Timing and Coordination Essential Knowledge 2.E.2 and 2.E.3 Timing - - PowerPoint PPT Presentation

Timing and Coordination

Essential Knowledge 2.E.2 and 2.E.3

Timing and Coordination

• Timing and coordination of physiological

events are regulated by multiple mechanisms (2.E.2)

• Timing and coordination of physiological

events are regulated by various mechanisms and are important in natural selection (2.E.3)

Essential Knowledge 2.E.2

Timing and coordination of physiological events are regulated by multiple mechanisms

Timing and coordination of physiological events are regulated by multiple mechanisms Examples of physiological events that involve timing and coordination:

• Plants – phototropism, photoperiodism
• Animals – hibernation
• Fungi – fruiting body formation
• Bacteria – quorum sensing

Plants

• In plants, physiological events involve

interactions between environmental stimuli and internal molecular signals

• Examples include phototropism and

photoperiodism

Phototropism

• Response to the presence of light – grow

towards or away from light

• Growth is triggered by auxin hormones

located within cells on the dark side of the shoot

Phototropism

Photoperiodism

• Response to change in length of the night,

that results in flowering in long-day and short- day plants

• Anticipate the seasons in order to flower at

the correct time of year

• Involves a pigment called phytochrome

(protein that acts as a photoreceptor)

Photoperiodism

Photoperiodism

Animals

• Internal and external signals regulate a variety
• f physiological responses that synchronize

with environmental cycles and cues

Circadian Rhythms

• The physiological cycle of about 24 hours that

is present in all eukaryotes and persists even in the absence of external cues

• Controlled by genetics and amounts of light

and darkness

• Jet lag is a common circadian rhythm

disruptor in humans

Circadian Rhythms

• Characterized by rising and falling hormone

levels, undulating body temperature, and the familiar sleep-wake cycle

• Pineal gland plays a role by secreting the

hormone melatonin

Hibernation

• A state of inactivity and metabolic depression

characterized by lower body temperature, slower breathing, and/or lower metabolic rate

• Conserves energy when food supplies are

limited

• Obligate hibernators, facultative hibernators,

torpor

Hibernation

• Obligate – driven by internal mechanisms,

“true hibernators”

• Facultative – can be aroused by external

stimuli

• Torpor – temporary hibernation

Fungi

• Internal and external signals regulate a

physiological response known as fruiting body formation that synchronizes with environmental cycles and cues

Fruiting Body Formation

• Spore-producing structure (often referred to

as a mushroom)

• Influenced by temperature, air humidity,

nutrients and light

Bacteria

• Use quorum sensing to coordinate behavior

and communicate based on population density

Quorum Sensing

(How Bacteria “Talk” – TED Talk – 18 minutes)

• A system of stimulus and

response correlated to population density

• Used to coordinate gene

expression and, through signal transduction, can influence the behavior of the entire community

Essential Knowledge 2.E.3

Timing and coordination of physiological events are regulated by various mechanisms and are important in natural selection

Timing and coordination of physiological events are regulated by various mechanisms and are important in natural selection Examples of mechanisms that are important in natural selection:

• Innate and learned behaviors
• Responding to information and

communication of information

• Cooperative behavior

Innate and Learned Behaviors

• Individuals can act on information and

communicate it to others

• Innate behaviors are behaviors that are

inherited (natural selection)

• Learned behaviors occur through interactions

with the environment and other organisms (natural selection

Innate Behaviors

Learned Behaviors

• Associative learning
• Habituation
• Cognition and problem solving

Response to Information and Communication

• Responses to information and communication
• f information are vital to natural selection
• Examples:

–Phototropism in plants, maximizes exposure

• f leaves for photosynthesis

–Photoperiodism in plants, regulate flowering and preparation for winter –Courtship behavior and migration in animals

Courtship Behavior

• Vital to reproduction, natural selection and

survival of the species

• Allows animals to distinguish between

different species to ensure compatible mates

Migration

• A regular long-distance change in location
• Observed in a wide variety of birds, fish and
• ther animals

Why do animals migrate?

• Found in all major animal groups – birds,

mammals, fish, reptiles, amphibians, insects and crustaceans

• In search of food or more favorable living

conditions when seasons change

• To breed (mate and produce offspring)

Monarch Migration

(Monarch Migration Video – 4 minutes)

Humpback Whale Migration

Cooperative Behavior

• Cooperative behavior within or between

populations contributes to the survival of the population Examples include:

• Niche and resource partitioning
• Mutualistic relationships

Niche and Resource Partitioning

• Allows species to coexist within communities
• Hunt for insects and nest in different areas of

the same tree

Mutualistic Relationships

• Both organisms benefit from the relationship