Organisms & Life

What is life? Biology is the study of life of living things. This class is focused on Botany ..the study of plants but much of the material we will cover is germane to all living things. What are the criteria for life? What do you have to have to be considered alive? 1. All living things are composed of cells 2. Self regulating metabolism 3. Movement 4. Respond to stimuli 5. Reproduce 6. Adapt to the environment Anything else? Any of these we could do wihtout?

All living things are composed of cells Cell is the smallest unit of living matter some living things are composed of a single cell others of collections of specialized cells Multi-celled things can grow by duplicating cells - How does growth occur? The cell is the smallest unit of living matter. The smallest living things are one celled animals, include certain bacteria and algae. Larger organisms are collections of cells, cells are differentiated by function but they act in concert with one another. Organized and cooperate. When things grow what happens? Growth can occur in one of two ways - 1. Cells themselves get larger or 2. The number of cells increase. Biological growth usually occurs from the inside out. Some organisms grow until they die (trees). Other grow unti they reach a certain point and then they stop (adulthood). As they grow these multicellular critters change, they develop, fro fertilized egg, to embryo, to fetus to infant to child to adolescent to adult

Living things have self regulating metabolisms Various functions of a living things must work together, in cooperation for the thing to live - homeostasis (automatic tendency to maintain appropriate internal environment) The mechanisms that accomplish this are called…homeostatic mechanisms Organisms have processes by which they convert food to energy, grow replacement cells, get rid of waste, and reproduce. There are numerous functions necessary to maintain the internal integrity of the living thing. These processes are responsible for growth, maintenance, reproduction and are called your metabolism. Function must work together. One system must know when to turn on and off, how much of a substance to produce when to start and when to stop. The ability or tendency of a body to maintain these systems in balance over time is called homeostasis, the mechanisms that enable it to occur are called homeostatic mechanisms In what ways do organisms respond to their environment? What happens when you get cold? Hungry? Too warm? Angry?

Living Things Move If nothing else internal movement but… Motion is inherent in life. The internal function of the internal cell requires movement and transport of material and energy. Some things can locomote others cannot Do Plnats Move? If nothing else internal movement but… Do plants move?

Respond to Stimuli All living things respond to stimuli… Changes in environment, fear, hunger, temperature, attraction, revulsion...

All things reproduce All things die species are perpetuated through reproduction reproduction Reproduction is the vehicle through which life survives and species develop. Biological success… Reproduction involves the transfer of hereditary material fromone generation to the next. The blueprint for an individual is found in DIOXYRIBONUCLAEIC ACID (DNA). In asexual reproduction the blueprint is a copy of the single parent that splits to form 2 new individuals, in sexual reproduction it is a combination of the two contributing parents own DNA.

All living things adapt to their environment or... All things adapt.

Natural Selection Charles Darwin and the HMS Beagle The Origin of Species …surmised that present forms of life have descended from previous forms of life…changes in form were a result of small changes being selected for by nature Changes were selected because they allowed the species to be more successful... Living things evolve or change over time as they adapt to their environment and changes in the environment. Some changes are more successful than other and are selected for because they give the individual a competitive advantage

IN ANY POPULATION, MEMBERS OF THE POPULATION DISPLAY SOME VARIATION FROM ONE ANOTHER

MORE ORGANISMS ARE BORN THAN SURVIVE TO REPRODUCE

RESOURCES ARE LIMITED, THEREFORE MEMBERS OF A POPULATION MUST COMPETE FOR SURVIVAL

SURVIVORS LIVE TO REPRODUCE AND PASS THEIR GENETIC CODE ON TO THE NEXT GENERATION

Life can be studied or viewed at different levels... In science we look at things in levels, we can study living things at a chemical level, exploring the biochemistry of life, or we can look at life from a systemic point of view, how do all those metabolic processes work the anatomical function of life or we can study the behavior of individuals and how they interact in a population (like members of the same species at same time, same space) or we can study how to organize all living things relative to all other living things or how communities of living things interact with each other or how the living or biotic elements of an area interact with the abiotic or globally how the biosphere function. Any thoughts on why we look at things or organize thing at levels?

Next time... Read Chapter 2 Read Learning Objectives and Key Concepts Science is a way of thinking pp 24 - 26 Inductive/Deductive Logic p 27 Scientific Method pp 27 - 32 Be prepared to discuss why the scientific method is important What the limitations are, if any, to the scientific method. What is its greatest strength? And weakness? What is the greatest impact of the scientific method?