Chapter 10 –
Multicellular Organisms
10-1 – How they meet needs
10-2 – Plants are producers
10-3 – Animals are consumers
10-4 – Fungi are decomposers
Chapter 10-1 – Meeting needs
Multicellular organisms have cells that
are specialized.
In single-celled organisms, all
functions are performed by each cell.
Multicellular Organisms life functions
(getting energy/raw materials, waste
removal, responding to changes in
environ, reproducing) - done by
specialized cells.
10-1 Levels of Organization
Specialized organization starts with
the Cells (ex. Skin, nerve, muscle are
different)
Cells of same type = Tissue
Different tissues working together to
perform the same function = Organ
Organs have different functions
Organ systems have multiple organs
working together to perform the same
function & help the organism survive
10-1 MO’s have varied adaptations
Adaptation– any inherited
characteristic (shape, structure,
behavior, etc) that increases an
organism’s ability to survive &
reproduce offspring that reproduce.
10-1 Sexual Reproduction &
Diversity
Most MO’s reproduce sexually (2
parents needed; offspring’s DNA not
identical to parents)
Sexual Reproduction:
Meiosis = cell division that produces
male sperm and female egg cells which
contain one copy of DNA instead of 2.
Fertilization = sperm and egg cell unite
& new cell has 2 sets of DNA
male/female
10-1 Sexual Reproduction cont.
Some multi-celled organisms do not
reproduce sexually. Ex: “budding” in
plants
Differences in genetic material and in
the environment produce differences
in offspring.
How well something grows depends
on both genetics and environment.
10-2
Plants
Are
Producers
10-2 Plants Are Producers
Plants capture energy from the sun.
Energy from the sun cannot drive cell
processes directly.
Light energy must be changed into
chemical energy (Photosynthesis).
Chemical energy is the form of energy
that all organisms need to carry out
life.
10-2 Producing Sugars
Photosynthesis = process by which
sunlight energy is transformed into
chemical energy
Raw Materials: Water and CO2 are used
in the production of sugars
By-Products of Photosynthesis = O2
(oxygen) + sugar and/or starch
Most photosynthesis takes place in the
leaves; (autotroph=self feeder)
Roots, Stems, Leaves, etc.=organ sys.
10-2 Storing & Releasing Energy
Plants are MO’s and can store energy,
where simple 1-celled organisms cannot.
Plants store excess sugars as starches &
use them for growth.
Starches can store chemical energy
Cellular respiration is the process by
which a cell uses O2 to break down sugars
& release energy
10-2 – Plants are adapted
Plants are adapted to different
environments. (Different leaves,
stems, roots, etc)
Coniferous = cone bearing (ex.pine)
Deciduous = trees that lose leaves in
different seasons (oak, maple)
Other adaptations: how quickly they
flower & seed themselves
10-2 Respond to Environ.
Stimulus = something that produces
a response from an organism
Examples: gravity=roots grow down;
sunlight = leaves turn towards it;
flowers open/close
Touch = plant touches another object
and the plant’s tendrils wrap around
that object.
10-2 Respond to Environ.
Hormone = a chemical substance
produced in one part of organism that
travels to another part of the organism
where it produces a reaction or
response.
Auxin = a hormone that stimulates
cell growth in the tip of a plants stem
(or root). Auxins on the dark side of a
plant contain more auxins (which
avoid light) than cells on the lighted
side of a plant.
10-2 Seasonal Changes
Shorter period of sunlight (fall/winter)
affect photosynthesis time.
Seasonal changes trigger plant
“dormancy” when plants stop
growing to conserve energy
Plants also may change leaf colors &
drop leaves due to seasons.
Seasons also affect seed production
10-3
Animals
Are
Consumers
10-3 Food = Energy
Consumer = an organism that needs
to get energy from another organism.
Animals are heterotrophs
(organisms that feed on or consume
other organisms).
10-3 What Animals Eat
Herbivores = organisms that feed on
plants or algae.
Examples: Cows, ducks
Carnivores = feed on other animals
Example: Lions, wolves
Omnivores = feed on both plants and
animals.
Bears, Mice
10-3 Animal Interactions
Animal bodies have many adaptations
(systems) that allow it to process food
(digestive, respiratory, circulatory).
Other systems allow interaction
w/environment (muscular, skeletal,
nervous, etc.)
Behavior = an observable response
to a stimulus (light, sound, odor,
temperature.sight, etc)
10-3 Three Behavior Categories
Individual Behaviors
Ex: Often involve meeting basic needs (food,
water, shelter, sleep, grooming)
Animal to animal of same species or
“social behaviors”
Ex: Parent to offspring; attracting mates;
group hunting (wolves); bees in hive
Animal to animal of different species
Ex: Predator-Prey behaviors; or mutualism
(tickbirds removing ticks from impala)
https://www.youtube.com/watch?v=Ac
20YWRjvrQ
10-3 Animals Seasonal responses
Animals respond to seasonal changes
in their environment (drought, heat,
cold)
Migration – the movement of animals to
a different region in response to an
environmental change. (Ex: birds,
butterflies, wildebeast, elephants, etc.)
Hibernation – a sleeplike state that lasts
for an extended time period. (Ex. Frogs,
turtles, fish, bears, etc.)
10-4 Fungi
Fungi
Are
Decomposers
Fungi Absorb Materials
Most fungi are decomposers that
break down complex carbon
compounds and use them for energy
and raw materials.
They absorb nutrients and leave
behind simpler compounds
Fungi are heterotrophs
Characteristics of Fungi
All fungi are multi-cellular except Yeast =
unicellular fungi;
Organization: Cells have nucleus, thick
cell walls
Do not have: specialized tissues or
organs.
Do have: reproductive body & hyphae
(thread-like structures, one cell thick).
Mycelium = a mass of hyphae
Reproduction of Fungi
Fungi reproduce with spores which can be
produced either asexually or sexually.
A spore is a single reproductive cell that is
capable of growing a new organism.
Spores are air-borne, spread by wind, and
can survive many years.
Fungi can also reproduce asexually by
breaking off hyphae & regrowing a new
fungi; they can also “bud” (yeast)
What are Fungi? 3 types
Mushrooms – The outer part of a
mushroom is only part of the
fungus. The mushroom’s
hyphae/mycellum is underground
Molds – Spore producing part of
another type of fungus.
Yeasts = Single celled fungi; need
moisture, heat
Fungi: Helpful Or Harmful?
Helpful:
Penicillin is an antibiotic that helps treat
disease and make cheese (Brie,
Camembert, and blue cheeses). Penicillin
keeps bacteria from forming new cell walls
during reproduction so bacteria cells break
open and die.
Aspergillis fungus used to make soy sauce.
Trichoderma is used in making stonewashed jeans.
Lichen = fungi that live together with a
single-celled algae forming a sort of
“sandwich” around the algae.
10-4 Harmful Fungus
Many molds cause disease.
(Athlete’s foot; Dutch Elm Disease;
Powdery Mildew)
1845 Irish potato famine was caused
by a potato fungus which produced
toxins, disease & famine which killed
4 million people.