CHARACTERISTICS OF LIFE 1) 1)LIVING THINGS ARE MADE FROM THE SAME BUILDING BLOCKS, ORGANIZED INTO CELLS.

CHARACTERISTICS OF LIFE

1) LIVING THINGS ARE MADE FROM THE SAME BUILDING BLOCKS, ORGANIZED INTO CELLS

LEVELS OF ORGANIZATION

atoms

molecules nonliving = abiotic

cells living = biotic

tissues

organs

organism = living thing

Human Brain Nerve Cell

ORGANISM = living thing

Species = similar organisms, interbreed

in the wild, only with each other

Species = reproductively isolated group

of organisms

Species = one kind of organism

population = all members of the same species,

that live together in same area, at same time

community = all populations (plants & animals)

that live together in same area, at same time

physical environment = non living (abiotic)

air, rocks, soil, water, light, climate

ecosystem = community + physical environment

biosphere = all organisms on Earth

= all communities on Earth

= all life on Earth

CHARACTERISTICS OF LIFE

2) ORGANISMS GROW & MAINTAIN THEIR ORGANIZATION BY GETTING MOLECULES & ENERGY FROM THE ENVIRONMENT

Autotrophs = self feeding= self feeding

Energy Flow: Sunlight Sunlight Food Molecules Food Molecules Work Work

HeatHeat

= plants, algae, some bacteria= plants, algae, some bacteria

Heterotrophs = other feeding (eaters)= animals, fungi, bacteria

Energy Flow: Food Molecules Work (stay organized)

Heat (to atmosphere)(to atmosphere)

CHARACTERISTICS OF LIFE

3) ORGANISMS MOVE OR OTHERWISE RESPOND TO CHANGES (STIMULI) IN THE EXTERNAL ENVIRONMENT

Response = Behavior

CHARACTERISTICS OF LIFE

4) ORGANISMS REPRODUCE &

PASS ON THEIR DNA TO THEIR OFFSPRING

DNA = Instructions

CHARACTERISTICS OF LIFE

5) GROUPS OF ORGANISMS SHOW VARIATIONS & EVOLVE, OR CHANGE, TO ADAPT TO THEIR ENVIRONMENT

Source of variations = mutations,which are changes in DNA

and new combinationscreated by sexual reproduction

Evolution = changes in a population over time

Natural Selection = nature selects the changes

LIFE MODEL

Survival= First Priority for Resources Is Stay Alive

Growth = Extra Resources must be available

Reproduction = Extra Resources must be available

Science

SCIENCE = derived from a Latin verb meaning “to know”

= seeks natural causes for natural phenomena

Includes two forms of inquiry;

1) Discovery (descriptive) science

2) Hypothesis-driven science

Discovery Science

Observations of nature

Human genome project

Inductive conclusion is a generalization based on many specific observations

Ex. “All organisms made of one or more cells”

Hypothesis-driven Science

Scientific Method = series of steps that form a formal process of inquiry

Deductive conclusion is using the general premise to predict a specific result

Follows “if…then” logic, i.e. if all organisms are made of cells, & humans are organisms, then humans are made of cells.

HYPOTHESIS

Can be shown to be false

Can NOT be proved true, only supported by results

Example:

I am the fastest runner in the world

Fly Mimicry Experiment

OBSERVATIONS

Jumping Spiders

1) stalk and pounce on flies

2) wave their legs to scare off other jumping spiders

Jumping Spider

Fly Mimicry Experiment

OBSERVATIONS

Spider-mimicking flies

1) have markings on their wings that look like

spider’s legs

2) wave their wings (false legs) at spiders

Fly Mimicry Experiment

QUESTION #1

Does mimicry (looking like jumping spiders) actually turn real jumping spiders away?

Fly Mimicry Experiment

HYPOTHESIS

Mimicry (looking like jumping spiders) does turn real jumping spiders away.

Fly Mimicry Experiment

Control Group (of organisms) =

Normal Spider-mimicking flies

Experimental or Treatment Group (of organisms) =

Flies with wing markings or “legs” masked

Fly Mimicry Experiment

Manipulated or Independent Variable = difference between two groups

that is being tested

= looking like jumping spiders

Fly Mimicry Experiment

Responding (Dependent) Variable = results that may be different between the two groups being compared

Responding (Dependent) Variable = Pounce rate (% of trials in which spiders jumped on the fly)

Fly Mimicry Experiment

Controlled Variables or Constants =

all factors that are the same between the two groups

Fly Mimicry Experiment

Results = spiders pounced on treatment group more than controls, as shown on graph

Conclusion = the results support the hypothesis that mimicry (looking like jumping spiders) did turn jumping spiders away

Fly Mimicry Experiment

OBSERVATIONS

Jumping Spiders

1) stalk and pounce on flies

2) wave their legs to scare off other jumping spiders

Jumping Spider

Fly Mimicry Experiment

OBSERVATIONS

Spider-mimicking flies

1) have markings on their wings that look like

spider’s legs

2) wave their wings (false legs) at spiders

Fly Mimicry 2nd Experiment

QUESTION #2

Are both types of mimicry;

(acting & looking like jumping spiders)

required to turn real jumping spiders

away?

Fly Mimicry 2nd Experiment

HYPOTHESIS

Both types of mimicry (acting & looking) like jumping spiders) are required to turn real jumping spiders away.

Fly Mimicry 2nd Experiment

Manipulated Variables = difference between two groups that are being tested

Mimicry = looking like jumping spiders

= wing markings

Mimicry = acting like jumping spiders

= wing waving

Fly Mimicry 2nd ExperimentFive Test Groups of Flies

1) Normal spider mimics

2) Mimics w/ mimic wing transplants

3) Mimics w/ housefly wing transplants

4) Houseflies w/ mimic wing transplants

5) Normal houseflies

Fly Mimicry 2nd Experiment

Dependent Variable = results that may be different between the two groups being compared

Dependent Variable = actual number of stalk and attack responses by spiders

Fly Mimicry 2nd Experiment

Results = spiders stalked and attacked groups without both types of mimicry more often than groups with both types

Conclusion = the results support the hypothesis that both types of mimicry (acting & looking like jumping spiders) are required to turn jumping spiders away

According to the National Academy of Sciences,Some scientific explanations are so well established that no new evidence is likely to alter them. The explanation becomes a scientific theory. In everyday language a theory means a hunch or speculation. Not so in science. In science, the word theory refers to a comprehensive explanation of an important feature of nature that is supported by many facts gathered over time. Theories also allow scientists to make predictions about as yet unobserved phenomena.

Scientific Theory

According to Stephen Hawking, "a theory is a good theory if it satisfies two requirements: It must accurately describe a large class of observations on the basis of a model which contains only a few arbitrary elements, and it must make definite predictions about the results of future observations".

Isaac Newton's theory of universal gravitation is a physical law describing the gravitational attraction between bodies with mass.

It states the following:

Every object attracts every other object by a force pointing along the line intersecting both objects. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between the objects.

Is it supported by many facts gathered over time?

Does it allow scientists to make predictions about as yet unobserved phenomena?