The Scope of Biology

Ten Themes Unify The Study of Life.

objective

Identify major organizational levels of life. From global scale to microscopic scale

Biosphere

Global scaleBiosphere consists of three parts that are

inhabited by living things: Most regions of land Most bodies of water (oceans, lakes, rivers) Atmosphere (altitude of several kilometers)

Ecosystems

Ecosystem-the community of living things in an area, along with nonliving features of the environment that support the living community.Ex. Woodland are (park)

Living: trees, plants, animals, bacteria

Nonliving: sunlight, water, air, soil All of Earth’s ecosystems combined make up

the biosphere

Organisms

Organisms- individual living things

Microorganisms- microscopic organisms

Interactions among the organisms of a community make each ecosystem a dynamic place.

Cells

Cells- life’s basic units of structure and function. All organisms are made up of one or more cells.

Ex, a cell of a leaf interior is ~25 μm across It would take more than 700 of these cells to reach

across a penny Cells contain even smaller structures

DNA and Genes

DNA and Genes are found inside the nucleus of a cell

Atoms- the basic building blocks of all materials (living and nonliving)

Molecule- formed when atoms bond together

DNA and Genes

DNA- a molecule (deoxyribonucleic acid) responsible for inheritance

Inheritance-the passing on of traits from parent organisms to their offspring

A DNA molecule contains the instructions for a cell to make all the other molecules it needs to function.

Genes-units of inherited information along the length of each DNA molecule

Metric scale bar

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Diversity of organisms

Species-distinct form of life1.5 million species have been identified,

new species are discovered almost daily!

Number of identified species

5,000bacteria

8,600 birds

30,000fish

100,000 fungi

280,000 plants

1,000,000 insects

There are also thousands of species of:

Amphibians

Reptiles

Mammals

Classifying Life

The taxonomic scheme classifies species into groups subordinate to more comprehensive groups.

Species that are very similar are placed in the same genus, genera are grouped into families, and so on, each level of classification being more comprehensive than those it includes.

ClassificationEx. The leopard, species Panthera pardus

Kingdom

Phylum

Class

Order

Family

Genus

Species

Animalia

Chordata

Mammalia

Canivora

Felidae

Panthera

Panthera pardus

Domains of Life

Domain- the broadest category in classifying life forms

Three Domains: Archaea Bacteria Eukarya

Archaea and Bacteria organisms are mostly unicellular (bodies consist of a single cell).

These cells lack nuclei (DNA is not separated from the rest of the cell)

Prokaryotic cell- cells without nuclei, simple cells

Domains are divided into kingdoms.Domain Eukarya has four kingdoms:

Protists Fungi Plants Animals

Eukaryotic cells- contain nuclei that separate DNA from the rest of the cell

Some protists, most fungi and all plants and animals are multicellular

All organisms of these four

kingdoms consist of eukaryotic

cells!

Ten themes unify the study of life!!!Themes apply to all species and to all levels of organization

1. Biological systems2. Cellular basis of life3. Form and function4. Reproduction and inheritance5. Interaction with environment6. Energy and life7. Regulation8. Adaptation and evolution9. Biology and society10. Scientific inquiry

Biological Systems

System-comprised of a combination of parts to form a more complex organization based on the arrangements and interactions of its parts.

The Cellular Basis of Life

All organisms are made of cellsCells can be specialized for different

functions and are organized into higher levels of organization.

Nerve cellNerve tissue

Organ Nervous system

Form and Function

Structure and function go hand in hand!!!Consider:

Surface Area Movement Physical attributes

Reproduction and Inheritance

Inherited information in the form of DNA enables organisms to reproduce their own kind.

Interaction with the Environment

As part of an ecosystem, each organism interacts continuously with its environment.

“inputs” and “outputs”Two major processes:

Cycling of nutrients Flow of energy from sunlight to photosynthetic

life to organisms that feed on plants

Energy and Life

Producers- produce the food upon which the entire ecosystem depends (plants and other photosynthetic organisms)

Consumers- animals and other organisms that eat the food made by the producers

Regulation

Homeostasis or “steady state”Mechanisms of homeostasis enable

organisms to regulate their internal environment, despite changes in their external environment.

Adaptation and Evolution

Adaptation- an inherited trait that helps the organism’s ability to survive and reproduce in its particular environment

Population- a localized group of organisms belonging to the same species

Natural selection- natural environment “selects” certain inherited traits

Evolution

Natural selection is the mechanism by which evolution occurs.

Evolution- “a process of change” A generation to generation change in the

proportion of different inherited genes in a population

Biology and Society

Impacts that the application of biology have on society: Stem cell research Animal cloning Environmental issues Genetically modified crops treating disease Antibiotic resistance

Scientific Inquiry

Scientific inquiry involves asking questions about nature and then using observations or experiments to find possible answers to those questions.