Chapter 13: Life in the Ocean - PowerPoint Presentation

Slide1

Chapter 13:Life in the OceanSlide2

Main Concepts

All of Earth

’

s life-forms are related. All have apparently evolved from a single ancient instant of origin.

Evolution happens.

Organisms change as time passes, adapting by natural selection to their environments. Oceanic life is classified by evolutionary heritage.

All life activity is involved, directly or indirectly, in energy transformation and transfer.

Primary productivity involves the synthesis of organic materials from inorganic substances by photosynthesis or chemosynthesis. Primary productivity is expressed in grams of carbon bound into organic material per square meter of ocean surface area per year (

gC

/m

2

/

yr

).

The atoms and small molecules that make up the

biochemicals

, and thus the bodies, of organisms move between the living and nonliving realms in biogeochemical cycles. An organism

’

s success can be limited by inappropriate amounts of these materials and the physical and biological conditions surrounding the organism.

The success of marine organisms depends on their relation with the physical and biological factors that influence them. Rapid change may result in mass extinction.Slide3

Life on Earth Is Notable for Its Unity and Its Diversity

Life on Earth exhibits unity and diversity:

diversity

because Earth may house as many as 100 million different species (kinds) of living organisms;

unity

because all species share the same underlying mechanisms for capturing and storing energy, manufacturing proteins, and transmitting information between generations.

In a sense, all life on Earth is fundamentally the same

-

it

’

s just packaged in thousands of different ways.

Earth

’

s organisms have changed, or

evolved

, over more than 4 billion years.Slide4

Evolution Appears to Operate by Natural Selection

Evolution occurs through the process of

natural selection.

In any group of organisms, more offspring are produced than can survive to reproductive age.

Random variations occur in all organisms. Some of these traits are inheritable.

Some inheritable traits make an organism better suited to its environment (most do not).

Because bearers of favorable traits are more likely to survive, they are also more likely to reproduce successfully than bearers of unfavorable traits.

The physical and biological (natural) environment itself does the selection. Slide5

Evolution Appears to Operate by Natural Selection

Evolution by natural selection is the accumulation of beneficial inheritable traits, known as

adaptations

.

A

species

is a group of actually (or potentially) interbreeding organisms that is reproductively isolated from all other forms of living things.

Because

conditions in the open ocean are relatively uniform, large marine animals with similar lifestyles but different evolutionary heritages eventually tend to look much the same. This is known as

convergent evolution

.Slide6

Systems of Classification May Be Artificial or Natural

The study of biological classification is called

taxonomy

.

(RIGHT) Carolus Linnaeus invented three supreme categories, or

kingdoms

: animal, vegetable, and mineral. Today

’

s biologists leave the mineral kingdom to the geologists and have expanded Linnaeus

’

s two living kingdoms to six.Linnaeus’s great contribution was a system of classification based on hierarchy, a grouping of objects by degrees of complexity, grade, or class.Slide7

A family tree showing the relationship of the three domains that presumably evolved from a distant common ancestor.

The Bacteria and Archaea contain single-celled organisms without nuclei or organelles; collectively, they are called

prokaryotes

.

The fungi, protists, animals, and plants contain organisms with cells having nuclei and organelles; collectively, they are called

eukaryotes

.

Systems of Classification May Be Artificial or NaturalSlide8

The modern system of biological classification, using the California gull (Larus californicus) as an example. Note the boxes-within-boxes approach, a hierarchy.

Systems of Classification May Be Artificial or NaturalSlide9

The Flow of Energy Allows Living Things to Maintain Complex Organization

What distinguishes life from non-life is the ability of living things to capture, store, and transmit

energy

-

and the ability to reproduce.

Energy can be stored by photosynthesis or chemosynthesis.

Photosynthesis

is the process used by most producers to convert the sun

’

s energy to food energy.

Chemosynthesis

is the production of food from inorganic molecules in the environment.Slide10

A comparison of photosynthesis and chemosynthesis

The Flow of Energy Allows Living Things to Maintain Complex OrganizationSlide11

The flow of energy through living systems. At each step, energy is degraded (that is, transformed into a less useful form).

The Flow of Energy Allows Living Things to Maintain Complex OrganizationSlide12

Primary Producers Synthesis Organic MaterialsPhytoplankton

are responsible for producing between 90% and 96% of the surface ocean

’

s carbohydrates.

Seaweeds

contribute from 2% to 5% of the ocean’s primary productivity.

Chemosynthetic organisms probably account for between 2% and 5% of the total productivity in the water column.

The synthesis of organic materials from inorganic substances by photosynthesis or chemosynthesis is called

primary productivity

.Slide13

Global Primary ProductivityOceanic productivity can be observed from space. NASA

’

s

SeaWiFS

satellite can detect the amount of chlorophyll in ocean surface water. Chlorophyll content allows an estimate of productivity. Red, yellow, and green areas indicate high primary productivity; blue areas indicate low. Slide14

Food Webs Disperse Energy through Communities

Autotrophs –

organisms that make their own food, also called

producers

.

Heterotrophs –

organisms that must consume other organisms for energy

Trophic pyramid –

a model that describes who eats whom

Primary consumers –

these organisms eat producers

Secondary consumers –

these organisms eat primary consumers

Top consumers –

the top of the tropic pyramidSlide15

A generalized trophic pyramid. How many kilograms of primary producers is required for an average tuna sandwich? Using the trophic pyramid model shown here, you can see that 1 kilogram of tuna (enough to make ten 1/4-pound tuna sandwiches) at the fifth trophic level (the fifth feeding step of the pyramid) is supported by 10,000 kilograms of phytoplankton at the first level.

Food Webs Disperse Energy through CommunitiesSlide16

Diatoms, and other primary producers, convert the energy from the sun into food used by the rest of the oceanic community.

A

simplified

food web

, illustrating the major trophic relationships leading to an adult blue whale.

Food Webs Disperse Energy through CommunitiesSlide17

Living Organisms Are Built from a Few Elements

Carbon

- present in all organic molecules

Nitrogen

- found in proteins and nucleic acids

Phosphorus and silicon –

found in rigid parts of organisms

Iron and trace metals -

used for electron transport

The atoms and small molecules that make up the

biochemicals

, and thus the bodies, of organisms move between the living and nonliving realms in

biogeochemical cycles

. Slide18

The Carbon Cycle Is Earth’s Largest Cycle

The

Carbon

Cycle

Because of its ability to form long chains to which other atoms can attach, carbon is considered the basic building block of all life on Earth. Slide19

Nitrogen Must Be “Fixed” to Be Available to Organisms

The Nitrogen Cycle.

The atmosphere

’

s vast reserve of nitrogen cannot be assimilated by living organisms until it is

“

fixed

”

by bacteria and cyanobacteria, into a biologically available form. Nitrogen is an essential element in the construction of proteins, nucleic acids, and a few other critical

biochemicals. Slide20

Physical and Biological Factors Affect the Functions of an Organism

A

limiting factor

is a factor found in the environment that can be harmful if present in quantities that are too large or too small.

Any factor required for life can become a limiting factor.

Any aspect of the physical environment that affects living organisms is a

physical factor.

The most important physical factors for marine organisms:

Light, dissolved gases, temperature, salinity

Acid-base balance, hydrostatic pressure, nutrientsSlide21

Biological factors

also affect living organisms in the ocean.

Some biologic factors that affect ocean organisms:

Feeding relationships

Crowding (competition for space)

Metabolic wastes

Defense of territory

Physical and Biological Factors Affect the Functions of an OrganismSlide22

Environmental Factors Influence the Success of Marine Organisms

The

depth to which light penetrates is limited by the number and characteristics of particles in the water.

The upper, sunlit zone of the ocean is known as the

photic zone

.

In the

euphotic zone

, there is enough light for photosynthesis.

Below that depth, in the

disphotic

zone

, light may be present, but not enough to produce net glucose.

The

aphotic zone

lies in permanent darkness. Slide23

Temperature Influences Metabolic Rate

The ocean temperature varies with depth and latitude.

The rate at which chemical reactions occur in an organism is largely dependent on heat.

(LEFT) Temperatures of marine waters capable of supporting life.

Some areas of the ocean, such as hydrothermal vents, may support specialized living organisms at temperatures of up to 400

°

C (750

°

F)!Slide24

Substances Move through Cells by Diffusion, Osmosis, and Active TransportMarine organisms rely on these processes for many functions.

Diffusion

is mixing due to random molecular movements.

Osmosis

is diffusion of water through a membrane.

Active transport

is the transport of a substance against a concentration gradient. Active transport requires energy input.

(LEFT) The effects of osmosis in different environments.

(a)

An isotonic solution

. Cells placed in isotonic solutions do not change size since there is no net movement of water. (b) A hypertonic solution. A cell placed in a hypotonic solution will shrink. (c) A hypotonic solution. A cell placed in a hypotonic solution will swell. Slide25

The Marine Environment Is Classified into Distinct ZonesScientists divide the marine environment into

zones

, areas with homogeneous physical features.

Zones are classified by location and the behavior of the organisms found there.