Species Transplants

• Species transplants include organisms that are intentionally or accidentally relocated from their original distribution

• Species transplants can disrupt the communities or ecosystems to which they have been introduced

1

Behavior and Habitat Selection

• Some organisms do not occupy all of their potential range

• Species distribution may be limited by habitat selection behavior

2

Life history traits are products of natural selection

• An organism’s life history comprises the traits that affect its schedule of reproduction and survival:– The age at which reproduction begins

– How often the organism reproduces

– How many offspring are produced during each reproductive cycle

• Life history traits are evolutionary outcomes reflected in the development, physiology, and behavior of an organism

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Fig. 53-8

MaleFemale

100

RESULTS

80

60

40

20

0Reduced

brood sizeNormal

brood sizeEnlarged

brood sizePare

nts

surv

ivin

g th

e fo

llow

ing

win

ter (

%)

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Many factors that regulate population growth are density dependent

• There are two general questions about regulation of population growth:– What environmental factors stop a population from

growing indefinitely?– Why do some populations show radical fluctuations

in size over time, while others remain stable?

5

Fig. 53-17

(a) Cheetah marking its territory

(b) Gannets 6

Gross and Net Primary Production

• Total primary production is known as the ecosystem’s gross primary production (GPP)

• Net primary production (NPP) is GPP minus energy used by primary producers for respiration

• Only NPP is available to consumers• Ecosystems vary greatly in NPP and contribution

to the total NPP on Earth• Standing crop is the total biomass of

photosynthetic autotrophs at a given time

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Primary Production

• All ecosystems are restricted by limiting factors which is a reduction or absence in a needed reactant for the producer to grow and photosynthesize

• Light Limitation• Nitrogen and phosphorous are typically the nutrients that most often limit production

8

Minimum Viable Population Size

• Minimum viable population (MVP) is the minimum population size at which a species can survive

• The MVP depends on factors that affect a population’s chances for survival over a particular time

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Case Study: Analysis of Grizzly Bear Populations

• One of the first population viability analyses was conducted as part of a long-term study of grizzly bears in Yellowstone National Park

• This grizzly population is about 400, but the Ne is about 100

• The Yellowstone grizzly population has low genetic variability compared with other grizzly populations

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Bioremediation

• Bioremediation is the use of living organisms to detoxify ecosystems

• The organisms most often used are prokaryotes, fungi, or plants

• These organisms can take up, and sometimes metabolize, toxic molecules

11

Fig. 56-22a

(a) Unlined pits filled with wastes containing uranium12

Quorum sensing

• describes the bacterial communication between cells that allows them to recognize and react to the size of their surrounding cell

13

Quorum sensing

14

Operons: The Basic Concept

• A cluster of functionally related genes can be under coordinated control by a single on-off “switch”

• The regulatory “switch” is a segment of DNA called an operator usually positioned within the promoter

• An operon is the entire stretch of DNA that includes the operator, the promoter, and the genes that they control

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• The operon can be switched off by a protein repressorThe repressor prevents gene transcription by binding to

the operator and blocking RNA polymeraseThe repressor is the product of a separate regulatory gene

• The repressor can be in an active or inactive form, depending on the presence of other molecules

A corepressor is a molecule that cooperates with a repressor protein to switch an operon off

For example, E. coli can synthesize the amino acid tryptophan

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The Chemical Groups Most Important in the Processes of Life

• Functional groups are the components of organic molecules that are most commonly involved in chemical reactions

• The number and arrangement of functional groups give each molecule its unique properties

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings17

Fig. 4-9

Estradiol

Testosterone

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Apoptosis (programmed cell death) integrates multiple cell-signaling pathways

• Apoptosis is programmed or controlled cell suicide

• A cell is chopped and packaged into vesicles that are digested by scavenger cells

• Apoptosis prevents enzymes from leaking out of a dying cell and damaging neighboring cells

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings19

Fig. 11-19

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LUCA

• Protobionts are aggregates of abiotically produced molecules. They are not capable of precise reproduction, but they maintain an internal chemical environment different from their surroundings and exhibit some of the properties associated with life, including metabolism and excitability.

21

LUCA

• Last Universal Common Ancestor• In a nutshell, the study of LUCA broadly

revolves around two questions:• What features are common to all cellular life?

What makes the three domains — archaea, bacteria and eukaryotes — apart from one another

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• Taq PolymeraseGram positive negativeHaophiles, Thermophiles, Chemophiles 3 kingdomsAntibiotic resistance 1. quick reproduction (20 min) & mutations, 2-4. genetic recombination (transduction, conjugation, transformationResistance MRSAIndependent/dependent variablespromoter in replicationmethylationphosphorylationwater potenitalJET LAGxyllum ploeym

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• Unit 8• C5130&31, C53 28&32, 63&70C55

17&21/22/23C56 44&47, 85&88C18 6&7/8C4 30&31

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