Characteristics of Life What does it mean to be alive?

What common characteristics of all of these tell you that they are alive? Egg Plant You Frog

Characteristics of Life Reproduction – necessary for species to survive. Growth and development Change in shape and size

Characteristics of Life Energy to carry out life’s processes Cells smallest unit of life – all living things have cells

Characteristics of Life Response to stimulus - respond to environment (positively or negatively) Adaptation through evolution – changes that allow the organism to survive and can be passed on to subsequent generations

Characteristics of Life Maintain Homeostasis Internal Stable state Ex: Body temp, Blood content, pH balance, water balance, heart rate, etc

Characteristics of Life Organization – degree of order within and around the individual that allows life to exist. Levels of complexity Smallest level of complexity – ATOM Highest level - BIOSPHERE

Fig. 1-1a, p.5 Atom Smallest unit of an element that still retains the element’s properties. Electrons, protons, and neutrons are its building blocks. This hydrogen atom’s electron zips around a proton in a spherical volume of space.

Fig. 1-1b, p.4 Molecule Two or more joined atoms of the same or different elements. “Molecules of life” are complex carbohydrates, lipids, proteins, DNA, and RNA.

Fig. 1-1c, p.4 Cell Smallest unit of life that can live and reproduce on its own or as part of a multi-celled organism. It has an outer membrane, DNA, and other components.

Fig. 1-1d, p.4 Tissue Group of cells that carry out a specific Many cells ( white ) made this bone tissue from their own secretions.

Fig. 1-1e, p.5 Organ Structural unit made of two or more tissues interacting in some task. A parrotfish eye is a sensory organ used in vision.

Fig. 1-1f, p.5 Organ system Organs interacting physically, chemically, or both in some task. Parrotfish skin is an integumentary system with tissue layers, organs such as glands, and other parts.

Fig. 1-1g, p.5 Organism Individual made of many different of system. Cells of most multicellular organisms, including this Red Sea parrotfish, are organized as tissues, organs, and organ systems.

Fig. 1-1h, p.5 Population Group of single-celled or multicellular individuals of the same species occupying a specified area. This is a fish population in the Red Sea.

Fig. 1-1i, p.5 Community All populations of all species occupying a specified area. This is part of a coral reef in the Gulf of Aqaba at the northern end of the Red Sea.

Fig. 1-1j, p.5 Ecosystem A community that is interacting with its physical environment. It has inputs and outputs of energy and materials. Reef ecosystems flourish in warm, clear seawater throughout the Middle East.

Fig. 1-1k, p.5 The Biosphere All regions of the Earth’s waters, crust, and atmosphere that hold organisms. In the vast universe, Earth is a rare planet. Without its abundance of free-flowing water, there would be no life.