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 –ending seed dormancy –rapid growth of young seedlings –rapid growth of some flower stalks Gibberellins are plant hormones that produce dramatic increases in size.

22.5 Plant Hormones and Responses –some fruits picked before they are ripe –sprayed with ethylene to ripen when reach destination Ethylene causes the ripening of fruits.

22.5 Plant Hormones and Responses –final stage in cell division –produced in growing roots, seeds, and fruits –involved in growth of side branches Cytokinins stimulate cytokinesis.

22.5 Plant Hormones and Responses Auxins lengthen plant cells in the growing tip. –stimulates growth of primary stem –controls some forms of tropism 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. PhototropismPhototropism 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 –climbing plants and vines –plants that grow in direction of constant wind Thigmotropism is a plant’s response to touchlike stimuli.

22.5 Plant Hormones and Responses –positive gravitropism is downward growth (roots) –negative gravitropism is upward growth (shoots) GravitropismGravitropism is a plant’s response to Earth’s gravitational pull.

22.5 Plant Hormones and Responses –Some responses protect plants from predators. –Some responses allow plants to capture food. Some plants have rapid responses not involving growth.

22.5 Plant Hormones and Responses –triggers some plants to flower –triggers fall colors/winter dormancy of deciduous trees PhotoperiodismPhotoperiodism is a response to the changing lengths of day and night.

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 –Kinesis is an increase in random movement. Taxis – 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. circadian rhythmA 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. hibernation –During hibernation, an animal enters a seasonal dormant state.

27.1 Adaptive Value of Behavior Behaviors may occur daily, monthly, seasonally, or annually. migration –During migration, animals move seasonally from one portion of their range to another. –During hibernation, an animal enters a seasonal dormant state.

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 cellnerve 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 –determination, or committing to become one cell type –differentiation –differentiation, or acquiring specialized structures and functions

28.1 Levels of Organization cell 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. tissue –epithelial tissue –connective tissue –muscle tissue –nervous 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? Name 3 body systems What is the function of each system Then list 2 organs in each body system Make a chart SystemFunctionOrgans How do the systems interact? Short Answer: Describe how 2 of the systems you listed are connected.

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. 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. CELLTISSUEORGAN vascular tissue leaf stem lateral roots primary root SYSTEMS root system shoot system

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. HomeostasisHomeostasis involves keeping the internal environment within set ranges.

28.2 Mechanisms of Homeostasis Control systems help maintain homeostasis. pore sweat glands hair follicle muscle goose bump Sensors gather data Control center gathers data and sends response Communication system delivers messages to target organs and tissues Targets respond to change

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, CO 2 levels rise, Control system forces exhale, inhale O 2 / CO 2 level returns to normal

28.2 Mechanisms of Homeostasis Positive feedback increases change. –Torn vessel stimulates release of clotting factors –growth hormones stimulate cell division platelets fibrin white blood cell red blood cell blood vessel clot

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 –Thermoregulation maintains a steady body temperature Skin absorbs UV light Liver produces inactive vitamin D Kidneys produce active vitamin D Active vitamin D used in bones UV light

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 cells attacked;insulin declines Blood glucose levels rise, Body burns fat; blood more acidic, Cells impaired; all organs damaged. pancreas fats kidneys