOW FOR SURE!!!

Every Good Experiment Has Three Things! 1) 2) 3) Independent variable Dependent variable Control So What Are These?

Variable Change Able to Variable: A factor that can change in an experiment. Every experiment has two – one is the cause, the other is the effect.

Cause and Effect n Does crushing a sugar cube effect the rate at which the sugar dissolves in the water? What is the cause and what is the effect?

Crushing the sugar cube is what we predict will be the cause. Crushing the sugar cube will effect how long it takes to dissolve. This is called the Independent Variable The time it takes to dissolve is what we will see the effect on. This is called the Dependent Variable

Independent variable The variable being tested in an experiment. (“I”choose)

Dependent variable The variable we predict will be effected. (‘Depends on what I choose’)

Experiment Title: Does the age of a person gets married effect their chances of getting a divorce? IV- Age DV- Chances of divorce Experiment Title: Is there are relationship between the weather and how students behave? IV- weather DV- behavior

What is the Purpose of a Control? n Controls are NOT being tested n Controls are used for COMPARISON

Practice with Controls n Does fertilizer affect plant height? n Independent Variable: FERTILIZER n Dependent Variable: PLANT HEIGHT How can we be sure that the fertilizer is effecting the plant height? n Control: A plant that does not contain fertilizer

Remember: To be a Valid Experiment: Two groups are required --the control & experimental groups n There should be only one variable n

THE MISSION… n Ms. Nakamura is in need of a group of students who will help her create a garden. Unfortunately she does not have that much knowledge in the germination of seeds and has asked the help of her brilliant AP Biology students to help her decide what seeds to use and what time of factors might influence the seeds’ maturation/growth.