BIOL 13 Sec 1 & 2 - Exam #1 Review

%%The Process of Science%%

The Scientific Method: a way of studying the natural world through observations, hypotheses, and deductive reasoning

The Steps in the Scientific Method:

Make Observations Ask Questions Make Hypotheses Generate Testable Predictions from Hypotheses Devise Tests (Experiments) Type of study: prospective or retrospective

Retrospective study: A study that involves data or subjects or events or effects that have happened in the past. eg. surveys, observational studies, correlation studies

Prospective study: A study that examines events/effects that will happen in the future. eg. Clinical trials

Elements of a good experiment:

Use a control group (a group that does not receive the treatment or drug) as a baseline for comparison.

treatment group: an experimental manipulation (e.g. patients who receive a drug for their illness)

control group: identical to the treatment but without the manipulation (e.g. patients who receive a placebo -- a pill with nothing in it for their illness)

Account for other variables that might affect the outcome of the experiment.

controlled or standardized variable: parameters that the researcher is able to control (keep constant) during the experiment (e.g. start of illness -- include only patients that are just starting to become ill, or diet -- include only patients on a healthy diet, or age – include only patients between 20-30 years old)

uncontrolled variable: parameters that the researcher is unable to control or keep constant during the experiment (e.g. diet, exercise, stress level in patients, etc.)

Use an appropriate number of subjects in your sample.

sample size: is the number of people or subjects included in your study (counting subjects in both the treatment group and the control group)

Randomize the subjects: place the subjects randomly into the treatment and control groups

Get a representative sample

representative sample: is a group of subjects that includes the diversity of people you wish to study

Be as objective as possible. The researcher must avoid any attempts to affect the outcome of the study. A double blind study is the most objective study.

blind study: a study where the participants do not know whether they have received a drug or a placebo

double blind study: a study where both the participants AND the researcher do not know who in the study has received a drug or a placebo

objectivity: uninfluenced by emotion or personal prejudice; based on observable phenomena

Definitions

dependent variable: the variable that is measured by the experimenter; it depends on the outcome of the experiment

independent variable: the variable that the experimenter intentionally manipulates; what is being studied

anecdote: a single, life experience that one uses to provide information about a cause and effect / an event / or the natural world

%%Natural History of CA%%

California: A Natural History of California (or Why California is the most interesting state!)

California has 24 different major habitat types; most states have on average 4 different habitat types -- due to a unique climate, geology, and topography

California has a great many microclimates: climate on a very local scale, which differs from the general climate of the surrounding area

Compared to any other U.S. state (except Hawaii), California has:

-- the highest number of species (biodiversity)

-- the highest number of endemic species (species that are restricted to living in a particular area)

-- the highest number of endangered/threatened species

biodiversity: the total number of different species present in an area

endemic species: a species that is restricted to living in a certain habitat, or a certain set of environmental conditions

%%Basic Ecology%%

Ecology : the scientific study of the interactions among organisms as well as the interactions between organisms and their non-living environment

Abiotic factors : non-living, environmental factors; e.g. water, temperature, light, nutrients

Biotic factors : living organisms and their interactions; e.g. competition, predation

Trophic levels:

producers = autotrophs; organisms that make their own food (plants)

consumers = heterotrophs; organisms that consume food; herbivores, omnivores, carnivores

decomposers = organisms that feed on dead or decaying plants / animals

The Physical Environment:

Geology -- rocks and soil Topography -- shape of the earth Climate -- weather

is affected by 2 factors: temperature and precipitation; there 2 factors are influenced by latitude, elevation, the ocean, and topography

Local effects:

rain shadow: an area of little rainfall due to the presence of a high mountain (eg. Eastern side of Sierra Nevada mountains)

temperature inversion layer: area of inverted temperature due to presence of valley with no outlet for dense fog

Organisms both Respond and Adapt to Environmental Conditions

primary productivity = rate at which producers convert solar energy into chemical energy (convert to their body tissue; or biomass)

nutrient and energy flow:

nutrient flow = cyclic

energy flow = unidirectional

%%Resources%%

Renewable:

solar energy, winds, tides

clean air, water, soil, animals / plants

Non-renewable:

fossil fuels (coal, oil, natural gas)

minerals, clay, salt, etc.

Ecological Footprint

Our ecological footprint is a measure of how much of the earth is needed to produce the energy and breakdown the pollution from 1 person

Environmental Impact Formula:

EI (Environmental Impact) = P (# people) x A (affluence or ave. resource use) x T (technological impact)

(T = the harmful and beneficial impacts of the technologies involved in consumption)

(Affluenza = a term used to describe the unsustainable addiction to over-consumption and materialism exhibited in the lifestyles of affluent consumers in the U. S.)

Sustainability: ability to use resources indefinitely such that they naturally replenish themselves; using resources with minimal inputs and minimal outputs; principle of sustainability = there is a fixed supply of nutrients which are continually recycled

natural capital = natural resources that keep humans (and all species) alive and support human economies

ecosystem services = natural services that support humans (and all species) and support human economies

Nutrient Cycles

Water cycle

includes evaporation (from surface water), transpiration (water leaving plants), and precipitation (water falling to ground)

Carbon cycle

includes the process of photosynthesis and respiration; plants take in CO2 and animals let out CO2

Nitrogen cycle

includes the process of nitrogen fixation and nitrogen release; nitrogen fixing bacteria remove N2 from the atmosphere and convert it to forms of nitrogen usable by plants

Humans disrupt all 3 processes by a variety of human activities

%%Population Growth%% \n

Population: is a group of individuals of the same species living in the same environment; close enough so that they can interact

Limits to population growth are both abiotic and biotic \n

How do populations grow?

exponential growth, logistic growth

r = intrinsic rate of growth of a population; a feature of the species

K = carrying capacity of the habitat; a feature of the environment

Demography: factors that describe the size and structure of populations

Age structure: the number of individuals in a population of a specific age

Sex ratio

Survivorship curves (type I, II, and III); # of individuals surviving to each age group; shows distribution of mortality with age

Fertility: # of offspring per female lifespan

Density

Dispersion (clumped, random, uniform)

Human population growth is affected by abiotic and biotic factors, but also culture, religion, etc.

What are the dangers of overpopulation?

What are some solutions to the problems posed by overpopulation?

r-selected individuals: species that are evolved to maximize their "r"

K-selected individuals: species that are evolved to maximize there ability to live in their environment

%%Agriculture%%

The problems of modern agriculture:

loss of genetic diversity due to: due to grafting, cloning, genetic engineering, etc.
overuse of "inputs" (pesticides, fertilizers, water, etc.)
erosion of soil (not enough use of "alternative practices" like inter-cropping and crop rotation
not enough use of locally-grown food, not enough small farms
over-commercialization of food
over-processing of food
not an equitable distribution of land/food/resources

Did the Green Revolution (which increased crop yields) solve world hunger?

The problems and the potential of genetic engineering

Will the Second Green Revolution (GMO's) solve world hunger?

Alternative Methods:

Alternative Methods

intercrop: a sustainable farming technique where 2 or 3 crops are grown together in the same field (usually alternating rows of 2 different crops)
crop rotation: rotating 2 or more crops on a particular field (so the same crop is not grown repeatedly) – this helps to prevent soil depletion
legumes: plants in the pea family (peas, beans) – these plants have nitrogen-fixing bacteria in their roots and help replenish nitrogen in the soil
border crop: a row of non-food plants (flowers or native bushes) that line the edge of fields meant to attract beneficial organisms (insects, bats, birds – that will eat pest insects on the farm)
cover crop: planting a non-food crop in a field to help replenish the soil nutrients –usually involves a non-food legume or other plant with nitrogen-fixing bacteria
permaculture: a system of land management that works with the natural processes of ecosystems