Download Chapter 22 and 27 and 28

22.5 Plant Hormones and Responses
KEY CONCEPT
Plant hormones guide plant growth and development.
22.5 Plant Hormones and Responses
Plant hormones regulate plant functions.
• Hormones are chemical messengers.
– produced in one part of an organism
– stimulates or suppresses activity in another part
22.5 Plant Hormones and Responses
• Gibberellins are plant hormones that produce dramatic
increases in size.
– ending seed dormancy
– rapid growth of young
seedlings
– rapid growth of some
flower stalks
22.5 Plant Hormones and Responses
• Ethylene causes the ripening of fruits.
– some fruits picked before
they are ripe
– sprayed with ethylene to
ripen when reach
destination
22.5 Plant Hormones and Responses
• Cytokinins stimulate cytokinesis.
– final stage in cell division
– produced in growing roots, seeds, and fruits
– involved in growth of side branches
22.5 Plant Hormones and Responses
• Auxins lengthen plant cells in the growing tip.
– stimulates growth of
primary stem
– controls some forms of
tropism
• A tropism is the movement
of plant in response to an
environmental stimulus.
22.5 Plant Hormones and Responses
Plants can respond to light, touch, gravity, and seasonal
changes.
• Phototropism is the
tendency of a plant to
grow toward light.
– auxins build up on
shaded side of stem
– cells on shaded
side lengthen
– causes stem to
bend toward light
22.5 Plant Hormones and Responses
• Thigmotropism is a plant’s response to touchlike stimuli.
– climbing plants and vines
– plants that grow in direction of constant wind
22.5 Plant Hormones and Responses
• Gravitropism is a plant’s response to Earth’s gravitational
pull.
– positive gravitropism is downward growth (roots)
– negative gravitropism is upward growth (shoots)
22.5 Plant Hormones and Responses
• Some plants have rapid responses not involving growth.
– Some responses protect
plants from predators.
– Some responses allow
plants to capture food.
22.5 Plant Hormones and Responses
• Photoperiodism is a response to the changing lengths of
day and night.
– triggers some plants to flower
– triggers fall colors/winter dormancy of deciduous trees
27.1 Adaptive Value of Behavior
KEY CONCEPT
Behavior lets organisms respond rapidly and
adaptively to their environment.
27.1 Adaptive Value of Behavior
Behavioral responses to stimuli may be adaptive.
• Detecting and responding to stimuli is key to an individual’s
survival.
• Internal stimuli tell an animal what is occurring in its own
body.
– hunger
– thirst
– pain
27.1 Adaptive Value of Behavior
• External stimuli give an animal information about its
surroundings.
– sound
– sight
– changes in day length or temperature
27.1 Adaptive Value of Behavior
• Specialized cells that are sensitive to stimuli detect sensory
information.
– information is transferred to the nervous system
– nervous system may activate other systems in response
• Animal behaviors help to maintain homeostasis.
27.1 Adaptive Value of Behavior
• Kinesis and taxis are two types of movement-related
behaviors.
– Kinesis is an increase in random movement.
– Taxis is movement in a particular direction.
27.1 Adaptive Value of Behavior
Internal and external stimuli usually interact to trigger
specific behaviors.
• Most behaviors are a response to both internal and external
stimuli.
• External stimuli may trigger internal stimuli
27.1 Adaptive Value of Behavior
Some behaviors occur in cycles.
• A circadian rhythm is the daily cycle of activity.
– occurs over 24-hour period
– run by a biological clock
27.1 Adaptive Value of Behavior
• Behaviors may occur daily, monthly, seasonally, or annually.
– During hibernation, an animal enters a seasonal
dormant state.
27.1 Adaptive Value of Behavior
• Behaviors may occur daily, monthly, seasonally, or annually.
– During hibernation, an animal enters a seasonal dormant
state.
– During migration, animals move seasonally from one
portion of their range to another.
27.2 Instinct and Learning
KEY CONCEPT
Both genes and environment affect an animal’s
behavior.
27.2 Instinct and Learning
Innate behaviors are triggered by specific internal and
external stimuli.
• An instinct is a complex inborn behavior.
• Instinctive behaviors share
several characteristics.
– innate, or performed
correctly the first time
– relatively inflexible
27.2 Instinct and Learning
Many behaviors have both innate and learned
components.
• Learning takes many forms.
• Habituation occurs
when an animal
learns to ignore a
repeated stimulus.
27.2 Instinct and Learning
• In imitation, animals learn by observing the behaviors of
others.
– young male songbirds
learn songs by listening
to adult males
– snow monkeys and
potato-washing
behavior
27.2 Instinct and Learning
Learning is adaptive.
• Animals that can learn can better adapt to new situations.
• In associative learning, a specific action is associated with
its consequences.
• Conditioning is one type of associative learning.
28.1 Levels of Organization
KEY CONCEPT
The human body has five levels of organization.
28.1 Levels of Organization
Specialized cells develop from a single zygote.
• Organisms are made up of specialized cells.
red blood cell
nerve cell
28.1 Levels of Organization
Specialized cells develop from a single zygote.
28.1 Levels of Organization
• Zygotes first divide into embryonic stem cells.
• Stem cells develop in
two stages.
– determination, or
committing to
become one cell type
– differentiation, or
acquiring specialized
structures and
functions
28.1 Levels of Organization
Specialized cells function together in tissues, organs,
organ systems, and the whole organism.
• Specialized cells perform specific tasks.
• Tissues are groups of similar cells working together.
– epithelial tissue
– connective tissue
– muscle tissue
– nervous tissue
cell
tissue
28.1 Levels of Organization
• Organs are different tissues working together.
• Organ systems are two or more organs working together.
• Organism is all organ systems working together.
ORGANS
ORGAN SYSTEM
ORGANISM
28.1 Levels of Organization
• There are 11 major organ systems in the human body.
28.1 Levels of Organization
How are body systems connected?
What are your body
systems?
Make a chart
System
Function
• Name 3 body systems
• What is the function of
each system
• Then list 2 organs in each
body system
How do the systems interact?
Short Answer: Describe how 2 of the systems you
listed are connected.
Organs
5.5 Multicellular Life
KEY CONCEPT
Cells work together to carry out complex
functions.
5.5 Multicellular Life
Multicellular organisms depend on interactions among
different cell types.
CELL
TISSUE
leaf
stem
vascular
tissue
ORGAN
lateral
roots
primary
root
root system
• Tissues are groups of cells that perform
a similar function.
• Organs are groups of tissues that
perform a specific or related function.
• Organ systems are groups of organs
that carry out similar functions.
shoot system
SYSTEMS
5.5 Multicellular Life
Specialized cells perform specific functions.
• Cells develop into their mature forms through the process
of cell differentiation.
• Cells differ because different combinations of genes are
expressed.
• A cell’s location in an embryo helps determine how it will
differentiate.
Outer: skin cells
Middle: bone cells
Inner: intestines
5.5 Multicellular Life
Stem cells are unique body cells.
• Stem cells have the ability to
– divide and renew themselves
– remain undifferentiated in form
– develop into a variety of specialized cell types
28.2 Mechanisms of Homeostasis
KEY CONCEPT
Homeostasis is the regulation and maintenance of the
internal environment.
28.2 Mechanisms of Homeostasis
Conditions within the body must remain within a narrow
range.
• Homeostasis involves keeping the internal environment
within set ranges.
28.2 Mechanisms of Homeostasis
• Control systems help maintain homeostasis.
pore
Sensors gather
data
sweat
glands
Control center
gathers data and
sends response
Targets respond to
change
Communication
system delivers
messages to target
organs and tissues
hair
follicle
muscle
goose
bump
28.2 Mechanisms of Homeostasis
Negative feedback loops are necessary for homeostasis.
• Feedback compares current conditions to set ranges.
• Negative feedback counteracts change.
Negative Feedback Loop
Holding breath, CO2
levels rise,
O2 / CO2 level returns to
normal
Control system forces
exhale, inhale
28.2 Mechanisms of Homeostasis
• Positive feedback increases change.
– Torn vessel stimulates release of clotting factors
platelets
blood vessel
fibrin
clot
white blood cell
red blood cell
– growth hormones stimulate cell division
28.3 Interactions Among Systems
KEY CONCEPT
Systems interact to maintain homeostasis.
28.3 Interactions Among Systems
Each organ system affects other organ systems.
• An organ system must do a specific job.
• Organ systems must also work together to keep the
organism healthy.
28.3 Interactions Among Systems
• Organ systems must also work together to keep the
organism healthy.
– Organ systems work together to produce Vitamin D.
– Thermoregulation maintains a steady body
temperature.
UV light
1
Skin absorbs UV light
2
Liver produces inactive vitamin D
3
Kidneys produce active vitamin D
4
Active vitamin D used in bones
28.3 Interactions Among Systems
A disruption of homeostasis can be harmful.
• Homeostasis can be disrupted for several reasons.
– sensors fail
– targets do not receive messages
– injury
– illness
28.3 Interactions Among Systems
• Short-term disruption usually causes little or no harm.
• Long-term disruptions can cause more damage.
• Diabetes is a serious long-term disruption of homeostasis.
pancreas
1
Pancreas cells attacked;insulin
declines
2
Blood glucose levels rise,
fats
kidneys
3
Body burns fat; blood more acidic,
4
Cells impaired; all organs
damaged.