1.3 Studying Life Life can be found underwater, in the Antarctic, and in the desert. Biology is the science that seeks to understand the living world. Bios = life, logos = study of Use scientific method to study living things

Characteristics of Living Things Living things are made up of units called cells. Living things reproduce. Living things are based on a universal genetic code. Living things grow and develop. Living things obtain and use materials and energy. Living things respond to their environment. Living things maintain a stable internal environment. Taken as a group, living things change over time.

Made Up of 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 are still alive. Organisms can be unicellular (one-celled) or multicellular (many-celled). Humans have 85 different cell types.

Reproduction There are two types of reproduction: Sexual Reproduction Cells from two different organisms unite to produce the first cell of the new organism For most multicellular organisms Asexual Reproduction The new organism has a single parent A unicellular organism can split to become two Spongebob’s challenge to Sandy: Can you reproduce by budding? Can ya?

Based on a Genetic Code Offspring usually resemble parents. Asexual reproduction means exact same traits. Sexual reproduction allows for different combinations of traits. Directions for inheritance on DNA, deoxyribonucleic acid.

Growth and Development All living things grow and develop. Unicellular get bigger. Multicellular go through development (1 cell becomes 2, becomes 4, etc.) Puberty = development

Need for Materials and Energy 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. Plants, some bacteria, and algae are producers, and get energy from the sun by photosynthesis. Primary consumers eat the plants to get energy. Secondary consumers eat what eats the plants to get energy.

Response to the Environment Organisms respond to stimuli, or signals which an organism reacts to. External stimuli include light and temperature. Internal stimuli include low glucose levels making you hungry.

Maintaining Internal Balance Internal conditions like temperature and water must be fairly consistent for organisms to survive. The process by which organisms keep consistency is homeostasis. It involves internal feedback mechanisms that work in much the same way as a thermostat. Ex. Too hot = sweat to evaporate and cool you; too cold = shiver, movement to warm you

Evolution Organisms as a group evolve, or change over time. This time is usually a few generations. For example, human brains have evolved into multitasking (the 21st century student).

Branches of Biology No one biologist could study all the living things, so biologists must specialize. Some of the fields of study include: Botany = plants Zoology = animals Study of Molecules Cells Organisms Populations Communities Biosphere

Levels of Organization Biosphere- part of Earth that contains all ecosystems Ecosystem- community and nonliving surroundings Community- populations that live together in defined area Population- group of organisms of one type that live in the same area Organism-individual living thing Group of cells- tissues, organs, organ systems Cells- smallest functional unit of life Molecules- group of atoms, smallest unit of compound

Biology in Everyday Life Helps you understand your pet(s) Helps you understand your food Treats medical problems Identifies environmental problems Is used to make decisions humans vote on (or vote for elected officials who vote on the decisions)

A Conflict of Interest Scientists can lie for financial gain, fame, future work, or favoritism Some say regulation is necessary Committees must be able to read results and see if “cheating” occurs If supervised, nothing dangerous can happen Some say regulation is unnecessary Many would not “cheat” May cut funding, so may not get next “miracle drug”