Fundamentals of Biology Valencia College BSC1010Cnickguthrie.com/omeka/archive/files/1fee345b4dcc40246c62ca701c1d04...All cells in a multicellular organism have the same genome. Figure

1 Fundamentals of Biology

Valencia College BSC1010C

1 Studying Life

• Chapter objectives:

What Is Biology? Is All Life on Earth Related? How Do Biologists Investigate Life? How Does Biology Influence Public

Policy?

1.1 What is Biology?

Biology: Bios (Greek) meaning life …ology means a branch of learning or

the study of…

the scientific study of living things… i.e., structure, functioning, growth, origin, evolution, ecology & distribution of living organisms

Living things: all the organisms descended from a single-celled ancestor.


Characteristics of living organisms: Consist of one or more cells

Contain genetic information

Use genetic information to reproduce themselves

Are genetically related and have evolved Can convert molecules from their environment

into new biological molecules Extract energy from the environment and use it to

do biological work

Regulate their internal environment


Evolution: a central theme of biology.

Living systems evolve through differential survival and reproduction.

The processes of evolution have generated the enormous diversity of life on Earth.

6

Levels of Organization Cellular Organization

Cells

Organelles

Molecules

Atoms

The Cell is the

basic unit of life.


Unicellular organisms: a single cell carries out all the functions of life.

Multicellular organisms: made of many cells that are specialized for different functions.

Viruses are acellular

Figure 1.1 The Many Faces of Life (Part 1)

Sulfolobus E. Coli Coccolithophore

Algae

- Protist - Bacteria Archea Domain

- Prokaryotes -

Figure 1.1 The Many Faces of Life (Part 2)

(Fungi)


The study of cells was made possible by the invention of microscopes.

Robert Hooke in the 1600s described repeating units of plant material as cells.

Antony van Leeuwenhoek discovered single-celled organisms in pond water

Figure 1.2 Cells Are the Building Blocks of Life

Cork Leaf Duckweed stem


Cell Theory:

• Cells are the basic structural and physiological units of all living organisms.

• Cells are both distinct entities and building blocks of more complex organisms.

(Schleiden and Schwann 1838)


Cell Theory:

• All cells come from preexisting cells.

• All cells are similar in chemical composition.

• Most of the chemical reactions of life occur within cells.

• Complete sets of genetic information are replicated and passed on during cell division.


All of life shares a common evolutionary history

Evolution: change in the genetic makeup of biological populations through time. Charles Darwin proposed that all living

organisms are descended from a common ancestor by the mechanism of natural selection. Differential survival & reproduction

Survival of the fittest


Species: a group of organisms that can produce viable and fertile offspring with one another.

Members of one species do not normally interbreed with members of other species in nature.

Darwin proposed that living organisms are descended from common ancestors and therefore related to one another


Humans can select for desired traits when breeding animals.

Traits that increase the probability that the organism will survive and reproduce will become more common in the population.

Natural selection and other evolutionary processes (e.g., sexual selection/mating choice and genetic drift) lead to adaptation – that enhance an organism’s chances of survival & reproduction in its environment.

What is the source of information that is passed on parent to offspring?

1.1 What is Biology? Biological information is contained in a

genetic language common to all organisms

Genome: sum total of all the DNA in a cell. Contains the “blue print” for existence

DNA: the information that is passed from parent to daughter cells. consists of repeating subunits called nucleotides.

Gene: a specific segment of DNA that contains information for making a protein. Mutations are alterations in the nucleotide sequence.

All cells in a multicellular organism have the same genome.

Figure 1.4 DNA Is Life’s Blueprint

Four nucleotides are the building blocks of DNA (C, G, A, T)

DNA is made up of two strands of linked sequences of nucleotides

A gene is a specific sequence of nucleotides

The nucleotide sequence in a gene contains the information to build a specific protein


Organisms require nutrients from their environment.

Nutrients are a source of energy and materials for biochemical reactions in cells.

• Some reactions break nutrient molecules down into smaller units, releasing energy for work.

Examples of cellular work requiring energy: • Movement of molecules, or the whole organism • Synthesis - building new complex molecules from smaller

chemical units • Electrical work of information processing in nervous

systems

Figure 1.5 Energy Can Be Used Immediately or Stored


Metabolism, or metabolic rate: the sum total of all chemical transformations and other work done in all the cells of an organism.

The reactions are integrally linked – the products of one are the raw materials of the next. Any break or intruption within these sequential reactions can result in disease


Multicellular organisms have an internal environment that is not cellular.

Their cells are specialized or differentiated, and organized into tissues; tissues are organized into organs.

Organ systems are groups of organs with interrelated functions.

Figure 1.6 Biology Is Studied at Many Levels of Organization (Part 1)


Living organisms also interact:

Populations are groups of individuals of the same species that interact with one another.

A community consists of populations of all the species that live in the same area and interact.

Communities plus their abiotic environment constitute an ecosystem.

Figure 1.6 Biology Is Studied at Many Levels of Organization (Part 2)


Individuals may compete with each other for resources;

Or they may cooperate, e.g., in a termite colony.

Plants also compete for light and water, and many form complex partnerships with fungi, bacteria, and animals.


The interactions of plant and animal species are major evolutionary forces that produce specialized adaptations.

Species interactions with one another and with their environment is the subject of ecology.


Model systems: using one type of organism to understand others.

This is possible because all life is related by descent from a common ancestor, shares a genetic code, and consists of similar building blocks—cells.

1.2 How Is All Life on Earth Related?

All species on Earth share a common ancestry; they are genetically related.

– The fossil record allows study of evolutionary

relationships based on anatomy.

– Modern molecular methods allow biologists to

compare genomes to establish degrees of

relationship.

The greater the distance between genomes, the

more distant the common ancestor.

Figure 1.7 Fossils Give Us a View of Past Life


Earth formed 4.6 to 4.5 billion years ago but it was 600 million years or more before life evolved. – Life arose by chemical evolution. – Molecules that could reproduce themselves

were critical. – Biological molecules were then enclosed in

membranes, forming cells. The history of Earth can be pictured as a 30-day

month…

Life arose from non-life via chemical evolution

Figure 1.8 Life’s Calendar

Each day represents 150 million years

Homo sapiens arose in the last 5 minutes of day 30 (~500,000 years ago)


For 2 billion years, life consisted of single cells called prokaryotes. – These cells were in the oceans, protected

from UV radiation, little or no oxygen (O2) in the atmosphere, no protective ozone (O3) layer.

Photosynthesis evolved about 2.5 billion years ago. – This process transforms sunlight energy

into biological energy. – Early photosynthetic cells were probably

similar to cyanobacteria.


Consequences of photosynthesis: – O2 accumulated in the atmosphere – Aerobic metabolism began • Ozone layer formed, which allowed organisms

to live on land.

Eukaryotic cells evolved from prokaryotes. – These cells have intracellular compartments

called organelles with specialized cellular functions.

– The nucleus contains the genetic information.


Some organelles probably originated by endosymbiosis: when cells ingested smaller cells. – Mitochondria (generate cell’s energy) and

chloroplasts (conduct photosynthesis) could have originated when prokaryotes were ingested by larger eukaryotes.

Multicellular organisms arose about 1 billion years ago.

Cellular specialization: Cells became specialized to perform certain functions


An evolutionary “tree” (phylogenetic tree) illustrates the order in which populations split and eventually evolved into new species.

Systematists study the evolution and classification of organisms using the fossil record and molecular evidence.

Classification & Phylogeny

Figure 1.10 The Tree of Life

Evolutionary Classification


The three domains of life are separated by molecular techniques:

Achaea (prokaryotes)

Bacteria (prokaryotes)

Eukarya (eukaryotes)

Hierarchical Classification

Kingdom

Phylum

Class

Order

Family

Genus

Species

King

Phillip

Came

Over

For

Green

Soup

Taxonomic Categories


Each species has a distinct scientific name, a binomial:

• Genus – noun, in Caps, underlined or italicized

• Species – descriptive lower case, underlined or italicized

Example: Homo sapiens Evolution results in speciation.

Structural & functional changes can evolve within a population, but if the population is separated or isolated, differences can occur in their evolution resulting in divergence.


The tree of life is predictive.

– Placement of a new species on the tree of life immediately informs us about its biology.

– Understanding relationships among species allows biologists to make predictions about species that have not yet been studied.

• Today Systematics use comparative sequencing DNA/RNA among organisms (rRNA, Chloroplast & mitochondrial DNA) to determine relationships

What is science?

Science is learning or study concerned with demonstrable truths or observable phenomena, and characterized by the systematic application of the scientific method.

• Science is a body of knowledge • Science is a way of constructing knowledge • Science asks questions • Science looks for cause and effect • Science is tentative • Science relies on mathematics and technology

Making Sense of Science

1.3 How Do Biologists Investigate Life?

Biologists use many methods to expand our understanding of life – “how science works”

1. Discovery Science / Observation: When scientists seek out and observe living things

in nature – i.e., Astronomy Development is based on new & improved

technologies – telescopes, microscopes, etc 2. Experimentation:

Hypothesis-based science called the Scientific Method & experimental design

3. Comparative - ecosystems

Figure 1.11 Tuna Tracking

Figure 1.15 Bluefin Tuna Do Not Recognize Boundaries


• Observations – asking questions

• Questions -the why or how – do background research

• Hypotheses

• Predictions / design experiments

• Testing - the idea

• Results Analysis – measurable using math & statistics

• Conclusions – support/validation of the hypothesis

• Communicate your results

2. Experimentation • Using the Scientific Method

(hypothesis–prediction (H–P) method): is a methodical & systematic process necessary for scientific investigation, generally using the following principles:

Figure 1.12 The Scientific Method


Inductive logic leads to tentative answers or explanations called hypotheses. Piece together clues to try and come up with

most likely explanation / hypothesis

Deductive logic is used to make predictions. “If…then” statements

Experiments are designed to test the predictions.


Controlled experiments manipulate the variable that is predicted to cause differences between groups.

The variable is manipulated in an “experimental” group and the results compared with data from an unmanipulated “control” group.

Graphing Results:

MIX = Manipulated variable, Independent variable, x axis

y axis

X axis

DRY = Dependent variable, Responding variable, y axis


Independent variable: the variable being manipulated.

Dependent variable: the response that is measured.


Statistical methods help scientists determine if differences between groups are significant.

Statistical tests start with a null hypothesis: that no differences exists.

Figure 1.13 Controlled Experiments Manipulate a Variable (Part 1)

Figure 1.13 Controlled Experiments Manipulate a Variable (Part 2)


3. Comparative experiments look for differences between samples or groups.

The variables can not be controlled; data are gathered from different sample groups and compared.

Figure 1.14 Comparative Experiments Look for Differences among Groups


Statistical methods are applied to data to determine the probability of getting a particular result even if the null hypothesis is true.

Statistical methods eliminate the possibility that results are due to random variation.

A scientific theory therefore describes a higher level of understanding that ties "facts" together. A scientific theory stands until proven wrong -- it is never proven correct.


Distinguishing science and nonscience:

Scientific hypotheses must be testable, and have the potential of being rejected.

Science depends on evidence that comes from reproducible and quantifiable observations.

1.4 How Does Biology Influence Public Policy?

Biological knowledge allows advances in human pursuits such as medicine and agriculture.

These advancements can raise ethical and policy questions.

1.4 How Does Biology Influence Public Policy?

Biological knowledge contributes to our understanding of human influences on our environment.

Biologists are called on to advise governments making policy decisions.

Documents

Fundamentals of Biology Valencia College BSC1010Cnickguthrie.com/omeka/archive/files/1fee345b4dcc40246c62ca701c1d04...All cells in a multicellular organism have the same genome. Figure