Biology

The Study of Life

What is Biology in the 21st Century?

How is studying Biology different today than in the past?

How does studying Biology affect your life? Why should you take this class?

How has advancement in science benefited humanity?

Course Topics• Unit 1 – Nature of Science• Unit 2 – Intro to Biology

– Biology 21st century– Chemistry of Life– Cell Structure – Classification and the Tree of Life– Biodiversity– Microscopes

• Unit 3 – Intro to Evolution– Darwin and Natural Selection– Macro and Micro evolution– Systematic Taxonomy– Phylogeny

• Unit 4 – Intro to Molecular Biology– History of Life– Organic molecules– Cell membrane transport– Energy Flow and thermodynamics

• Unit 5 – DNA Structure and Function– Nucleic Acids– DNA to Proteins– Biotechnology

• Unit 6 – Reproduction and Development– Mitosis and cloning– Meiosis– Sexual Reproduction– Comparative strategies

• Unit 7 – Genetics– Mendelian inheritance– Chromosomes– Mechanisms of evolution– Speciation

• Unit 8 – Ecology– Populations– Ecosystems– Succession– Symbiosis– Behavior

Earth supports an amazing diversity of life

biosphere = everywhere life exists

Earth supports an amazing diversity of life

• Every part of the biosphere is connected with every other part. • The biosphere includes many environments.• Biodiversity increases at the equator and decreases toward the

poles

Earth supports an amazing diversity of life

1. All levels of life have systems of related parts2. Structure and function are interdependent in Biology3. All life maintains homeostasis to survive in diverse

environments4. Evolution explains the unity and diversity of life

• Nothing in Biology makes sense except in the light of evolution.

Earth supports an amazing diversity of life • A biological species is defined as a group

of individuals that will breed to reproduce. – Scientists have described over 1.7

million of the world's species of animals, plants and algae, as of 2010.

• Mammals make up one of the smallest groups, with just 5,490 members.

• Altogether the earth's oceans, lakes, continents and islands support over 62,000 identified species of vertebrate animals and 320,000 species of plants.

A small sample of biological diversity

Earth supports an amazing diversity of life • So...how many are there?• According to a new report co-

authored by Derek Tittensor at UNEP's World Conservation Monitoring Centre (UNEP-WCMC), in Cambridge, UK, the estimate is around 8.7 million.– 86% of all species on land and

91% of those in the seas have yet to be discovered, described or catalogued.

All organisms share certain characteristics.• Biology is the scientific study of all forms of life

Life’s basic characteristic is a high degree of order

• An organism is any individual living thing.

– All are made of one or more cells.

– All need energy for metabolism.

What does all life have in common?

– All are made of one or more cells.

– All respond to their environment.– All have DNA that they pass on to offspring.

Properties of Life

cellular structure

Microscope

• Hooke (1665) English, observed cork- dead plant material, 30x, “cells”

• Leeuwenhoek (Dutch), observed pond water, 300x, 1st living cells “animacules”, protists, sperm, blood

Cell Theory Schleiden Schwann Virchow

a) All living things consist of cells.b) Cells are an organism’s basic unit of structure and

function. c) All cells come from other cells.

Metabolism Energy Utilization

Energy Flow

• Activities of life require work

• Work depends on sources of energy

• Energy exchange between an organism and environment often involves energy transformations

• In transformations, some energy is lost as heat

• Energy flows through an ecosystem, usually entering as light and exiting as heat

Sunlight

Ecosystem

Heat

Heat

Chemicalenergy

Consumers(including animals)

Producers(plants and otherphotosynthetic

organisms)

Respond to their environment Respond to their environment

Interaction With Environmentand Energy FlowOrganisms are open systems

The dynamics of an ecosystem include two major processes

• Cycling of nutrients, in which materials acquired by plants eventually return to the soil

• The flow of energy from sunlight to producers to consumers

reproduction

Heredity

The genetic material: DNA

DNA (deoxyribonucleic acid) • The substance of genes-

instructions to make protein and protein makes the organism what it is.

• Units of inheritance passed from parents to offspring.

• Double stranded molecule made of 4 nucleotides (ATGC).

• Human genome is 6 billion nucleotides long in 23 pairs of chromosomes.

Growth and Development

Unifying Themes in Biology

1. All levels of life have systems of related parts2. Structure and function are interdependent in

Biology3. All life maintains homeostasis to survive in diverse

environments4. Evolution explains the unity and diversity of life

• Nothing in Biology makes sense except in the light of evolution.

Biological organization is based on a hierarchy of structural levels

Ecosystems

The biosphere

Organisms

Populations

Communities

Cells

Organelles

Molecules

Tissues

Organs and organ systems

Cell1 µm

Atoms

10 µm

50 µm

SYSTEMS and Emerging Properties• Each level, ATOM to the BIOSPHERE, is organized.• Unique properties are revealed at each level- they

“emerge”• Properties result from interactions between the

components.• “The total is greater than the sum of it’s parts”… a

hammer functions because of it’s head and handle- together.

• Example: Social interactions are affected by the interaction of chemicals in the brain.

Form fits function

Homeostasis

Evolutionary Adaptation

Evolution

• Evolution is the core theme of biology.• Evolution accounts for life’s unity and

diversity• Implies that all living things are related.• The common ancestors are prokaryotes

that existed 3.5 billion years ago.

Evolution

– unity: all species descended from a common ancestor

– diversity: modifications that evolved as species branched from their common ancestors

Unity in the Diversity of Life

• Underlying life’s diversity is a striking unity, especially at lower levels of organization

• In eukaryotes, unity is evident in details of cell structure

Cilia of windpipe cellsCilia of Paramecium

15 µm 5 µm

Can you explain the architecture of eukaryotic cilia?

Is evolutionary adaptation a product of natural selection?

• Thomas Malthus: organisms will produce more offspring than can be supported with available resources.

• Survival of the fittest- fitness is measured by reproductive success.

• Many related organisms have similar features adapted for specific ways of life.

• Such kinships connect life’s unity and diversity to descent with modification.

• Natural selection eventually produces new species from ancestral species.

Thomas Malthus (1766-1834)

Observations:a.)Individual variation.b.)Struggle for existence.

Inference: a.)Differential reproductive success.b.)Evolutionary adaptation

The evolutionary view of life came into sharp focus in 1859, when Charles Darwin published On the Origin of Species by Natural Selection

“Darwinism” became almost synonymous with the concept of evolution

DarwinThe Concept of Natural Selection.

Charles Darwin (1809–1882)

• The Origin of Species articulated two main points

• Descent with modification (the view that contemporary species arose from a succession of ancestors)

• Natural selection (a proposed mechanism for descent with modification)

DarwinThe Concept of Natural Selection

Adaptation

• Natural selection is often evident in adaptations of organisms to their way of life and environment

• Bat wings are an example of adaptation

Diversification of finches on the Galápagos Islands

Scientific Inquiry

• Science “to know”• Has limits – only what can be observed and measured.• Can’t prove – only disprove• Must be able to test (hypotheses)• Experimental results must be repeatable• Utilizes modeling to represent ideas

Scientific Inquiry• Inquiry is a search for information and explanation,

often focusing on specific questions• The process of science blends two main processes of

scientific inquiry:– Hypothesis-based science attempts to seek natural

causes and explanations of observations– Proposes a possible explanation and tests its

validity– Discovery science describes nature through careful

observation and data analysis– Example of discovery science: understanding cell

structure

Idealized version of Scientific Process

Where does it begin?

– Observation is the active acquisition of information from a primary source. In living beings, observation employs the senses.

– Your assignment• Observe the object at your table• Use your senses to describe the object.• In your notebook, write a minimum of one page

describing the object in front of you.• You may not use the following terms in your writing

– Plant, flower, leaf, petal, stem, stalk

Theory

• Comprehensive explanation supported by abundant evidence.• Newton, Einstein, Darwin• Gravity, Relativity, Natural Selection

• Idea that ties together observations and experimental results that previously seemed unrelated.

Science, Technology & Society

• The goal of science is to understand natural phenomena

• Technology applies scientific knowledge for some specific purpose

• Research feeds technology and vice versa.

Data

• Data are recorded observations• Two types

– Quantitative data: numerical measurements– Qualitative data: recorded descriptions

• Inductive reasoning involves generalizing based on many specific observation

Science is a social process

David Reznick conducting field experiments on guppy evolution in Trinidad

Paul Serrano is digging into the past

Behavioralist Jane Goodall recording observations on chimpanzees

Science, Technology & Society

Energy

Structure to function

Interdependence

Dilemma: How to study Biology?

– something complex such as an organism or cell cannot be analyzed without taking it apart.

– If you take something apart it disrupts the system and interferes with the meaningful understanding of how it works.

Dilemma: How to study Biology?• Systems Biology

– seeks to understand the behavior of a whole system rather than its parts

– Seeks to create models of the dynamic behavior of whole biological systems

– An example is a systems map of how proteins interact in a fruit fly cell. The model may predict how a change in one part of a system will affect the rest of the system.

Systems biology uses three key research developments:

– High-throughput technology: methods to generate large data sets rapidly

– Bioinformatics: using computers and software to process and integrate large data sets

– Interdisciplinary research teams