Chapter 2 Sex and Evolution Flashcards

1
Q

Evolution

A

The change in the genetic makeup of living populations over time.

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2
Q

Heritable

A

Capable of being passed down from parent to offspring

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3
Q

Gene

A

a stretch of DNA that is ttranscribed as a functional unit; a unit of inheritance.

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4
Q

DNA

(Deoxyribonucleic Acid)

A

the linear molecule that forms the chemical basis of genes in all species except some viruses.

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5
Q

Chromosome

A

a rod-shaped nuclear organelle composed of DNA and associated proteins

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6
Q

Genome

A

An organism’s entire complement of DNA, including all its genes.

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7
Q

Conjugation

A

Contact between two bacteria accompanied by the transfer of a short stretch of DNA (plasmid) from one another.

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8
Q

(1) Gamate
(2) Haploid
(3) Diploid

A

(1) a specialized call that fuses w another to form a new organism (sperm or ovum)
(2) Possessing healf the usual complement of chromosomes
(3) Possessing the full complement of chromosomes. All cells but gamates

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9
Q

Meiosis

A

A pair of cell divisions that produces gametes; involves exchange of genetic material between homologous chromosomes & reduction of chromosome # from diploid to haploid.

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10
Q

Explanations for Sexual Reproduction

A

The main idea is that it limits harmful mutations.

When organisms reproduce sexually harmful mutations can be eliminated. That’s because the offspring receives a randomly selected half of their mother’s genes and half of their father’s genes.

Also, sexual reproduciton might generate beneficial gene combinations.

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11
Q

Red Queen Hypothesis

A

The idea that sexual reproduction is advantageous because it helps defend organisms againts parasites

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12
Q

Why 2 sexes?

Hermaphrodite

A

Investment: the commitment or expenditure of resoruces for a goal, such as reproductive success.

An organism that combines male and female reproductive functions.

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13
Q

SRY

(Sex-determining Region of the Y chromosome)

A

a gene located on the Y chromosome that causes embryo to develop as a male.

Also, there is a connection between sexes and temperature. In some animals low temperatures will develop males and high will develop females. This is not constant among all species.

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14
Q

gestation

A

Bearing a young in the uterus; pregnancy

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15
Q

Reproductive Strategies: Risk

A

Males

Max # of potential offspring high
May not be able to find willing mate
Risk: inability to create offspring
Seek to mate WIDELY

Females

Max # of potential offspring low
Plenty of males willing to mate w/ her
Risk: failure of offspring to survive
Therefore, seek to mate WISELY

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16
Q

Pheromone

A

A volatile compound that is released by one organism and that triggers a specific behavior in another member of the same species.

17
Q

Females tend to pay attention to

A

Bodily symmetry.

Fluctuating Asymmetry; a difference between the left and right sides of the body that results from random perturbations of development.

18
Q

Proceptive Behavior

A

Behavior of females that may elicit sexual advances by males (courtship behaviors).

19
Q

Estrus

A

The restricted period within the ovarian cycle when females of some species are sexually receptive; “heat”

20
Q

What would happen if the sexes invest the same?

A

if males and females invest the same, sexual selection may not lead to any marked anatomical or behavioral differences between the sexes.

Remember the seagulls example

21
Q

Monogamy

Polygamy

Polygyny

Polyandry

A

Monogamy—2 animals form a Pair Bond
Polygamy—one animal forms a relationship w/ many members of the opposite sex:
Polygyny—many wives
Polyandry—many husbands

22
Q

Mate Guarding

A

mate remains close to female during the time in which she is fertile to keep other males away from her
Paternity (DNA) testing.

Sperim competition: By sheer force of numbers, sperm compete with the sperm of other males in the females’ reproductive tracts.