Themes of Biology

Emergence

PBS NOVA Emergence

Fig. 1-4

The biosphere

Communities

Populations

Organisms

Ecosystems

Organs and organ systems

Cells

Cell

Organelles

Atoms

MoleculesTissues

10 µm

1 µm

50 µm

Emergent Properties, Reductionism, Systems Biology

DARWIN’S THEORY OF EVOLUTION

Copyright © 2009 Pearson Education, Inc.

Fig. 1-20

Populationwith variedinherited traits.

Eliminationof individualswith certaintraits.

Reproductionof survivors.

Increasingfrequencyof traits that enhance survival and reproductive success.

4321

Terminalbud

Lateralbuds

Leaves

Kale

Stem

Brussels sprouts

Cauliflower

Cabbage

Kohlrabi

Wild mustard

Flowerclusters

Flowersand stems

Broccoli

• Note these important points – Individuals do not evolve: populations evolve– Natural selection can amplify or diminish only heritable

traits; acquired characteristics cannot be passed on to offspring

– Evolution is not goal directed and does not lead to perfection; favorable traits vary as environments change

Darwin proposed natural selection as the mechanism of evolution

Chromosome with alleleconferring resistanceto pesticide

Additionalapplications willbe less effective, andthe frequency ofresistant insects inthe populationwill grow

Survivors

Pesticide application

Humerus

Radius

Ulna

Carpals

MetacarpalsPhalanges

Human Cat Whale Bat

Pharyngealpouches

Post-analtail

Chick embryo Human embryo

Tetrapod limbs

Amnion

Lungfishes

Feathers

Amphibians

Mammals

Lizardsand snakes

2

Hawks andother birds

Ostriches

Crocodiles

1

3

4

5

6

Am

nio

tes

Tetrap

od

s

Bird

s

Cells

1 µm

OrganellesNucleus (contains DNA)

Cytoplasm

Membrane

DNA(no nucleus)

Membrane

Eukaryotic cellProkaryotic cellFig. 1-8

Order

Reproduction

Growth and Development

Energy Processing

Energy processing

Response

Regulation

Adaptation

DNA

NucleicontainingDNA

Sperm cell

Egg cell

Fertilized eggwith DNA fromboth parents

Embryo’s cells withcopies of inherited DNA

Offspring with traitsinherited fromboth parents

Fig. 1-9

Continuity of life is based on heritable information in the form of DNA

Diversity of Life

Domain Bacteria

Domain Archea

Domain Eukarya