Orientation in Time

Question 1

What are biological rhythms

Answer 1

they are rhythmic activities that occur at regular time periods within animals
they are linked to many environmental factors

Question 2

describe what are circadian rhythms
i.e what kind of rhythm are they
what is the length of the rhythm
what environmental cycle are they linked to 
and what factor are they triggered by

Answer 2

a type of daily rhythms
length of 24 hours
linked to the day and night cycle
triggered by light availability

Question 3

what is an example of circadian rhythms

Answer 3

humans have circadian rhythms as we got to sleep at night and are awake during the day time.
other examples include nocturnal animals who stay awake during the night time and go to sleep during the day.

Question 4

describe what are circANNUAL rhythms
i.e what kind of rhythm are they
what is the length of the rhythm
what environmental cycle are they linked to 
and what factor are they triggered by

Answer 4

circannual are yearly rhythms
length of 365.25 days ( the amount of time it takes for the earth to orbit the sun)
linked to seasons
the seasons affect day length and so circannual rhythms are triggered by day length

Question 5

what is an example of circannual rhythms

Answer 5

animals that experience migration and hibernation at certain times of the year which is linked to the seasons
an example of this is when bears hibernate during the winter

Question 6

describe what are circTIDAL rhythms
i.e what kind of rhythm are they
what is the length of the rhythm
what environmental cycle are they linked to 
and what factor are they triggered by

Answer 6

circatidal rhythms are related to tides
length of 12 hours
linked to tidal changes (which are controlled by the gravitational pull of the moon on the earth)

Question 7

who has circatidal rhythms are how do tidal changes affect them

Answer 7

only animals living in tidal zones have circatidal rhythms are they will become active when the tide is high or in and inactive when the tide is low or out,
this is because when the tide is in the animals are submerged under water and this is the time for feeding and reproduction so they are active, where as when the tide is out, the organisms are exposed to air and threatened by drying out and therefore become inactive

Question 8

what causes the changes in tides

Answer 8

the gravitational pull of the moon on the earth
the pull creates the tides
but the rise and the fall of tides are caused by earths rotation relative to the moon

Question 9

describe what are circaLUNAR rhythms
i.e what kind of rhythm are they
what is the length of the rhythm
what environmental cycle are they linked to 
and what factor are they triggered by

Answer 9

they are monthly rhythms
length of 29.5 days
that are related to the orbit of the moon around the earth
they are linked and triggered by the moon cycle

Question 10

what is an example of circalunar rhythms

Answer 10

werewolves!!!! during a full moon werewolves turn from man to beast, this is a circalunar rhythm.

Question 11

what are long day plants

Answer 11

they only flower during the long day lengths, and therefore only flower during summer

Question 12

what are short day plants

Answer 12

they only flower during the short day lengths, and therefore only flower during winters

Question 13

what are day neutral plants

Answer 13

these plants are not affected by the day length and flower during any day length and therefore any time of the year

Question 14

what is phytochrome and how does it work

Answer 14

phytochrome is a type of plant pigment that comes in two forms, red and far red
phytochrome controls the photoperiodism repsonse, during the day there is lots of red light which is absorbed by the red pigment and converted to far red, then at night time the far red converts to red (and the cycle continues?)

Question 15

how does phytochrome affect long day and short day plants

Answer 15

long day plants require a lot of far red pigment to flower and so therefore requires longer day lengths so that more red can convert into far red
short day plants require a lot of red pigment to flower and therefore requires shorter day lengths so that less red can convert to far red and there is more red for the plant to use to flower.

Question 16

when do plants reproduce and why

Answer 16

plants try to flower at the same time each year so that their seeds will germinate at the same time and they do this when the chance of survival is the HIGHEST
for example if the flowers are pollinated by insects the flowering would need to occur when insects are most active.

Question 17

what are exogenous rhythms

Answer 17

exogenous rhythms are rhythms that are externally driven, this means they are controlled by something outside of the body

Question 18

what are controls and factors of exogenous rhythms

Answer 18

light availability
tide length
changing day length

Question 19

what are endogenous rhythms

Answer 19

endogenous rhythms are internally driven meaning they are controlled by something within the body, (an internal clock), the internal clock regulates the rhythms of activities

Question 20

what is the difference between endogenous rhythms and exogenous rhythms

Answer 20

endogenous rhythms are no affected by the environment and can continue even when the environment remains constant, where are exogenous rhythms are affected by the environment and when they it changes.

Question 21

what are zeitgebers

Answer 21

environmental cues that reset the internal clock (light availability, temperature, humidity)

Question 22

what is an example of zeitgebers

Answer 22

sunrise and sunset, a thing of the environment that tells our body when to wake up and start activity and when to go to bed and become inactive. this is controlled by light availability

Question 23

what is entrainment

Answer 23

the act of resetting internal clock to match the environment

Question 24

what is phase shifting

Answer 24

when an internal clock has been entrained, phase shifting occurs, it is when the time of activity or inactivity has been pushed backwards of forwards

Question 25

what is an actogramy

Answer 25

actograms are graphs that show hen an organism is active or inactive over the course of one day, as well as the changes in an environment

Question 26

what is an actogram

Answer 26

actograms are graphs that show hen an organism is active or inactive over the course of one day, as well as the changes in an environment

Question 27

what are actograms used for

Answer 27

they are used to find out when a rhythm is exogenous or endogenous, the length of the rhythm and any phase shifting occurring

Question 28

what is the purpose of photoperiodism

Answer 28

Photoperiodism is the regulation of seasonal activity by

day length.