Part 3 Topic D Flashcards Preview

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Flashcards in Part 3 Topic D Deck (32)
1

external fertilization

fertilization that takes place outside the body of the female; in aquatic organisms, for example, eggs and sperm are released into the water

2

internal fertilization

fertilization that takes place inside the body of the female

3

internal fertilization is an adaption for...

living on land, prevents gametes from drying out (some marine animals reproduce this way too)

4

external fertilization is generally associated with the release of....

large numbers of gametes and the production of large numbers of offspring (each has a lower probability of survival)

5

internal fertilization typically produce....

fewer offspring and invest considerable time and energy into raising offspring

6

r-strategist

a species that produces large numbers of offspring but provides few resources for their support

7

K-strategist

a species that produces relatively few young but invests considerable resources into their support

8

according to the model of r-stragetists and K-strategists, the environment places ______

selective pressures on organisms to drive them in one or the other direction

9

what environment did r-strategists evolve in?

unstable, changing, and unpredictable environments; advantage of reproducing quickly and producing many offspring

10

what environment did K-strategists evolve in?

stable, unchanging, and predictable environments; more crowding and larger populations; intense competition for limited resources so increased parental care and few offspring are favoured

11

age structure

the number of individuals within each age group of a population

12

what do ecologists use to understand past and predict future changes in populations?

ecologists use birth rates, expected longevity of individuals, and the proportion of individuals in a population that is able to reproduce

13

estimating the number of individuals of differing ages enables ecologists to predict....

whether the size of a population will increase or decrease

14

a growing population has what shaped distribution?

pyramid shaped distribution, larger young class than older class

15

a stable population has a ______ distribution of age classes

even

16

in humans, differences in age structures reflect....

socioeconomic variation among countries

17

differences in age structure in other species reveal...

threats from various sources

18

survivorship curves record changes in...

survival probability over an organism's life-span

19

demography

the study of the size, structure, and distribution of populations over time, including changes in response to birth, aging, migration, and death

20

cohort

a group of the individuals born at a given time (usually group that we begin our studies with)

21

life table

a table that presents information about how many individuals of a cohort are alive at different points in time (used to identify patterns of survival in population)

22

survivorship

the proportion of individuals from an initial cohort that survive to each successive stage of the life cycle

23

populations differ in the ages at which they experience the most ______

mortality

24

survivorship curve Type I

most humans and other large mammals survive their early years and show a steep decline in the last part of their life-span

25

survivorship curve Type II

small mammals and birds tend to lose numbers steadily throughout their lives

26

survivorship curve Type III

many Turtle Grass seedlings and those of most other herbaceous plants DO NOT SURVIVE THE EARLIEST PERIOD of life, but those that do survive show only slow additional declines over time

27

associate r-strategists with...

Type III survivor: r-strategists reproduce at rates approaching r, the intrinsic rate of growth

28

associate K-strategists with...

Type I survivor: population densities commonly lie near the carrying capacity K, when resources become scarce

29

r-strategists and K-strategists are on opposite ends of:

extremes-possible reproduction strategies in between can exist

30

life history

the typical patter of resource investment in each stage of a given species' lifetime

31

control over allocation of energy resources involves :

physiological trade-offs

32

the various ways in which animals and plants allocate resources to growth and reproduction is rooted in their:

physiological and their physiological traits are themselves, evolved traits