Sex & Behaviour Flashcards

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1
Q

Parental investment is costly but…

A

increases the probability of production and survival of young and therefore the evolutionary fitness of the parent

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2
Q

Description of female gametes (eggs)

A

Large, nutrient filled, expensive to produce, limited number and produced infrequently

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3
Q

Description of male gametes (sperm)

A

Small, no nutrients, cheap to produce, constantly made throughout life

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4
Q

What is the clearest sexual dimorphism amongst vertebrates?

A

Gamete size, this physical sex difference explains behavioural differences

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5
Q

How is there a greater investment by females?

A

In individual egg structures and also in the uterus during gestation in mammals

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6
Q

What is external fertilisation?

A

When the gametes are releases directly into the environmente.g. fish, crabs

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7
Q

Benefits of external fertilisation

A

Very large numbers of offspring can be produced

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8
Q

Costs of external fertilisation

A

Many gametes predated on or not fertilised
No/limited parental care
Few offspring survive to reproductive age

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9
Q

What is internal fertilisation?

A

When the gametes are releases into the reproductive tract of the female
e.g. humans, chimpanzees

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10
Q

Benefits of internal fertilisation

A

Increased chance of successful fertilisation
Fewer eggs needed
Offspring can be retained internally for protection and/or development
Higher offspring survival rate

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11
Q

Costs of internal fertilisation

A

Mate must be located which requires expenditure of energy
Requires direct transfer of gametes from one partner to another

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12
Q

R-selected and K-selected is a classification of organisms based on…

A

the level of parental investment and number of offspring produced

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13
Q

R-strategists use…

A

External fertilisation e.g. fish, crabs, insects

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14
Q

K-strategists use…

A

Internal fertilisation e.g. humans, chimps, elephants

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15
Q

Characteristics of R-selected organisms

A

Smaller and shorter generation time
Mature more rapidly
Reproduce earlier in lifetime (often only once)
Produce large number of smaller offspring
Offspring receive small energy input as there is limited parental care
Most offspring will not reach adulthood therefore do not reproduce

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16
Q

Characteristics of K-selected organisms

A

Larger and live longer
Mature more slowly
Reproduce many times in lifetime
Produce relatively few larger offspring
High level of parental care
Many offspring have a high probability of surviving to adulthood and therefore reproducing

17
Q

R-selected tend to occur in…

A

Unstable environments where the species has not reached its reproductive capacity

18
Q

K-selected tend to occur in…

A

Stable environments

19
Q

What are mating systems based on?

A

How many mates an individual has during one breeding season

20
Q

What is monogamy?

A

The mating of a pair of animals to the exclusion of all others e.g. humans, albatross

21
Q

What is polygamy?

A

When individuals of one sex have more than one mate

22
Q

What are the two types of polygamy?

A

Polygyny- one male mates exclusively with a group of females e.g. stag, elephant seal
Polyandry- one female mates with a number of males during the same breeding season

23
Q

Courtship involves…

A

Behaviours and characteristics associated with mate selection

24
Q

Successful courtship behaviour in… can be a result of…

A

Birds and fish, species-specific sign-stimuli and fixed action pattern responses

25
Q

What are fixed action pattern responses?

A

Instinctive and vary little between member of the same species

26
Q

What is shown by many birds and fish?

A

Ritualised courtship behaviours

27
Q

Sexual selection selects for…

A

Characteristic that have little survival benefit but increase chances of mating

28
Q

Many species exhibit… as a product of sexual selection

A

Sexual dimorphism (reversed occurs in some species)

29
Q

Males usually have more conspicuous…

A

Markings, structures and behaviours than females

30
Q

What is female choice?

A

When females assess honest signals for fitness of males

31
Q

Honest signals indicate…

A

Favourable alleles that increase chances of offspring survival (fitness) or low parasite burden (healthy individual)

32
Q

In lekking species…

A

Males gather at a lek where female choice occurs
e.g. bird species where dominant males occupy the centre of the lek with subordinates and juveniles at the fringes as ‘satellite’ males

33
Q

What happens during male-male rivalry?

A

Males fight for dominance and access to females using elaborate weapons (antlers, tusks, horns)

34
Q

Success in male-male rivalry…

A

increases access to females for mating