Altruism, Kin Selection, and Social Insects in Sustainability
Sustainability &
Interdependance
Key Area 6b & c
Altruism, Kin Selection & Social
Insects
Learning Intentions
By the end of this topic you should be able to:
Altruism
Altruism
Altruistic behaviour is
unselfish
behaviour which is harmful to
the donor and beneficial to the
recipient.
e.g. one meerkat standing guard
while others eat
There are two possible
explanations for altruistic
behaviour:
1)
Reciprocal altruism
2)
Kin selection
Reciprocal Altruism
Reciprocal altruism
This involves one animal giving help to
another animal in the prospect of the
favour being returned.
e.g. grooming to remove parasites in
apes.
There is an assumption that the favour
is returned at a later date and it
requires
intelligence
in animals to
remember who is indebted & how to
recognise cheats.
Reciprocal Altruism - Bats
Bats can only go without food for 2
nights but successful vampire bats
regurgitate blood
to help out
unsuccessful hungry bats.
Hungry bats then
lick the faces
of
successful bats
Successful bats will only do this for
bats that have helped them out in the
past
Altruism
Kin Selection
Kin Selection
Behaviour that appears to be
altruistic between a donor and a
recipient if they are
related
(kin)
For example, when a
parent/sibling/child sacrifices
itself for the survival of a closely
related recipient (child, sibling,
parent) in the knowledge that
their genes will be passed on
Advantage of Kin Selection?
The donor benefits
indirectly as their
shared genes
live on by
allowing the
recipent
(offspring) to
reproduce
In a way, this ensures
the donor’s
immortality.
Coefficients of relatedness
Coefficients of
relatedness table
shows the
proportion of genes
that are identical in
related individuals.
Coefficients of relatedness
A sister gives up her life for three of her
siblings (r = 0.5):
benefit =
0.5
×
3 = 1.5
cost =
1.0
(benefit – cost) =
1.5 – 1.0 = 0.5
Thus the sacrifice is a benefit that
outweighs costs and the gene for altruism
could evolve in a population.
Social Behaviour in Insects
Social Insects
Complex patterns of social behaviour
have involved in societies of insects
such as
A)
Bees (& wasps)
B)
Ants
C)
Termites
Bees (& wasps)
Social insects - division of labour
Close co-operation
occurs between the individuals
caring for the young.
1.
Food gathering and defence
2. Reproduction is the
by many sterile members
responsibility of a few
fertile members
Honey Bees
Three castes exists
1.
Queen
(1 female per colony)
2.
Workers
(many thousand females)
3.
Drones
(males – few hundred)
The queen produces eggs that are fertilised by
drones. The fertilized eggs become workers
Worker Bees (Kin Selection)
All sister worker bees share the same mother
(queen) and so have many genes in common.
Worker bees
maintain & defend the hive
rather
than reproducing themselves to ensure increased
survival of shared genes (kin selection)
Their duties include:
•
Storing pollen
•
Guarding hive from enemies
•
Foraging for food
Signalling in Bees
When bees forage for nectar
they
r
eturn to the hive to perform a
waggle dance
This c
ommunicates to the colony:
–
Distance, direction and richness
of food
This then m
inimises energy
expenditure of other members of
the hive in locating the food
The direction of the straight
run determines the direction of
the food source
The rate of looping indicates the
distance to the food supply.
The duration of the buzzing
indicates the quality of the
food source
Ants
Ants
Ants search for food in a
meandering pattern
Once the food is located the ant
returns to the colony leaving scent
markers behind it
Other ants follow the trail,
reinforcing the scent marks until
the supply is finished (old trails
fade away when not reinforced)
Termites
Termites have a major
contribution to
fertility of soil in semi-
desert and savannah
areas due to their role
in decomposition.
They decompose dead
wood and plant debris
and this releases
nutrients back into the
cycle
Altruism, kin selection, and social insects play crucial roles in sustainability. Altruistic behavior, like reciprocal altruism and kin selection, benefits recipients while potentially harming donors. Social insects, such as bees and ants, exemplify cooperation and societal structures that aid in ecosystem services like pollination and pest control. Explore how these concepts intertwine to support interconnectedness and sustainability.
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Presentation Transcript
Sustainability & Interdependance Key Area 6b & c Altruism, Kin Selection & Social Insects
Learning Intentions By the end of this topic you should be able to: Describe how altruistic behaviour can harm the donor individual but benefit the recipient. Describe how altruistic behaviour can be common between a donor and a recipient if they are related (kin). State that in kin selection, the donor benefits in terms of the increased chances of survival of shared genes in the recipient s offspring or future offspring. Define what is meant by social insects. Outline the structure of their society and their ecological importance evolution of the societies of insects such as bees, wasps, ants and termites, in which some individuals contribute reproductively. State that most members of the colony are workers who cooperate with close relatives to raise relatives. Describe how some species of social insects show ecological importance to humans in providing ecosystem services such as pollination and pest control.
Altruism Altruistic behaviour is unselfish behaviour which is harmful to the donor and beneficial to the recipient. e.g. one meerkat standing guard while others eat There are two possible explanations for altruistic behaviour: 1) Reciprocal altruism 2) Kin selection
Reciprocal altruism This involves one animal giving help to another animal in the prospect of the favour being returned. e.g. grooming to remove parasites in apes. There is an assumption that the favour is returned at a later date and it requires intelligence in animals to remember who is indebted & how to recognise cheats.
Reciprocal Altruism - Bats Bats can only go without food for 2 nights but successful vampire bats regurgitate blood to help out unsuccessful hungry bats. Hungry bats then lick the faces of successful bats Successful bats will only do this for bats that have helped them out in the past
Altruism Kin Selection
Kin Selection Behaviour that appears to be altruistic between a donor and a recipient if they are related (kin) For example, when a parent/sibling/child sacrifices itself for the survival of a closely related recipient (child, sibling, parent) in the knowledge that their genes will be passed on
Advantage of Kin Selection? The donor benefits indirectly as their shared genes live on by allowing the recipent (offspring) to reproduce In a way, this ensures the donor s immortality.
Coefficients of relatedness Relationship Parent offspring Siblings Half-siblings Uncle/aunt niece/nephew Grandparent grandchild Cousins Coefficient (r) 0.5 0.5 0.25 0.25 Coefficients of relatedness table shows the proportion of genes that are identical in related individuals. 0.25 0.125
Coefficients of relatedness A sister gives up her life for three of her siblings (r = 0.5): benefit = 0.5 3 = 1.5 cost = 1.0 (benefit cost) = 1.5 1.0 = 0.5 Thus the sacrifice is a benefit that outweighs costs and the gene for altruism could evolve in a population.
Social Insects Complex patterns of social behaviour have involved in societies of insects such as A)Bees (& wasps) B) Ants C) Termites
Social insects - division of labour Close co-operation occurs between the individuals caring for the young. 1. by many sterile members Food gathering and defence 2. Reproduction is the responsibility of a few fertile members
Honey Bees Three castes exists 1. Queen 2. Workers 3. Drones (1 female per colony) (many thousand females) (males few hundred) The queen produces eggs that are fertilised by drones. The fertilized eggs become workers
Worker Bees (Kin Selection) All sister worker bees share the same mother (queen) and so have many genes in common. Worker bees maintain & defend the hive rather than reproducing themselves to ensure increased survival of shared genes (kin selection) Their duties include: Storing pollen Guarding hive from enemies Foraging for food
Signalling in Bees When bees forage for nectar they return to the hive to perform a waggle dance This communicates to the colony: Distance, direction and richness of food This then minimises energy expenditure of other members of the hive in locating the food
The direction of the straight run determines the direction of the food source The rate of looping indicates the distance to the food supply. The duration of the buzzing indicates the quality of the food source
Ants Ants search for food in a meandering pattern Once the food is located the ant returns to the colony leaving scent markers behind it Other ants follow the trail, reinforcing the scent marks until the supply is finished (old trails fade away when not reinforced)
Termites Termites have a major contribution to fertility of soil in semi- desert and savannah areas due to their role in decomposition. They decompose dead wood and plant debris and this releases nutrients back into the cycle
