Themes of Biology Lecture Outline

• Defining life by properties of being alive (7)

• Order of structural hierarchy levels of the living world

– Ascending/up & descending/down

– emergent properties

• Unifying themes

– Form and function

– Cell Theory & types of cells

– Genetic material- DNA

– Scientific Method and approaches

Biological Themes Learning Objectives & Major concepts

• Identify the properties of living things – Learn and explain

• The structural level of organization of the living world • Emergent properties, homeostasis, feedback regulation • Interaction of living organisms within the ecosystem & flow of energy

and recycling of matter • Evolution as a central theme of biology (Natural selection leads to

adaptation of populations and evolution of new species)

• Understand and explain the unifying themes of Biology : – Form or structure dictates function at all levels of the biological

hierarchy – Cell theory & two types of cells: Prokaryotic & Eukaryotic – DNA as the genetic material (information) of all living cells on earth – The Scientific Method and approaches to studying of biology:

reductionism & systems biology

Properties of Living Organisms (1) Order

(2) Reproduction

(3) Growth and development

(4) Energy processing

(7) Evolutionary adaptation

(6) Regulation

(5) Interact with the environment

Properties of Living Organisms • Order • Reproduction • Growth and development • Energy processing or transformation • Interaction with environment • Regulation of internal conditions –Homeostasis • Evolutionary adaptation

• Ordered organization of the living world o Levels of structural hierarchy o ascending vs. descending- o emergent properties

Regulation of internal conditions- Homeostasis

Biological processes are self-regulating by feedback mechanisms

1. Negative feedback

2. Positive feedback

Living organisms interact with their environment transforming energy

Decomposers

Living organisms interact with their environment transforming energy

Ecosystem

Sunlight Producers (such as plants)

Consumers (such as animals)

Heat

O2 O2

CO2

Chemical energy (food)

CO2

Water and minerals taken up by tree roots

Cycling of chemical nutrients

Decomposers (in soil)

Figure 1.4 Ecosystem

Sunlight

CO2

Heat

Chemical energy (food)

Producers (such as plants)

Water and minerals taken up by tree roots

Cycling of chemical nutrients

Decomposers (in soil)

Consumers (such as animals)

CO2

O2 O2

Sperm cell

Nuclei containing DNA

Egg cell

Fertilized egg with DNA from both parents

Embyro’s cells with copies of inherited DNA

Offspring with traits inherited from both parents

Growth & Development

Unspecialized cells

Different specialized

cells

Evolutionary Adaptation of populations Populations: groups of organisms belonging to the

same species

Populations • Genetic diversity • Under influence of external factors • Differential reproductive success (Natural Selection)

Populations adapt to their surrounding and evolve

Evolutionary Adaptation – Charles Darwin

How evolution really works http://www.pbs.org/wgbh/evoluti

on/library/11/2/e_s_4.html

Levels of Order in the Living World

– Organized into structural hierarchical levels

– Ascending vs. Descending

– Each level builds on the level below it

– Interaction between components of each

level of the structural hierarchy leads to the

emergence of new properties

Atoms/Elements

Molecules

Organelle

Cell

Tissue

Organ

Organ system

Organism

Population

Community

Ecosystem

Biosphere

Chemical world

Biological World

Non-living

Living

Ascending

Descending

Viruses: organized structure of biomolecules

Figure 1.2_1

Biosphere

Madagascar

Ecosystem: Forest in

Madagascar

Community: All organisms in

the forest

Population: Group of ring-tailed

lemurs

Organism: Ring-tailed lemur

Figure 1.2_2

Organism: Ring-tailed lemur

Organ system: Nervous system

Organ: Brain

Tissue: Nervous tissue

Nerve

Spinal cord

Brain

Organelle: Nucleus

Cell: Nerve cell

Nucleus

Atom

Molecule: DNA

Emergent Properties

Biological systems are much more than the sum of their parts

Biological Themes

• Form/structure and Function • The Cell Theory & Types of cells • Genetic Material- DNA

Structure or form fits function at all levels of the biological organization

Atoms/Elements

Molecules

Organelle

Cell

Tissue

Organ

Organ system

Organism

Population

Community

Ecosystem

Biosphere

Chemical world

Biological World

Non-living

Living

Ascending

Descending

Viruses: organized structure of biomolecules

Biological Themes/ The cell Theory

• A cell is the basic unit of biological structure and function

• All cells arise from preexisting cells

Two Types of cells on earth differ in size and complexity

– Prokaryotic cells: DNA is not surrounded by a membrane

– Eukaryotic cells: membrane-enclosed organelles, including a DNA-containing nucleus

Eukaryotic cell Prokaryotic cell

Cytoplasm

DNA (no nucleus)

Membrane

Nucleus (membrane- enclosed)

Membrane

Membrane- enclosed organelles

DNA (throughout nucleus) 1 µm

Nucleus

DNA

Cell

Genetic Material/DNA

- DNA directs all cell’s activities

- Genetic information must be duplicated before any cell divides

Nucleotide

A

C

T

A

T

A

C

C

G

G

T

A

T

A

DNA

Electronic information

recognized by Player

Music is produced

Analogy

Genetic information

recognized by Cell machinery

Protein is produced