Use free energy to maintain homeostasis in response to environmental conditions In order to survive, organisms need: Timing and Coordination

Diversity of life on Earth 6 kingdoms Organisms detect environment conditions Organisms communicate Endocrine, Immune, Nervous System Animal behaviors

Maintaining homeostasis

Negative feedback: returning the changing condition back to its target set point Ex: temperature regulation in animals Ex: plant responses to water limitations Positive feedback: amplification of a response by moving away from its set point. Ex:ripening of fruit Ex: labor in childbirth

Leads to harmful effects on individual Ex: diabetes

Respond to a changing environment by using energy to maintain homeostasis

Organisms respond to changes in their environment through behavioral and physiological mechanisms

Excretory system in flatworms earthworms and vertebrates Osmoregulation in bacteria fish and protists Osmoregulation in aquatic and terrestrial plants Thermoregulation in aquatic and terrestrial animals

Using energy to respond to the environment to maintain homeostasis

Directed movement in response to stimulus toward attractant: food away deterent: poison Structure: flagellum

Bacteria expel proteins in normal lifecycle Populations increase other functions begin

When environment lacks specific nutrients, bacterial cell develops protective cell Genome is copied Water is removed Metabolism stops Original cell lysis Endospore endures Dormant for centuries

Using energy to respond to the environment to maintain homeostasis

Occur as a result of internal and external signals that synchronize with environmental cycles and cues Ex: fruiting body development in response to nutritional depletion

Using energy to respond to the environment to maintain homeostasis

Growth in response to light (positive) toward light shoots (negative) roots down Mechanism: auxin hormone

Response to timing of light Determine time of day/season Mechanism: phytochrome

Positive feedback mechanism Mechanism: Ethylene

Plants pass materials between cells

Physical defense: Thorns, trichomes Chemical defense: Glycosides Symbiotic defense: Recruitment of animals

Flower development

C4 plants

Using energy to respond to the environment to maintain homeostasis

Contact Plant Cells Short Distance Contact Animal Cells Long Distance

Hormones (Endocrine System) Antigens (Immune System) Neurotransmitters (Nervous System)

System-How-it-Functions System-How-it-Functions

Molecules produced by endocrine cells Typically travel through circulatory system

Medicine: Birth control Depression Blood pressure Metabolism

Defenses that activate immediately upon infection

Organism Barrier: Chitinous exoskeleton Cellular: Hemocytes ingest bacteria Molecular: Lysozyme enzymes break cell walls

Organism Barrier: Skin Cellular: Neutrophils and macrophages Molecular: Interferon & 30 protein complement system

Histamine and citokine signals trigger capillaries to dilate

Vertebrate defenses remembered after initial exposures

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Response of a muscle or gland under control of the nervous system in response to a stimulus Innate vs. Learned

Kinesis Random movement in response to stimulus Ex: Paramecium slow down and turn more often in the presence of bacteria (food)

Taxis Direct movement toward/away from stimulus Ex: American Cockroach hides from light

Detection of light to set internal clock Mechanism: pineal gland detecting sunlight

Regular long distance change in location Mechanism (in birds) Magnetite in brain to visualize magnetic field

Lowering of metabolism to survive seasons

Honeybees perform the waggle dance to communicate the location of food sources

Pheromones Ex: alarm or reproductive

Pack behavior in animals

A loss of responsiveness to stimuli that convey little or no new information Ex: prairie dog alarm call in human presence

Ability to associate one environmental feature with another Ex: Mouse associates color/taste

The process of recognizing and following the first moving object encountered during a “sensitive period” of life (learned/innate)

Scientists often wear costumes to prevent human imprinting with endangered species

The process of knowing by awareness, reasoning, recollection & judgment. Ex: primates learn how to use tools