Class Notes

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07.25.18 - Factors Impacting Migration

Abiotic Factors:

Salinity

Intertidal zone organisms can experience large, rapid changes in the salinity of their environment due to changes in the weather and climate

Water evaporates, salt concentration decrease and water increase - massive automosic effect on the organism (osmosis can affect the impact of movement on an organism)

Desiccation

Temperature

Leads to migrational pathways during certain seasons

Climate changes are not ideal to enable successful reproduction to occur

The success of breeding in the change of temperature right for the animal/plant

The way they behave is impacted by temperature - in winter it is quite possible for intertidal organisms to experience low tides with air temperatures colder than usual

Harsh temperatures aren't ideal - not optimum conditions for egg-laying, so migration is needed to find optimum condition for such

Gradient

Light

Oxygen

Dissolved oxygen concentration

In the sea, oxygen dissolved results from photosynthesis of marine producers - diffuse between the air and the sea at the water surface

Oxygen content is less than the air

Aspect

Wave Crash

Nutrient Availability

Important nutrients for algal growth like iron, magnesium, nitrate and phosphate are dissolved in seawater

Interspecific Competition

Predation

Food Availability

Innate Behaviour:

Heritable

Passed on through genetics

Intrinsic

In isolation, can carry out certain behaviours

Stereotype

All behaviours are the same, not diversify - all members of the species have the same behaviour

Inflexible

Not going to change regardless

Consummate

From birth, they can carry out the behaviour

Learned Behaviour:

Non-Inheritable

Not intrinsic

Permutable

Adaptable

Progressive

Examples: habituation, imprinting,

Differences Between The Two:

Innate - inherited, passes from one generation to the next, develops at a slow pace via natural selection, traits are developmentally fixed

Learned - spread through the population, passed within a single generation

Taxes:

Single-celled algae - accumulate where there is the greatest light-intensity

Earthworms - negative taxes response to light, desiccate and dry out if they don't move away from stimulus

Bacteria -

Woodlice - permeable,

Maggots - negative taxes, associate light with desiccation

Silkmoth -

Phagocytes -

Kineses:

More unfavourable the conditions - more rapidly the organism moves and changes directions more often

Response enables the organism to return to favourable conditions more rapidly

Difference Between Orthokinesis and Klinokinesis:

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07.27.18 - Homing (Navigation Methods)

Magnetism

Magnetic fields to coordinate the direction of birds

Topographical memory

Celestial

Smell

Disadvantages: of migration?

Predation

The energy required to migrate vast distances made reduce energy to successfully breed/reproduce - energy expenditure

Advantages: of migration?

Ideal conditions for survival and reproduction

Reducing the risk of predation/competition

Seek energy from a plentiful food supply

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07.30.17 - Circadian rhythms and Actograms

Nocturnal: animals active during the night

Diurnal: animals active during the day

Crepuscular: animals active during dawn and dusk

Annual Rhythms:

Effects of the Earth orbiting the Sun and the angle of the Earth's axis (23.45 degrees Celsius)

Affects both plants and animals

Photoperiods -

Migration/hibernation/leaf fall affected

Tidal Rhythms:

The position of the moon affecting the tidal rhythms

Two high tides and two low tides as a result of the common centre of gravity - water pile up

Risk of predation and desiccation if tidal rhythms cease

Zeitgebers:

external factors which entrain our biological rhythms

Melatonin binds to receptors in brains - causes metabolism in the body to slow down, leading to the sleepy state

Coffee inhibits melatonin from being activated in the brain

Biological clock -

The main zeitgeber is the relative light from the sun

Biological clocks are different for everyone due to the zeitgeber

Circadian Rhythms:

Endogenous rhythms with a free-running period of approx. 25 hours that is entrained by zeitgeber (diurnal, nocturnal, crepuscular)

Periods range between 23.5 and 24.5 hours in humans

Regulates sleeping and feeding patterns, alertness, core body temperature, brain wave activity, hormone production, regulation of glucose and insulin levels, urine production, cell regulation

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08.2.18 - Actograms

Bars same, the period of activity was constant- using zeitgebers to remain active at the same time of the day, endogenous rhythm being entrained by zeitgebers

Bars different - not using zeitgebers and relied on the biological clock

Free-running period - no zeitgebers and relying on the endogenous clock inherited from parents

Showing us the impact the biological clock has by taking away any zeitgebers

Can calculate the endogenous rhythm from the actogram

Free-running will be more or less than 24 hours

Shifted to the left or right by however much by using a rule to rule through the start line from the first day to the seventh and then a line of the angle, calculating the difference in the shift

Calculate the start of Day 1 and finish of Day 7 in hours

zeitgeber is the intensity of light

circadian rhythm synchronised with the environment as a result of zeitgebers

1. Not exposed to zeitgebers - it is a free-running period

i. if going to the right, their natural endogenous rhythm (independent of any zeitgebers), its biological clock is longer than 24 hours

ii. if sliding to the left, the endogenous rhythm would be shorter than a 24 hour period

2013 NCEA Question:

Only active during the dark period - consistent in actogram

Light exposure is the zeitgeber which is being exposed to the squirrel - constantly exposed over the duration of 23 days, entrain their biological rhythm with the use of these zeitgebers

Without the zeitgeber - still a period of activity is roughly the same length as the daily basis, simply relies on its endogenous biological clock (inherited) to enable it to carry some period of activity without external cues or factors (zeitgebers)

Yet their activity changes on a daily basis - shifts to the right

Biological clock longer than 24 hours

Calculating endogenous rhythm:

Draw line at the initial period of activity (takes you to day 19)

Draw line at last period of activity (day 26)

Difference between those - 7-day difference

Over 23 days the period activity has changed by 8 hours (roughly)

Division - 8/23 = 0.34

0.34h in minutes is roughly 20

Natural endogenous rhythm is 24 hours and 20 minutes without any external cues - that's why actogram moving to the right (no synchronisation of circadian rhythm due to zeitgebers)

Adaptive Advantages: benefit of training biological rhythm in relation to reproductive success, avoiding predators, overcome competition

Fewer competitors for food sources

Fewer predators during this time of day (in being nocturnal)

Increases reproductive success and survival

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08.7.18 - Plants

Have no central nervous systems

No rapid movements

Still able to respond to the environment

Respond to light

Growth movement - tropisms; slow growth, permanent changes in the cell

Turgor movements - nastic responses; rapid response, reversible, osmotic effect

Affected by temperature on enzyme activity

Other aspects of growth:

Abscission - detachment of leaves (linked to dormancy)

Dormancy - suspended growths, energy requirements decrease considerably

Vernalisation - chilling treatment

Meristem cells

Ability to differentiate into different parts of a plant

Xylem vessels

Root anatomy

Cell differentiation - meristem cells, undifferentiated, cell specialisation (phloem/xylem/root hairs)

Cell elongation - increasing water content, large vacuole, stretching

Primary plant growth - lots of cell division occurring, mitosis

Cell undergoing replication on the tip of root - older cells pushed back into the mature region of the root hair, small cells begin to elongate and causes the cell wall of the cells to become less rigid, easier for the cells to elongate through osmosis (water can enter the cell better, vacuole gets longer), cell differentiate occurs when the mature cells have been pushed back too far, are mature enough, will form a root hair cell or a xylem

Auxins - hormone inside the plant that promotes stem elongation, adventitious root initiation, and fruit growth; inhibit axillary bud outgrowth and leaf abscission

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08.9.18 - Auxin and Phototropism

Auxins:

Consider the following:

How do auxins move across to the shaded part of the plant (transport method)?

What impact does auxin have on the rigidity of the cell wall?

What causes the cell to swell and elongate?

Have an impact on the rigidity on the cellulose cell war

Causes hydrogen bonds to break, allowing the rigidity to break and elongate

Auxin answer: 2013 NCEA Question

Auxins move into the cells which are shaded by active transport

Has a direct impact on the rigidity of the cell wall

Greate the concentration, the less rigid the wall

Happens due to the break down of hydrogen bonds that increase the rigidity of the cell wall

Shaded cells have more auxin and less rigid cell walls

Stretching and elongating of the cell becomes easier for water to move into the cell by osmosis

With a lower concentration of auxin (light exposed sides) have more rigid cell walls

Not elongate as much (restrictive cell walls

Cells on the shaded side of the plant will grow longer

Plant bends towards the light

Auxin and (positive) Geotropism answer: 2013 NCEA Question

IIA (auxin concentration) controls the response to gravity

Cells able to detect the stimulus - starch grains (statoliths) within the root cap move to the lowest part of each cell

Effect of this movement influences the transport of IIA

Elongation occurs on upper cells

Auxins accumulate on the side the starch grains settle

Auxin inhibits the elongation of these cells

Upper cells which have few auxin hormones present - elongate

Root bends towards the ground - changes its orientation

Auxin efflux from right

Light on the right-hand side

Cells move to the shaded side

Elongate and cell wall less rigid

Stem bends towards the light

Equal auxin distribution

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08.14.18 - Question 3 2013

When explaining the role of gravity, light, and auxin in the growth of a shoot from germination into a mature plant:

Explain that Below Soil Surface:

1. Auxin produced at the shoot tip/apical meristem

2. Settles on the lower side of the cells

3. This causes cell elongation

4. Cells on the upper side continue to grow normally

5. Shoot grows upwards

6. Negative gravitropism

Explain that Above Soil Surface:

1. Auxin produced at the shoot tip/apical meristem

2. Settles on the shaded cells

3. This causes cell elongation

4. Cells on the non-shaded side continue to grow normally

5. Shoot bends towards light

6. Positive phototropism

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08.21.18 - Speciation

Co-evolution: 2 different species are ecologically intimate and influence each other's evolution

Interspecific competition

A relationship which is between members of different species

Three forms of it -

Commensalism

Mutualism

Exploitation - herbivory/parasitism/predation

Explotion - plant defense mechanisms

Secrete Cyogenic Glcosides to prevent tissue damage at the leaf through secreting hydrogen cynaide to kill any predators from consuming the leaves

Trichromes, tiny hears that are very sharp, portured the skin and screte poison

Disruptive colourisation from zebras - illusion effect on predator

Mimcry

Patterns in Evolution:

Divergence

The common ancestral population will diverge into separate species due to different selection pressures

Adaptive Radiation

The common ancestral population have more ecological niches made available to them (niche differentiation) - this often happens as a result of ecological activity

Different niches are exposed to different selection pressures - select specific alleles within each population

Gene pools will become more varied/variable and allele frequencies will change - become new species

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09.19.18 - K and R strategist

Aggression and Territorial behaviour in the same species

Competition:

Nutrients (food, water)

Mates

Breeding sites

Roosting sites

Causes a decrease in natality (birth rate) - only winners get to breed, which is a good thing for the species, as only the strongest pass on their genes to the next generation

Agonistic Behaviour

Social behaviour related to fighting or conflict situation among members of the same species

Aggressive or submissive behaviour

Aggressive - fighting, territoriality, hierarchal behaviour

Aggression

Protect young

Fight for access to mates

Fight for some crucial resources in limited supply (space, food)

Self defence and property protection

Pain

Motivational conflict (animal is trapped)

Fighting

To the death does not occur very often (submissive behaviour)

Winner ends up with the greater share of the resource - top of heirachial chain, result in mating and passing successful alleles, greater reproductive success, greater allele freuqnecies within the gene pools of the population selected for in the enivronment

More scarce the resource, the more intense the fighting

Territory

Area that an individual or a group actively defneds

Defends against those who occupy the same niche (want the same resources)

Usually against members of the same species??

Home Range

Area animao roams about/lives in in seasnally or throughout year

Not defended

May overlap with other animls' home range

Compact

No fixed boundaries

Advantages of maintaining a Terriotiry:

Only the fittest animals can hold a territory so only the best geens get passon onto offspring

Ensures enoguhg ood and water for animals that hold a territory

Reduce predation as holders are familiar with their territory and can avoid peedators more successfully

Reduces aggression when territory established - esnures a saf,e protected nest or home for young

Reduces spread of disaease and parasites

Ensures enough space for each animal - if in short supply and is needed for breeding, will keep the population down

Disadvantages

Energy cost - uses up energy defending the territory

Energy cost - group does not have as much time to find food for themselves as they are too busy defending territory