Bio Exam 1

Science

a body of knowledge (data) about the natural world.

- Can be detected, observed, and measured

- An evidence-based process for acquiring that

knowledge

Science is based on evidence, which:

- Can be demonstrated through observations

and/or experiments

- Must be repeatable

- Is subject to independent validation

- Is subject to peer review

The _________ is the process of

science.

scientific method

What are the limits of science?

- Can be applied only to the observable and

measurable natural world

- Cannot tell us what to do with the

information it uncovers

- Provides no help as to what is morally or

ethically right or wrong

What can’t science do?

• Speak to the existence of God or any supernatural

event or creature

• Distinguish or quantify “beauty” or lack thereof

• Answer all questions

observation

An observation is a

description,

measurement, or

record of any object

or phenomenon.

A scientific hypothesis is

- An informed, logical, and plausible explanation for

observations of the natural world

- A statement, not a question

scientific method

observe → hypothesis → prediction → test → analyze →

→ communication

→ accept, reject, or modify → hypothesis, prediction

An experiment

a repeatable manipulation of

one or more aspects of the natural world.

independent variable

is that which the

scientist manipulates.

dependent variable

is any variable that

responds, or could potentially respond, to

changes in the independent variable.

When a hypothesis is stated in the “If . . .

then” format:

- What follows the “If” is the independent

variable.

- What follows the “then” is the dependent

variable.

Experiments are divided into two groups:

Control group, Treatment group

Control group

- Is maintained under a standard set of conditions

- No change in the independent variable

Treatment group

- Is the experimental group

- Is maintained under the same standard set of

conditions as the control group

- The independent variable is, however,

manipulated.

Types of Scientific Studies

Descriptive

Analytical

Statistical

Correlation

Experimental causation

Descriptive

reporting data found in nature

analytical

looking for patterns in the data

Statistical

using math tools to quantify the

reliability of the data and their patterns

Correlation

one or more parameters behaves

in an interrelated manner

Experimental causation

one parameter can

be shown to cause the effect of the other

scientific fact

a repeatable observation of the natural world.

- May change as observations become more

accurate

scientific theory

a hypothesis, or a group

of related hypotheses, that has been

repeatedly confirmed by diverse independent

researchers.

A peer-reviewed publication prevents:

- Mistakes in experimental design

- Misinterpretation of data

- Fraud

Preventing Fraud

Scientific journals publish research only after it

has been judged by experts in the same field

as the research.

Scientific claim

a statement about how the world

works that can be tested using the scientific method

Scientific literacy

is an understanding of the basics of science and the scientific process.

- Enables us to make informed decisions about the

world around us

- Enables us to communicate our knowledge to others

Bias

a prejudice or opinion for or against

something

basic research

- Intended to expand the fundamental knowledge

of science

- Largely funded by the federal government

Applied research

- Businesses and industries provide the majority of

funding to find practical uses for scientific discoveries.

- Money is a strong motivator to support or reject a claim.

Secondary literature

Sources that give a basic overview of a topic, or summarize research results

For example: textbooks, review articles, popular science journals, respected institutions on the Internet

Primary literature

first publication of scientific research that contains actual data with controls

For example: technical reports, conference proceedings, dissertations, peer-reviewed science journals

Correlation

two or more aspects of the natural world behave in an interrelated manner

Pseudoscience

is characterized by scientific-sounding statements, beliefs, or practices that are not based on the scientific method.

Meta-analysis

analysis of the combined

results of several studies

Cohort studies

observational studies of a

group of people over a period of time

Case-controlled studies

studies comparing

patients with a disease to those without

Peer-reviewed studies

research evaluated by

peer researchers before publication

Herd immunity

occurs when a critical portion of a

population is vaccinated; then, the spread of disease

is contained.

biosphere

consists of all of Earth’s

organisms, plus the physical space we all

inhabit.

Ecology

the scientific study of interactions

between organisms and their environment

Biotic factors

other living organisms

Abiotic factors

nonliving

Climate

the prevailing weather of a region

over relatively long periods of time

• Organisms are more strongly influenced by

climate than by any other feature of their

environment.

Climate change

a large-scale and long-term alteration in Earth’s climate

Weather

short-term atmospheric conditions

in a limited geographic area

• Today’s temperature, precipitation, wind,

  humidity, and cloud cover

Global warming

a significant increase in the

average surface temperature of Earth over

decades or more

• Temperature on Earth is determined by the angle

  at which sunlight strikes the planet

What causes Global warming?

- Not dependent on how sunlight strikes the Earth

- Caused by an increase in greenhouse gases that

absorb heat that radiates from Earth’s surface and

prevents it from escaping to space

Greenhouse gases

- Carbon dioxide (CO2), water vapor (H2O), methane

(CH4), and nitrous oxide (N2O)

- Function much as the walls of a greenhouse or the

windows of a car do: they let in sunlight and trap heat

- Cause the greenhouse effect

Hydrologic cycle

the

circulation of water from

the land to the sky and

back again

Earth has four giant convection cells:

Cell 2 south: cold, dry air sinks

• Warm, moist air rises, raid falls

Cell 1 south: warm moist air cools as it rises, causing rainfall

Cell 1 north: some of the cool, dfy air sinks and is then deflected both north and south.

• The clash of moist, warm air and polar cold fronts produces rain

Cell 2 north: cool, dry air sinks

global carbon cycle

the transfer of carbon

within biotic communities and their physical

abiotic surroundings

Carbon is transferred between the biotic and

abiotic through:

- Photosynthesis:

• Sunlight, water, and CO2 become sugar and O2.

- Respiration:

• Take up O2 and release CO2 through metabolism

- Combustion:

• The burning of carbon-rich materials, living or not

Carbon sink

a natural or artificial reservoir that

absorbs more carbon than it releases

Carbon source

a natural or artificial reservoir

that releases more carbon than it absorbs

Ecological footprint

the area of the biosphere

required to produce the resources and to

absorb the waste produced by an individual or

population

Earth equivalents

the number of planet

Earths needed to provide the resources and

absorb the waste of an individual or

population

An action or process is sustainable if

it can be continued indefinitely without causing serious

damage to the environment.

Ecological Footprint Depends on

Four Main Types of Resource Use

1. Carbon footprint

• Energy use

2. Food footprint

• The land and energy and water it takes to grow what you eat and drink

3. Built-up land footprint

• Includes the building infrastructure (from schools to malls) that supports your lifestyle

4. Goods-and-services footprint

• Includes your use of everything from home appliances to paper products

Population

a group of organisms of the same

species in a defined area

Population size

the total number of individuals

in the population

Population size usually changes over time

- An increase or decrease depends on the number of:

• Births and deaths in the population

• Individuals that enter (immigrate) or leave (emigrate) the

population

- Birth and immigration increase population size.

- Death and emigration decrease population size.

Carrying capacity

the number of individuals that can live in an

environment indefinitely

Population ecology

the study of the size and structure

of populations and how they change over time and space

Population density

the number of individuals per unit of

area

- Calculated by dividing the total population size by the area

of interest

Population doubling time

the time it takes a population

to double in size

- A good measure of how fast a population is growing

Exponential growth

growth of a population with no

constraints on its resources

- Occurs when a population increases by a constant proportion

over a constant time interval (such as one year)

- Is represented by a J-shaped growth curve

Logistic growth

growth of a population that approaches

its carrying capacity because of constrained resources

- Occurs with nearly exponential growth at first, but then

stabilizes at the maximum population size that can be

supported indefinitely by the environment

- Is represented by an S-shaped growth curve

Density-dependent population change

- Occurs when birth and death rates are affected by

population density

- When many individuals occupy the same space and,

therefore, compete for resources

Density-independent population change

- Occurs when population size is affected by factors that

have nothing to do with the density of the population

Irregular fluctuations in population size

populations of many species rise and fall

unpredictably over time.

Cyclical fluctuations

predictable population rise and fall

patterns

Ecological communities

associations of species

that live in the same area and interact with one

another

Relative species abundance

how common one

species is relative to another

Species richness

total number of species living in a

community

High relative species abundance

- One species dominates

the community.

- The community is less

diverse

High species richness

- Many species are present

in the community.

- The community is more

diverse.

keystone species

a species that has a disproportionately large

effect on a community, relative to the species’ abundance, holding the community together.

Food chain

simple list of who eats whom

Food web

a more complex diagram of several

food chains in a single ecosystem

Producers

organisms at the bottom of a food

chain that convert sunlight energy into food

energy

Consumers

organisms that get energy by eating

others below them on a food chain

Consumers

organisms that obtain energy by eating all or parts

of other organisms or their remains

Hierarchy of Consumers

• Primary consumers

• Secondary consumers

• Tertiary consumer

• Quaternary consumer

There are four central types of species

interactions in communities

1. Mutualism

2. Commensalism

3. Predation

4. Competition

Mutualism

Two species interact: both benefit.

Commensalism

Two species interact: one benefits, the other is unharmed.

Predation

Two species interact: one benefits, the other is harmed or

destroyed.

Competition

Two species fight for a common resource.

Primary consumers

Elk eat aspens (producers).

Secondary consumers

Wolves eat elk (primary consumers) that ate aspens (producers).

Tertiary consumer

A bird that eats a spider (secondary consumer) that ate a beetle (primary consumer) that ate a plant (producer)

Quaternary consumer

A killer whale that eats a leopard seal (tertiary consumer) that ate a sea bass (secondary consumer) that ate a krill (primary consumer) that ate a phytoplankton (producer)

Predator

consumer that eats part or all of other organisms

Parasite

a kind of predator that lives in or on the organism it

harms, its host

Pathogens

parasites that cause disease in their hosts

Herbivores

animals that eat plants

Carnivores

animals (and, in rare cases, plants) that kill other

animals for food

Omnivores

eat both animals and plants

Scavengers

eat dead or dying plants and animals