What Does it Mean to Be Alive? What Are The Characteristics of Life?

Is Fire Alive?

copyright cmassengale What is Biology? Biology is the study of all living things Living things are called organisms Organisms include bacteria, protists, fungi, plants, & animals copyright cmassengale

Characteristics of Life! All living things share some basic properties  Eight Characteristics of Life M  Metabolism R  Respond to Stimuli G  Growth & Development R  Reproduction U  Universal Genetic Code C  Composed of cells (+1) H  Homeostasis E  Evolve & Adapt

METABOLISM: All living organisms obtain & use energy to grow, develop, repair damage, and reproduce

Living organisms and energy… 1. PRODUCERS: - Plants and other photosynthetic organisms - Produce their own food (from CO2, H2O, & the sun) upon which the entire ecosystem depends 2. CONSUMERS: - Animals: Obtain nutrients and energy from consuming the food made by producers

Anabolism Requires Energy Process of building up complex substances from simpler substances Building up cells and cellular components Photosynthesis Requires Energy

Catabolism ReleasesEnergy Process of breaking down complex substances into simpler substances to release energy Digestion Cellular Respiration ReleasesEnergy

Metabolism All chemical reactions occurring within an organism Anabolism + Catabolism = Metabolism

All Living Things R e s p o n d to Their Environment Example: A plant’s leaves and stems grow toward light Organisms react to stimuli: Light Temperature Odor Sound Gravity Heat Water Pressure

ALL ORGANISMS GROW & DEVELOP Growth & Development ALL ORGANISMS GROW & DEVELOP What’s the difference?

All Living Things Grow Growth means to get bigger in size

All Living Things Develop Development involves a change in the physical form or physiological make-up of an organism

All Living Things Reproduce Reproduction is the process of producing new organisms of the same type Asexual Reproduction A single parent organism reproducing by itself

Sexual Reproduction Two different parent organisms contribute genetic information Involves the combination of male and female sex cells

Universal Genetic Code Genes carry hereditary information Genes are composed of DNA Heredity is the reason children resemble their parents Mutations change the DNA code and can be passed from generation to generation

Cellular Organization Living organisms Consist of organic molecules  organized to form cells Cells = Life’s basic units of structure and function Are composed of one or more cells

All Living Things are Made Up of Cells Smallest unit capable of all life functions Unicellular Organisms Entire organism is made up of one single cell Bacteria and protists

Multicellular Organisms The organism is made up of many cells Cells have specialized functions within the organism

copyright cmassengale Facts About Cells Cells are the smallest living unit of an organism All cells contain living material called cytoplasm All cells are surrounded by a cell membrane that controls what enters & leaves the cell copyright cmassengale

copyright cmassengale More Cell Facts Cells are complex & highly organized Cells have parts called organelles that do different jobs e.g. Chloroplasts in plants make sugars copyright cmassengale

copyright cmassengale More Cell Facts The simplest cells are called Prokaryotes These cells DO NOT have a nucleus or membrane-bound organelles Bacteria are examples copyright cmassengale

copyright cmassengale More Cell Facts More complex cells are called Eukaryotes These cells DO have a nucleus and membrane-bound organelles Plants, animals, protists, & fungi are examples copyright cmassengale

all organisms maintain Homeostasis A stable state of conditions in the body that are necessary for life Body temperature Blood volume pH balance Water balance

Living Organisms are Homeostatic Homeostasis: Ability of an organism to maintain relatively constant internal conditions * Example: Temperature regulation in the human body All organ systems contribute to homeostasis

All living things adapt to their environment through evolution …and Adaptation All living things adapt to their environment through evolution

All Living Things Adapt to Their Environment Through Evolution Adaptation A process that enables organisms to become better suited to their environment Species obtain adaptations through evolution, which occurs over great periods of time

An Example of Adaptation Desert plants have succulent waxy leaves and stems to store water and reduce water loss

Characteristics of Life! All living things share some basic properties  Eight Characteristics of Life M  Metabolism R  Respond to Stimuli G  Growth & Development R  Reproduction U  Universal Genetic Code C  Composed of cells (+1) H  Homeostasis E  Evolve & Adapt

Life is Organized on Several Levels copyright cmassengale

copyright cmassengale Levels Atoms Molecules Organelles Cells – life starts here Tissues Organs Organ Systems Organism copyright cmassengale

copyright cmassengale Levels Population Community Ecosystem Biosphere copyright cmassengale