Ch 8-9Population Chages & Interactions Flashcards Preview

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Flashcards in Ch 8-9Population Chages & Interactions Deck (31):
0

Populations of organisms are......

Dynamic.

Can assess the health of animals or entire species

1

Population size

The number of organisms

2

Population density

Calculated by dividing the number of organisms (n) by the total area (A) or total volume (V)

3

Population distributions

Clumped dispersion
Uniform dispersion
Random dispersion

4

Factors that affect population change

Only 4
1. Natality - # of births
2. Mortality - # of deaths
3. Immigration - "in" move in
4. Emigration - "exit" move out

5

Growth rate:
(Gr)

Describes how quickly a population is increasing or decreasing

Gr =

6

Per capita growth rate:
(cGr)

Represents the change in a populations size relative to the initial population size.

cGr=

7

Population growth models

-open population
-closed population
-exponential growth
-environmental resistance
-biotic potential
-density ~dependent factors
-density ~independent factors
-intra~specific competition
-inter~specific competition

8

Open population

Allows things to enter and leave

9

Closed population

Does not allow things to enter or leave

10

Exponential growth

Size increases as a fixed rate per time

11

Environmental resistance

Any factor limiting a populations ability to reach it's biotic potential.

12

Biotic potential

Maximum # of offspring a species could produce with unlimited resources

13

2 types of growth curves that show population growth.

J-shaped
S-shaped

14

4 phases of growth curves (J-shaped & S-shaped)

1. Lag phase
2. Growth phase
3. Stationary phase
4. Death phase

15

Density-dependent factors

Influences a population due to its density.

Ex. Disease or predators

16

Density-independent factors

Influences a population regardless of density.

Ex. Fire or flood

17

Intra-specific competition

Interaction between the same species.

Duck&Duck

18

Inter-specific competition

Interaction between different species.

Duck&geese

19

K-selected strategy

Few offspring, more parietal care
Usually larger, longer life span

Elk, elephants, humans

S-shaped curve

20

R-selected strategy

Many offspring, little to no parental care
Usually smaller, short life span.

Mosquito

21

Predator prey cycles

Mimicry
Camouflage

22

Symbiosis

3types

A relationship in which organisms of two different species live in close, usually physical contact.

-Parasitism
-Commensalism
-Mutualism

23

Parasitism

One benefits and the other is harmed

24

Commensalism

One benefits and the other doesn't care

25

Mutualism

Both organisms benefit

26

Succession:

2types

the slow replacement of one community of plants by another.

Primary succession
Secondary succession

27

Primary succession

-Plants take over an area not previously covers by plants.
-due to the lack of nutrients

28

Secondary succession

-Plants take over an area that was pervious lay covers by plants.
-faster due to availability of nutrients.

29

Pioneer community

-first plants to arrive during succession...
-weeds

30

Climax community

These are the last plants to arrive