exploring life copyright cmassengale1. themes help to organize biological information copyright...

Exploring LifeExploring Life

copyright cmassengale 1

Themes Help to Organize Biological

information


Unifying Themes in Unifying Themes in BiologyBiology

Evolution~ biology’s core theme; differential reproductive success

Emergent Properties~ hierarchy of life (new properties at each level)

The Cell~ all organism’s basic structure

Heritable Information~ DNA Structure & Function~ form and

function (Form determines function)

Environmental Interaction~ organisms are open systems

Regulation~ feedback mechanisms

Unity & Diversity~ universal genetic code

Scientific Inquiry~ observation; testing; repeatability


1 µmOrganelles

Nucleus (contains DNA)

Cytoplasm

Membrane

DNA(no nucleus)

MembraneEukaryotic cell

Prokaryotic cell


Life can be divided into

different levels of biological

organization


The biosphere

Communities

Populations

Organisms

Ecosystems

Organs and organ systems

Cells

Cell

Organelles

Atoms

Molecules

Tissues

10 µm

1 µm

50 µm


The biosphere

Communities

Populations

Organisms

Ecosystems


Organs and organ systems

Cells

Cell

Organelles

Atoms

Molecules

Tissues

10 µm

1 µm

50 µm


Hierarchy of OrganizationHierarchy of Organization

MoleculeOrganelleCellsTissuesOrganSystemsOrganism


Macromolecules Macromolecules

Carbohydrates (CHO) - energyLipids (CHO) – long term energyProteins (CHON) – building &

workNucleic acids (CHONP) – genetic

information


Feedback Regulation: Feedback Regulation: NegativeNegative

Accumulation of an end product of a process slows that process

Example: sugar breakdown generates ATP; excess ATP inhibits an enzyme near the beginning of the pathway


Feedback Regulation: Feedback Regulation: PositivePositive

An end product speeds up its production

Example: blood clotting in response to injury


The Process of ScienceThe Process of Science

Scientific MethodDeductive

reasoning“If….then” LogicHypothesis

(testable)Theory (widely

tested & accepted)Law (proven)


Properties of Living Properties of Living ThingsThings

Paramecium Bacteriophage

Which is considered living? Why?


Early Views of LifeEarly Views of Life

Vitalism: The insistence that there is some big, mysterious extra ingredient in all living things

Led to idea of spontaneous generation (life can come from nonliving material) Flies came from dead animals Mice came from Hay


Idea was challenged by scientist Francesco Redi in 1698.

Designed an experiment where 3 jars contained meat.

The Redi ExperimentThe Redi Experiment


Setup 1Setup 1

One Jar contained meat and had an open top which would allow the passage of flies. (maggots would appear on the

meat)copyright cmassengale 17

Setup 2Setup 2

The second jar was covered with an airtight lid not allowing the passage of flies. (no maggots would appear on the

meat) copyright cmassengale 18

Setup 3Setup 3

The third was covered by a screen allowing passage of eggs, but not flies. (few maggots would appear on

meat)


ConclusionConclusion

Since the third setup would theoretically allow the passage of “ethers”, but no maggots appeared, it was implied that flies were the source of the maggots. (Deductive Reasoning) Led to the theory of Biogenesis

All life comes from preexisting life


Life is Recognized by What Living

Things Do


Order

Evolutionary adaptation

Responseto theenvironment

ReproductionGrowth

anddevelopment

Energyprocessing

Regulation


PROPERTIES of LIFEPROPERTIES of LIFE

Be made of Cells.The Cell is the basic unit of life

Is self contained and possesses a barrier (membrane) which separates itself from the environment.

Two types of organisms. Unicellular - One celled organism (Uni=1) Multicellular - Many cells (Multi=”many”)


CellsCells

The cell is the lowest level of organization that can perform all activities required for life

All cells: Are enclosed by a membrane Use DNA as their genetic information

The ability of cells to divide is the basis of all reproduction, growth, and repair of multicellular organisms



Living Things must Reproduce.Must be able to create more of it’s own kindTwo types of reproduction:

Sexual - Two parent organisms combine genetic material to produce the offspring.

Asexual - When a single organism can divide or “bud” to create it’s offspring without another of it’s species.



Living things ALL Have DNA. Universal Genetic CodeInstructions for making all the

bodies proteinsLocated in the nucleus

(eukaryotes) or nucleiod region (prokaryotes)


DNADNA

Chromosomes contain most of a cell’s genetic material in the form of DNA (deoxyribonucleic acid)

DNA is the substance of genesGenes are the units of inheritance that

transmit information from parents to offspring

27copyright cmassengale

Each chromosome has one long DNA molecule with hundreds or thousands of genes

DNA is inherited by offspring from their parents

DNA controls the development and maintenance of organisms


NucleicontainingDNA

Sperm cell

Egg cell

Fertilized eggwith DNA fromboth parents

Embryo’s cells withcopies of inherited DNA

Offspring with traitsinherited fromboth parents


Each DNA molecule is made up of two long chains arranged in a double helix

Each link of a chain is one of four kinds of chemical building blocks called nucleotides (A,T,C,G)


Nucleus

DNA

Cell

Nucleotide

(a) DNA double helix

(b) Single strand of DNA


Genes control protein production indirectly

DNA is transcribed into RNA then translated into a protein

An organism’s genome is its entire set of genetic instructions


PROPERTIES of LIFEPROPERTIES of LIFELiving things must Grow & Develop.Growth refers to two processes.

Increase in the number of cells. Increase in the size of cells.

Development refers to changes in the organism which occur through it’s life-span. Includes cell differentiation. Includes organ development Includes aging & death.



Living things obtain & use energy.Energy is used by all living things for

growth, development & reproduction. Life processes which result in “building”

the organism ia known as Anabolism. (endergonic-store energy)

Life process where energy is extracted by “breaking-down” substances is called Catabolism. (exergonic-release energy)

ATP – cellular energy


PROPERTIES of LIFEPROPERTIES of LIFE Living things must Respond (or react) to their

environment in some way. Something which causes an organism to react is

known as a Stimulus (stimuli). The ability of an organism to react is called

Irritability. Most responses are geared for maintaining

Homeostasis. Homeostasis is a process where an organism

maintains a stable internal environment so life can continue.

Some examples include temperature, pH, and water content of the cell.


Organisms Interact with Their Organisms Interact with Their EnvironmentsEnvironments

Every organism interacts with its environment, including nonliving factors and other organisms

Both organisms and their environments are affected by the interactions between them For example, a tree takes up water and

minerals from the soil and carbon dioxide from the air; the tree releases oxygen to the air and roots help form soil


Ecosystem DynamicsEcosystem Dynamics

The dynamics of an ecosystem include two major processes: Cycling of nutrients, in which materials

acquired by plants eventually return to the soil (Carbon, Phosphorus, Water, Nitrogen)

The flow of energy from sunlight to producers to consumers


Sunlight

Ecosystem

Heat

Heat

Cyclingof

chemical

nutrients

Producers(plants and

other photosyntheti

corganisms)

Chemical energy

Consumers(such as animals)


Evolution unifies biology at different

scales of size throughout the

history of life on Earth


Diversity of LifeDiversity of Life

Approximately 1.8 million species have been identified and named to date, and thousands more are identified each year

Estimates of the total number of species that actually exist range from 10 million to over 100 million


Grouping SpeciesGrouping Species

Taxonomy is the branch of biology that names and classifies species into groups of increasing breadth

Domains, followed by kingdoms, are the broadest units of classification


Species

Genus

Family

Order Class Phylum

Kingdom

Domain

Ursus americanus(American black bear)

Ursus

Ursidae

Carnivora

Mammalia

Chordata

Animalia

Eukarya


The Three Domains of LifeThe Three Domains of Life

The three-domain system is currently used, and replaces the old five-kingdom system

Domain Bacteria and domain Archaea comprise the prokaryotes

Domain Eukarya includes all eukaryotic organisms


(a) DOMAIN BACTERIA

(b) DOMAIN ARCHAEA

(c) DOMAIN EUKARYA

Protists

Kingdom Fungi

KingdomPlantae

Kingdom Animalia 44copyright cmassengale

DOMAIN BACTERIA


DOMAIN ARCHAEA46copyright cmassengale

EukaryaEukarya

The domain Eukarya includes four kingdoms: Protista (unicellular) Fungi (mostly multicellular) Plantae (multicellular) Animalia (multicellular)


(c) DOMAIN EUKARYA

Protists

Kingdom Fungi

Kingdom Plantae

Kingdom Animalia


Protists


Kingdom Fungi 50copyright cmassengale

Kingdom Plantae


Kingdom Animalia


Fossils and other evidence document the evolution of life

on Earth over billions of years


Natural SelectionNatural Selection

Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859

Darwin made two main points: Species showed evidence of “descent with

modification” from common ancestors Natural selection is the mechanism behind

“descent with modification” Darwin’s theory explained the duality of

unity and diversity



Descent with Modifications

Darwin observed that: Individuals in a population have traits

that vary Many of these traits are heritable

(passed from parents to offspring) More offspring are produced than survive Competition is inevitable Species generally suit their environment


Darwin inferred that: Individuals that are best suited to their

environment are more likely to survive and reproduce

Over time, more individuals in a population will have the advantageous traits

In other words, the natural environment “selects” for beneficial traits


Populationwith variedinherited traits.

Eliminationof individualswith certaintraits.

Reproductionof survivors.

Increasingfrequencyof traits that enhance survival and reproductive success.

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

Bat wings are an example of adaptation


The Tree of LifeThe Tree of Life

“Unity in diversity” arises from “descent with modification” For example, the forelimb of the bat,

human, horse and the whale flipper all share a common skeletal architecture

Fossils provide additional evidence of anatomical unity from descent with modification


Darwin proposed that natural selection could cause an ancestral species to give rise to two or more descendent species For example, the finch species of the

Galápagos IslandsEvolutionary relationships are often

illustrated with tree-like diagrams that show ancestors and their descendents


COMMONANCESTOR

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Green warbler finch Certhidea olivaceaGray warbler finch Certhidea fuscaSharp-beakedground finch Geospiza difficilisVegetarian finch Platyspiza crassirostrisMangrove finch Cactospiza heliobatesWoodpecker finch Cactospiza pallidaMedium tree finch Camarhynchus pauperLarge tree finch Camarhynchus psittaculaSmall tree finch Camarhynchus parvulusLarge cactusground finchGeospiza conirostris

Cactus ground finchGeospiza scandens

Small ground finchGeospiza fuliginosaMedium ground finchGeospiza fortisLarge ground finchGeospiza magnirostris

Gro

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exploring life copyright cmassengale1. themes help to organize biological information copyright...

Documents

copyright cmassengale8

copyright cmassengale14

copyright cmassengale6

z idea

conclusion z

living things z

passage of flies

y maggots