Download Basics of Biology Chapter 4

Basics of Biology
Chapter 4
Developing
Shark
Embryo
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Four essential ingredients of life
• Carbohydrates- sugars and starches, like
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glucose- good energy source
Proteins- Made up of chains of amino acids
(have nitrogen in them)
Enzymes- proteins that speed up chemical reactions
in the body
Hormones- chemical messengers in the body
• Lipids- fats and oils, store energy- repel water
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which is useful for many marine mammals and
birds
Nucleic acids- DNA and RNA, store and transmit
genetic information for proteins
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Simple molecules
have low energy,
complex molecules
store energy in
their bonds
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Biochemical reactions
• Substances are constantly being synthesized
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(put together) and broken down to store or
release energy for living things
Photosynthesis- capturing the sun’s energy to
produce simple sugars
uses CO2, releases O2
Respiration- breaks down food (sugars) to
release energy
uses O2, releases CO2
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Algae are the main
photosynthetic
organisms in the oceanSometimes it isn’t green
due to many types of
photosynthetic pigments
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Respiration
• The sugars produced by photosynthesis are
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broken down to release energy for the cells.
Aerobic respiration- releases the most, and
needs oxygen.
Anaerobic- does not release as much energy, no
oxygen required.
-organisms that live in sediments or in the
guts of fishes.
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Which produce and which eat?
• Autotrophs- can produce their own food,
mostly algae and bacteria in the ocean
• Heterotrophs- cannot photosynthesize, all
the animals that eat other organisms
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In photosynthesis,
solar energy is
converted to chemical
energy.
-only done by
autotrophs
In respiration,
chemical energy is
released for the
organisms to use.
-both autotrophs and
heterotrophs
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Prokaryotes do not
have a nucleus- this
one is called a
cyanobacteria, it can
photosynthesize
- bacteria only!!!!!
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Eukaryotic cells
• Have a nucleus and organelles
• All the other kingdoms- plant, animal,
fungi and protists (algae and some
animal- like plankton)
• Plant cells- have a cell wall and a large
vacuole for storing water
• Animal cells- no cell walls, no large
vacuole.
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Typical animal cell- no cell wall.
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Typical plant cell- note the cell wall
and the water filled vacuole
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Levels Of Organization- least complex
to most complex
• Cell- Smallest unit of life, simplest form of
life- made of organelles which are made of
molecules
• Tissue- cells that are specific for a function
• Organ- tissue organized into structures
• Organ system- a group of organs that
work together
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Levels Of Organization- least complex
to most complex
• Individual- a single organism
• Population- a group of the same species
living in an area
• Community- several populations of
different species in the same habitat
• Ecosystem- the community AND the
physical environment
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A Sponge is a
simple animal at
the cellular level
of organization.
(No specialized
tissues or
organs)
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A population
of Mussels on
a shore in
New Zealand.
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A community of mussels, barnacles and
seaweeds
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Table 4.01
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Diffusion- movement of molecules from
High to Low concentration
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Osmosis- Diffusion of water into
and out of a cell
• This is a major physiological issue for
marine organisms!!!!
• Water will always flow towards where
there is more solute (salts)
• Marine organisms have a variety of
adaptations to be able to balance water
and salts in their bodies.
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A cell responding to changes in salinity
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Osmosis (cont’d)
• Osmoconformers- Conform to salinity. Their
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internal salt concentration varies with changes in
salinity
Osmoregulators- have special mechanisms for
maintaining a constant water/salt balance.
Most marine fishes tend to lose water, so they
compensate for this by excreting very little water
in their urine.
They also must excrete excess salts, some salts
are excreted through urine, more salts are
excreted through the gills.
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Figure 4.14a
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This Sea Turtle has glands near the
eyes that excrete salty “tears”.
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Temperature
• All animals are greatly affected by temperature.
• Temperature plays a major role in determining
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where certain organisms live in the ocean.
Ectotherms or Poikilotherms- cold- blooded
Endotherms or homeotherms- warm-blooded.
These animals expend a great amount of energy
to maintain a stable internal temperature.
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Figure 4.16
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Modes of reproduction
• Asexual reproduction
• no gametes (sperm and eggs) are used,
offspring are genetically identical to
parent.
• Examples- budding, fission, vegetative
reproduction.
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Asexual Reproduction- fission- the
two new cells are clones.
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Asexual reproduction- budding and
rhizomes (runners)
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Modes of Reproduction (cont’d)
• Sexual reproduction- combining genetic
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material of two parents to produce unique
offspring.
Sperm and Eggs (gametes) required.
Each gamete has half the number of
chromosomes required (haploid)
Upon fertilization the new individual has the
right # of Chromosomes (diploid).
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Reproductive Strategies
• Broadcast Spawning- organisms produce
millions of gametes, no further interaction
with offspring.
• Most marine species fertilize externally.
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Photos of a coral spawning and a
giant clam spawning
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Organizing Life’s Diversity
• Biologists reconstruct the history of life on earth
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is based upon a unifying concept in biologyEvolution by Natural Selection.
Natural Selection- individuals with certain traits
give them an advantage in a given environment.
These individuals will be more successful in
reproducing- ‘favorable’ traits are passed on to
offspring.
Evolution is simply the genetic change in
populations over MANY generations.
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Organizing Life (cont’d)
• Biological species concept- Populations of
organisms that have common
characteristics, and can interbreed.
• Naming - We scientifically name organisms
with two names the genus and species.
Ex.
Homo sapien,
Tursiops truncatus
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Phylogeny- reconstructing evolution
• We use a branched diagram to try and
reconstruct the evolutionary past of
groups of organisms.
• These records are constantly being revised
as we learn more about the fossil record.
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Figure 4.23
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Probable Phylogeny of the six kingdoms
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The Tree of Life
• All organisms are classified into the following
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categories:
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Eukarya
Animalia
Chordata
Mammalia
Primate
Hominidae
Homo
Homo sapien
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