BIOLOGY THE SCOPE OF LIFE

TWO WAYS TO STUDY BIOLOGY Discovery approach: observe and describe objects at many levels - ie. Dissection, Human genome project, description of DNA Hypothesis based approach: - propose a hypothesis, make deduction, test prediction TWO WAYS TO STUDY BIOLOGY

The Scientific Method

Steps to solving a problem using the scientific method. State the problem Form a hypothesis Test hypothesis Steps to solving a problem using the scientific method.

Testing the hypothesis Control Group – no change Experimental Group – changes Testing the hypothesis

Testing : (cont.) Involves variables – something that changes Two types of variables - Independent – the one that you change - Dependent – the one that changes because of the independent variable Testing : (cont.)

Record & analyze data Form a conclusion Replicate Steps cont’d

CONTROLLED EXPERIMENTS

Sample experiment Problem - Does the temperature of air cause leaves of maple trees to change color? Hypothesis - Colder temperatures cause change in color of maple trees. Sample experiment

Testing the hypothesis Independent variable – temperature Dependent variable – change in color Testing the hypothesis

Control group - a group of maple trees that are kept at room temperature (22° C) Experimental group - a group of maple trees that are kept at colder temperatures (14° C) CONT.

Collection of Data (Qualitative & Quantitative) Count number of green leaves each day Run experiment for a given number of days - You need at least 20 - 30 days of data for plants Record data on a chart Plot data on graph Collection of Data (Qualitative & Quantitative)

Cold temperatures do not cause maple leaves to change color Form a Conclusion

The Properties of Life

1. Made of Cells Unicellular – single celled Multicellular – many cells Prokaryotic- simpler, smaller, does not have a nucleus or most organelles. Eukaryotic –most forms of life, contains a definite membrane- bound nucleus and other organelles 1. Made of Cells

2. REPRODUCE Sexual -- 2 cells required Asexual -- single organism reproduces 2. REPRODUCE

3. GROW AND DEVELOP

4. OBTAIN & USE ENERGY Anabolism - putting substances together thus storing energy - photosynthesis - protein synthesis Catabolism - breaking down substances thus releasing energy - digestion Metabolism - sum total of all chemical reactions in organism 4. OBTAIN & USE ENERGY

5. RESPOND TO ENVIRONMENT Stimuli - anything that causes a response Responses - improve chances for survival - maintain homeostasis which is the balance within the organism 5. RESPOND TO ENVIRONMENT

Scientists continue to try to classify all life Scientists continue to try to classify all life. There are many different classification schemes. Most agree on 3 groups called domains. DIVERSITY OF LIFE

3 Domains: - Bacteria - Archae -Eukarya DIVERSITY OF LIFE

DIVERSITY OF LIFE Kingdoms – change is still in the works - Plants - Animals - Fungi - Many kingdoms of Protists DIVERSITY OF LIFE

BRANCHES AND LEVELS OF BIOLOGY

BRANCHES Zoology - animals Botany - plants Microbiology - microscopic organisms Ecology - how organisms interact with environment BRANCHES

Molecular Organelle Cellular Tissue Organ Organ systems LEVELS

Organism Population Community Ecosystem Biosphere Levels

Evolution: Biology’s Unifying Theme Evolution- genetic change in a population over time Charles Darwin- Father of Evolution -Descent with modification -Natural Selection (Reproductive Success) Evolution: Biology’s Unifying Theme

The Evolutionary Tree of Mammals This chart illustrates how the various mammal groups are related to one another. Groups that share more recent common ancestors are located on branches that are closer to each other. The Evolutionary Tree of Mammals

ECOLOGY Interactions of organisms w/each other & their physical environment

Population - Individuals of same species living in a given area Population - Individuals of same species living in a given area. A species must breed with each other. Community – All the populations in a given area. Limiting factor – factors that restrict population growth - water, oxygen, light Terms

Terms Ecosystem – a community and its physical factors (abiotic) Biosphere - Part of earth where life exists – sum of all ecosystems Terms

Producer – makes organic food CO2, H2O, and other inorganic material(Primary,Secondary,tertiary) Consumer – gets food by eating plants or organisms that ate plant Decomposer – gets energy from organic waste or dead organisms - (aka detritivore) Foodchains: Grass →antelope→human→lion Food web: all the food chains in an ecosystem Terms

Question How is a community different from an ecosystem? - Community refers to only the living org. while ecosystem refers to both abiotic and biotic factors. Question

Ecological Succession Change in ecosystem over time. Examples: - worms change soil - trees grow tall and shade forest - both of these affect other life forms Ecological Succession

Ecological Succession Ecological succession leads to “climax community” which is fairly stable Is it ever reached? Why or Why not? Example - beech-maple forest - bog Ecological Succession

Pop. Density Predators and Prey-survival relationship which gives an ecosystem diversity of niches.(role of organism) Predator-an organism that actively hunts other organisms. The organism that is being hunted is the prey. The abiotic and biotic factors that define a Niche, also limit a specie’s growth, by limiting population size. Ex: more food in summer/winter. Any population has the potential to increase exponentially, that is where the growth in each generation is a multiple of the previous generation, IF it has a perfect environment. The Growth curve would look like a “J.” Pop. Density

The number of individuals that can be supported by an ecosystem is called the CARRYING CAPACITY for that specie Carrying capacity of a specie in a particular ecosystem is usually represented by an S- shaped graph or “logistic growth curve” Growth Curves

Limiting factors Density Dependent limiting factors- Limiting factors that are dependent on population size. Ex: food supply, predation, disease, competition. Density-independent limiting factors-limiting factors that affects the same percentage of a population regardless of its size. EX: natural disasters (hurricanes, fires) limit growth by destroying habitat Limiting factors

Humans effects on ecosystems Pollution Global Warming – pg. 394-399 Deforestation Humans effects on ecosystems

 biodiversity  the variety of life on Earth, along with the habitats they depend upon -biodiversity hot spots-small areas with lg. # of endangered and threatened species Main goal of conservation biology- counter the loss of biodiversity Sustainable development-"Development that meets the needs of the present without compromising the ability of future generations to meet their own needs." Terms

The Human Population Studies of the Human ecological footprints show: Already overshot the planet’s capacity to sustain us US consumes a disproportionate amount of food and fuel Number one country contributing to fossil fuel depletion and greenhouse gases Our growth curve has been an exponential one for a long period of time. The Human Population