Biology Lecture Notes – Characteristics of Living Things
Studying Life Characteristics of Living Things What are some characteristics of living things? No single characteristic is enough to describe a living thing. Some nonliving things share one or more traits with living things. Living things share the following characteristics: made up of units called cells reproduce based on a universal genetic code grow and develop obtain and use materials and energy respond to their environment maintain a stable internal environment change over time Characteristics of Living Things Living things are made up of cells.
A cell is the smallest unit of an organism that can be considered alive. Characteristics of Living Things Living things reproduce. In sexual reproduction, cells from two different parents unite to form the first cell of the new organism. In asexual reproduction, a single parent produces offspring that are identical to itself. Characteristics of Living Things Living things grow and develop. During an organism’s development, cells differentiate, which means that the cells look different from one another and perform different functions. Characteristics of Living Things
Living things are based on a universal genetic code. Organisms store the information they need to live, grow, and reproduce in a genetic code in a molecule called DNA. Characteristics of Living Things Living things obtain materials and use energy. The combination of chemical reactions through which an organism builds up or breaks down materials is called metabolism. Characteristics of Living Things Living things respond to their environment. A stimulus is a signal to which an organism responds. Characteristics of Living Things Living things maintain a stable internal environment.
Although conditions outside an organism may change, conditions inside an organism tend to remain constant. This process is called homeostasis. Characteristics of Living Things Taken as a group, livings things change over time. Over many generations, groups of organisms typically evolve. Big Ideas in Biology Science as a Way of Knowing Science is not just a list of “facts. ” The job of science is to use observations, questions, and experiments to explain the natural world. Interdependence in Nature All forms of life on Earth are connected together into a biosphere, which literally means “living planet. The relationship between organisms and their environment depends on both the flow of energy and the cycling of matter. Matter and Energy Life’s most basic requirements are matter that serves as nutrients to build body structure and energy to fuel the processes of life. Cellular Basis of Life Organisms are composed of one or more cells, which are the smallest units that can be considered fully alive. Information and Heredity Life’s processes are directed by information carried in a genetic code that is common, with minor variations, to every organism on Earth.
That information, carried in DNA, is copied and passed from parents to offspring. Unity and Diversity of Life All living things are fundamentally alike at the molecular level, even though life takes an almost unbelievable variety of forms Evolution In biology, evolution, or the change in living things through time, explains inherited similarities as well as the diversity of life. Structure and Function Structures evolve in ways that make particular functions possible, allowing organisms to adapt to a wide range of environments. Homeostasis
An organism’s ability to maintain a relatively stable internal environment in the face of changing external conditions is vital to its survival. Science, Technology, and Society Science seeks to provide useful information, but only a public that truly understands science and how it works can determine how that information should be applied. Branches of Biology There a many branches of biology. For example: Zoologists study animals. Botanists study plants. Paleontologists study ancient life. The job of science is to use observations, questions, and How can life be tudied at different levels? Branches of Biology Some of the levels at which life can be studied include: molecules cells organisms populations of a single kind of organism communities of different organisms in an area the biosphere Biosphere The part of Earth that contains all ecosystems Branches of Biology Ecosystem Community and its nonliving surroundings Branches of Biology Community Populations that live together in a defined area Population Group of organisms of one type that live in the same area Organism Individual living thing Groups of Cells
Tissues, organs, and organ systems Cells Smallest functional unit of life Molecules Groups of atoms; smallest unit of most chemical compounds At all these levels, smaller living systems are found within larger systems. Biology in Everyday Life More than any other area of study, biology touches your life every day. Biology provides information about the food you need and the methods for sustaining the world’s food supplies. Biology describes the conditions of good health and the behaviors and diseases that can harm you. Biology is used to diagnose and treat medical problems.
Biology identifies environmental factors that might threaten you. Biology in Everyday Life Biology helps you understand what effects the quality of your life. Biology provides decision makers with useful information and analytical skills needed to predict and effect the future of the planet. Quiz 1-3 An increase in size is known as growth. metabolism. development. differentiation. Which of the following is NOT a characteristic of all living things? use of energy made of cells stable internal environment need for oxygen Which of the following are branches in the study of biology? ells, tissues, organs, and organisms botany, cell biology, ecology, and zoology populations, communities, and ecosystems the genetic code, evolution, and the biosphere The genetic code is carried in Water. DNA. proteins. soil. Which of the following shows the levels of organization in correct order from the simplest to the most complex? organisms, cells, populations, molecules, ecosystems ecosystems, populations, organisms, cells, molecules molecules, cells, organisms, populations, ecosystems molecules, organisms, cells, populations, ecosystems