Essential Questions: What are the characteristics of life?

1. Georgia Performance Standards:Students will understand and identify the characteristics of living organisms. Essential Questions: What are the characteristics of life?

2. 1-1 Studying Life • The word biology means the study of life. • Biology is the science that seeks to understand the living world. • A biologist is someone who uses a scientific method to study living things.

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

4. Living things, or organisms, are made up of small, self-contained units called cells. A cell is a collection of living matter enclosed by a barrier that separates the cell from its surroundings. Cells are the smallest units of an organism that can be considered alive. grow, respond to their surroundings, and reproduce. complex and highly organized. Unicellular or multicellular Cells

5. All organisms produce new organisms through a process called reproduction. There are two basic kinds of reproduction: sexual and asexual. Many multicellular organisms reproduce sexually. In sexual reproduction, two cells from different parents unite to produce the first cell of the new organism. Offspring and parents have different genetic info. In asexual reproduction, the new organism has a single parent. Can divided in half to form 2 new organisms Can undergo budding where a portion of an organism splits off to form a new organism. Offspring and parents have identical genetic info. Reproduction

6. Based on a Genetic Code • Flies produce flies, dogs produce dogs, and seeds from maple trees produce maple trees. • Biologists now know that the directions for inheritance are carried by a molecule called deoxyribonucleic acid, or DNA. • With minor exceptions, the DNA genetic code determines the inherited traits of every organism on Earth.

7. Growth and Development • Each type of organism has a distinctive life cycle—a particular pattern of growth and change that occurs over the organism’s lifetime. • The life cycle (Growth) of many kinds of multicellular organisms involves a process called development. • During this process, the cells in an organism not only increase in number but also become different, or differentiate.

8. Need for Materials and Energy  • An animal gets the materials and energy it needs by eating smaller animals. • The combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes is called metabolism. • All organisms take in selected materials that they need from their surroundings, or environment, but the way they obtain energy varies.

9. Maintaining Internal Balance  • The process by which organisms keep their internal conditions relatively stable is called homeostasis. • Homeostasis is constantly being threatened by changes in the environment • changing temperatures and light.

10. Evolution • A population of any given type of organism can evolve, or change over time. • Over hundreds of thousands or even millions of years, the changes in a population can be dramatic. • The ability of a group of organisms to evolve over time is extremely important for survival in a world that is always changing.

11. Levels of Organization of Life • Molecules • Cells • Organisms • Populations of a single organism, • Communities of populations living in the same area • Biosphere.

13. Checkpoint Questions • Describe five characteristics of living things. • What topics might biologists study at the community level of organization? 3. Compare sexual reproduction and asexual reproduction. 4. What biological process includes chemical reactions that break down materials? 5. What happens to an organism if its homeostasis is disrupted and not restored? 6. Try to think of a nonliving thing that satisfies each characteristic of living things. Does any nonliving thing have all the characteristics of life?

14. Dirty Science Lab • Your Objective is to see if you can tell by looking carefully with a microscope whether something in the soil is now alive, is dead but once alive, or was never alive.

15. Observing Life • Crayfish Lab

16. Homework: • Complete Chapter 1 guided reading