Transcript Chapter 2: Intro to Multicellular Organisms


In single-celled, one cell performs ALL
functions.

In multi-cellular, different cells perform
different functions.
› They are specialized to do specific jobs.

Almost all multi-cellular organisms belong
to the plant, fungi, and animal kingdoms.
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Begins with the cell.
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Cells that perform the same job join
together to form tissue.

The tissues join together to make an
organ, and organs that work together
form an organ system.
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Different organ systems have specific
purposes in an organism.
› Nervous: respond to environment
› Muscular: movement and heat
› Respiratory: inhale O2 and exhale CO2
› Circulatory: delivers O2 in blood and remove
CO2 in blood
› Digestive: breaks down food

An adaptation is any inherited
characteristic that increases the change
of an organism’s survival and
reproduction.
› Getting energy
› Shape/structure of body
› Behavior

When an organism reproduces an
offspring with a unique trait, it is
considered an adaptation if it is
helpful/advantageous.

Fennec fox: desert fox; large ears keep it
cool and fur color helps it blend.
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Arctic fox: cold north; small ears, legs,
and nose reduce heat loss; winter coat is
thicker and white.
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Red fox: grasslands/woodlands; body fur
helps it blend with its surroundings.
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Adaptations result in diversity through
sexual reproduction.
› The DNA in the offspring is not the same as
the DNA in the parent.

Meiosis produces gametes (1n/haploid)
cells, containing only one copy of DNA.
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When male and female gametes are
joined, fertilization occurs and the DNA
from both parents are combined to form
the new offspring.
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Most multicellular organisms reproduce
by sexual reproduction; some can
reproduce asexually (one parent).
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Budding– second organism grows off
parent; identical DNA.
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Chemical energy is the form of energy
that all organisms use to carry out life
functions.
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Plants capture light energy and convert
it into chemical energy through ---

Plants take in water + CO2 + sun energy

Turn it into glucose (sugar) and oxygen
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Mostly take place in the leaves, which
are green because of…?
› Chloroplasts
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Plants are also called autotrophs, which
means “self-feeder”.

Algae and some bacteria/protists are
also able to use photosynthesis.
› Plants are a different type of producer
because they have specialized cells to story
energy  excess energy is stored as starch.

When plants need to release energy, the
starch is broken down and cellular
respiration occurs.

Leaves, stems, and roots allow plants to
live on land.

Grass: deep roots, produce seeds
quickly, and can grow in various areas.

Trees: cannot survive in harsh conditions,
but different types of trees can survive in
different areas.
› Coniferous: (pine) do better is cold climates;
needle-shaped leaves stay green.
› Deciduous: (maple) need long growing
season and loses leaves in cold temps.

Protection: some plants have
adaptations that prevent them from
being eaten.
› Mustard: odor
› Poison Ivy/Oak: harmful chemicals
› Nicotine: poison

Specific Needs:
› Venus Fly Trap: leaves fold to capture
insects; fluids given off by the leaves break
down the body, and nutrients are given off
to the plant.

Plants can respond to a stimulus:
something that produces a response
from an organism.
› Gravity, touch, and light
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Plants respond to gravity and have a
sense of up and down.
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Some plants have special stems called
tendrils.
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These plants grow in close contact with
another object to help raise it closer to
the sunlight.
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Stems and leaves grow toward light
because they have a special hormone:
chemical substance that is produced in
one part of the organism and creates a
reaction.
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Auxin
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Step 1: sunlight stimulates production of
auxins at the tip of the stem.
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Step 2: auxin moves to cells on dark side.
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Step 3: cells with auxin grow longer cells,
causing them to bend to light.
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Shorter daylight (fall/winter) means less
time to capture sunlight.
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Many plants go into dormancy, causing
them to temporarily stop growing.
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Trees and other plants can survive the
winter, and grow leaves back. Other
plants must be replanted every year.
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Seasons can also affect reproduction:
short day plants vs. long day plants.
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Animals are consumers: organisms that
need to get energy from another
organism.
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Heterotrophs: organisms that feed on
other organisms.
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Simple feeding: filtering food from
environment.
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Complex feeding: searching for food
and/or capturing food.
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Herbivores: plants/algae
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Carnivores: other animals
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Omnivores: plants and animals
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Digestion is the process that animals use
to break down food.
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Digestion uses physical and chemical
activity.
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Some animals, like sponges, can take in
food particles directly into their cells.
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Jellyfish have a single opening in their
bodies to take in food and expel wastes.
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Most animals have a tube-like systemmouth at one end, waste released at the
other end.
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Animals obtain energy through cellular
respiration.
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Most animals take in water through their
digestive system.
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The oxygen needed for cell. resp. is
brought into the body in different ways.
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Insects: spiracles – tiny openings in body
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Fish: gills – oxygen in water
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Others, like humans, take in oxygen
through the lungs.

For most animals, muscle and skeletal
systems provide movement and support.
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Nervous systems allow animals to sense
and respond to stimuli.
› Light, sounds, odors, temp, hunger, thirst, etc.
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Behavior: any observable response to a
stimulus.
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Some behaviors are inherited (spiders
spinning a web), and others are learned.
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Often meet basic needs – food, water,
shelter.
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Respond to environment
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Social behaviors
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Parents and offspring
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Behaviors for attracting mate
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Working together or being competitive
› Hunting in packs/competing for space
Competition: The search for food.
 Predator: animal that hunts other
animals.
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› Running fast, hunting abilities
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Prey: animal that is being hunted.
› Escaping predators, hiding, running in packs.
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Cooperation: tickbirds remove ticks from
the skin of an impala.
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This is symbiosis – it benefits both animals.
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Migration: the movement of animals to a
different region in response to
environment.
› Monarch butterflies, birds
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Hibernation: sleeplike state that lasts for
an extended time period.
› Frogs, turtles, fish, insects, etc.
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Break down the complex carbon
compounds that are part of living
matter.
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They are heterotrophs.
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Decompose bodies of plants/animals,
fallen leaves, shed skin, and animal
droppings.
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Most multicellular (except yeast)
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Nucleus and thick cell wall
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No specialization
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Has reproductive body and network of
cells called a hyphae.
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A mass of hyphae is called a mycelium.
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Hyphae – just one cell thick.
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Cells release chemicals to break down
materials around them.
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A spore is a single reproductive cell that
can grow into a new organism.
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A single mushroom can make a billion
spores, which are spread through the air
by wind.
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Hyphae can break and new mycelium
can form – like budding.
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Yeast can have a simple cell division or
budding.
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A single mushroom is a part of a much
larger mycelium.
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Some are edible, some are poisonous
(toadstool).
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The cap produces spores; the cap and
stalk are filled with hyphae.
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Mold that we commonly see is the sporeproducing part of fungus.
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Hyphae grow into the food.
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Used to make cheese (Penicillium) and
soy sauce (Aspergillus).
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Can cause disease (athlete’s foot).
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Can treat disease (Penicillin).
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Reproduce with spores, mostly through
the moving air.
› Pilobolus shoots a spore-containing cap up
to two meter away because of pressure.
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Single-celled
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Moist environments and surfaces
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Some grow on human skin, which can
cause disease.
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Makes bread rise
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The main decomposers on Earth.
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releasing nutrients of decaying materials
into the soil.
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This helps the plant that the hyphae is
surrounding.
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Single-celled algae
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Can live just about anywhere
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Many produce toxins – harmful
chemicals

The potato famine in Ireland.
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Some fungus is used for medicines –
penicillin.
› Prevents bacteria from reproducing
successfully.