Population Ecology or Demecology

Июль 21, 2022

Главная
Английский язык
Population Ecology or Demecology

Содержание

2. PLAN Static characteristics of the population Dynamic characteristics of the population Factors dependent on population density
3. Population ecology is the study of how the population sizes of species living together in groups
4. Population means the members of a species living together in a particular locality for a long
5. Population
6. Populations has certain environmental characteristics, which are not seen in some of its members, namely: a
7. Ecological niche is a set of all the requirements of populations to environmental conditions (structure and
8. Static characteristics of the population Рopulation size is the number of individuals organisms in a population.
9. The population size is intimately associated with the population biomass, which is its major characteristic. In
10. Density - is the population size, per unit of space it occupies. For example, density of
11. Dynamic characteristics of the population The dynamics of the population size is seen at interaction of
12. Fertility means ability to increase the population or the number of offspring produced by one female
13. Maximum birthrate is a theoretically maximum number of species produced under ideal conditions in the absence
14. Mortality means the death of individuals per time unit in the absence of limiting factors.
15. Ecological, or realized mortality means the death of individuals per time unit under actual environmental conditions.
16. Both mortality and fertility vary greatly with age. For this purpose, the ecological mortality is determined
17. The first type is characteristic to many mammals and humans and reflects a lower mortality rate
18. Immigration is new individuals which are arrived from other populations
19. Emigration is some individuals which gone outside of this population area.
20. Growth of the populations Population growth occurs when birth rates exceed death rates or immigration exceeds
21. Types of growth
22. The reasons for decreasing population Population size increases and decreases over time. There are factors such
23. Often, human being or anthropogenic factor (reduction in food supply, reducing the oxygen in the water
24. Factor impacting the mortality. Factors impacting the population fertility and mortality act more effectively if there
25. Factors dependent on population density If population density is high: lack of food; increase in the
26. There are factors that are independent of the population density: The impact of unfavorable weather conditions
28. Скачать презентацию

Слайд 2

PLAN
Static characteristics of the population
Dynamic characteristics of the population
Factors dependent

on population density
Factors independent on population density

Слайд 3

Population ecology is the study of how the population sizes of

species living together in groups change over time and space.

Слайд 4

Population means the members of a species living together in

a particular locality for a long time (a large number of generations) and able to interbreed freely (panmixia).

Слайд 5

Population

Слайд 6

Populations has certain environmental characteristics, which are not seen in some

of its members, namely:
a distinct niche occupied by the population;
abundance and biomass of the population;
dynamic characteristics of the population - fertility, growth rate, mortality, and survival.

Слайд 7

Ecological niche is a set of all the requirements of populations

to environmental conditions (structure and modes of environmental factors) and locations where these requirements are fulfilled.

Слайд 8

Static characteristics of the population
Рopulation size is the number of

individuals organisms in a population. The population size can vary considerably in different organisms. Typically, population of large animals is relatively small and may consist of several hundred members; population of small organisms (invertebrates, unicellular organisms) can reach millions of species.

Слайд 9

The population size is intimately associated with the population biomass, which

is its major characteristic. In particular, biomass of plants and animals is used by human being, that is why the rate of biomass growth is critical for both organism and practical need. In agriculture and forestry the damage caused depends on herbivores species numbers.

Слайд 10

Density - is the population size, per unit of space it

occupies. For example, density of the moose and other large animal populations is determined by the number of individuals per 10 thou.ha, soil invertebrates population is calculated per 1 m2.

Слайд 11

Dynamic characteristics of the population
The dynamics of the population size

is seen at interaction of four major population-dynamic processes:
1) fertility ;
2) mortality;
3) emigration
4) immigration

Слайд 12

Fertility means ability to increase the population or the number of

offspring produced by one female per 1 year.

Слайд 13

Maximum birthrate is a theoretically maximum number of species produced under

ideal conditions in the absence of limiting factors, and reproduction is limited to physiological factors.
Ecological, or realized birthrate is birth of new species under actual environmental conditions.
Anthropogenic impacts on the population can change the birthrate

Слайд 14

Mortality
means the death of individuals per time unit in the

absence of limiting factors.

Слайд 15

Ecological, or realized mortality means the death of individuals per time

unit under actual environmental conditions.
The difference between fertility and mortality is a certain resulting parameter that determines the actual dynamics of a given population size.

Слайд 16

Both mortality and fertility vary greatly with age. For this

purpose, the ecological mortality is determined for various environmental groups and survival curves, which are divided into 3 main types are drawn.

Survival curve
Highly convex
Intermediate
Highly concave

Слайд 17

The first type is characteristic to many mammals and humans and

reflects a lower mortality rate in all age groups.
The second type characterizes a relatively constant mortality in all age groups (birds, mice, rabbits, etc.).
The third type reflects high mortality in the early stages of development (ontogeny) (molluscs, butterflies, etc.).
The survival curve depends on the parental care level.

Слайд 18

Immigration is
new individuals which are arrived from other populations

Слайд 19

Emigration is some individuals which gone outside of this population area.

Слайд 20

Growth of the populations
Population growth
occurs when birth rates exceed death

rates or immigration exceeds emigration.

Слайд 21

Types of growth

Слайд 22

The reasons for decreasing population
Population size increases and decreases over time.

There are factors such as:
resource availability;
competition;
parasitism
predation;
Climate;

Слайд 23

Often, human being or anthropogenic factor (reduction in food supply, reducing

the oxygen in the water in case of eutrophication, etc.) cause exhaustion of needed populations.

Слайд 24

Factor impacting the mortality.
Factors impacting the population fertility and mortality

act more effectively if there is increased population density. Such factors are called dependent on population density

Слайд 25

Factors dependent on population density
If population density is high:
lack

of food;
increase in the number of enemies, and morbidity.
members are physically weaker and smaller;
Animals birthrate reduces, even if there is no food-deficiency.

Слайд 26

There are factors that are independent of the population density:
The

impact of unfavorable weather conditions (severe winters, droughts);
natural disasters (fire, earthquake, flood, hurricane, etc.) may serve an example.