Ecology Flashcards
(88 cards)
1
Q
Population ecology:
A
- the study of population in relation to their
environment. - How biotic and abiotic factors influence the abundance,
dispersion and age structure of populations.
2
Q
population
A
a group of individuals of a single species living in the same area that can interbreed and produce fertile offspring
3
Q
Density:
A
the number of individuals (of a pop) per unit area or volume
Changes as individuals are added or removed from a population via births and deaths (natality and mortality) and emigration and immigration
4
Q
Dispersion:
A
pattern of spacing among individuals within the boundaries of the pop.
5
Q
Clumped:
A
- Individuals aggregate in patches because the resources are
rife there and they are better able to survive - May also be due to mating behaviour
- Where they can breed effectively
- Increases the predation or defence of the group
6
Q
Uniform:
A
- Evenly spaced pattern or dispersion
- May be because organisms are territorial and need space from other individuals
7
Q
Random:
A
The position of everyone is independent of
other individuals
8
Q
demographic
A
how the abiotic and biotic factors influence pop density and dispersion as well as
immigration, emigration, natality and mortality
- Statistics of a pop and how they change over time
9
Q
Life table
A
summaries the survival and reproductive rates of individuals in specific age groups
10
Q
Survivorship curves
A
- made from life tables
- useful when there is not a lot of emigration or immigration as it
shows how a population changes over time. - Reproductive rates can also be used insuch a population.
11
Q
R- type survivorship curve
type 3
A
- low parental care -> fewer offspring survive into adulthood
- high number of offspring produced
e. g. trees, barnacle, fish
12
Q
K-type survivorship curve
type 1
A
- > more offspring survive into adulthood
- few offspring
- high prenatal care
e. g. humans, elephants etc.
13
Q
Type 2
A
constant death rate in the organism’s life
e.g. birds, rodents, lizards
14
Q
reproductive rates
A
proportion of females weaning a litter x mean number of females in a litter = average number of female offspring
15
Q
exponential growth model
A
Populations expand greatly when resources are abundant, and the resources start
reducing compared to population size
change in population size = births + immigrants entering the population - deaths - immigrants leaving the population
(LOOK AT EQUATIONS ON PRINTED NOTES)
16
Q
Exponential growth:
A
The population increases at a constant rate per individual = J shaped
growth curve
17
Q
Logistic model growth
A
population grows more slowly as it nears carrying capacity
LOOK AT PRINTED NOTES
18
Q
A S-shaped graph is produced
A
The pop increases exponentially and then levels out at carrying
capacity
19
Q
Assumptions of the logistic growth model:
A
-Populations don’t just adjust to a new environment and grow according the
model
-There is a lag effect
20
Q
Life history traits are produced by natural selection
A
There are trade-offs between survival and reproductive traits (frequency of
reproduction, number of offspring, investment in parental care)
21
Q
life history
A
Traits that affect an organism’s schedule of reproduction and survival make up its
22
Q
Diversity of life histories:
A
Organisms also differ in:
- How many offspring they produce (one or many)
- How often they reproduce
23
Q
Semelparity:
A
- Reproduce once off with lots of offspring and then
dies - Organisms that live in environments that are
unpredictable
24
Q
iteroparity
A
- Repeated reproduction
- Environment is predictable, and they can depend on it
25
Trade-offs and life histories:
Organisms need to choose between conserving their energy to grow
themselves or to produce offspring
There is a trade-off between offspring number and the amount of resources
a parent can devote to each offspring
26
Number of offspring:
Large number of offspring with no parental care = many individuals
survive even if some are lost
27
Size:
1. Smaller organisms are formed = less energy to give each offspring
therefore many small are formed
2. Smaller organisms are formed so that they can be cared for by
parents and they can grow
3. Organisms with high levels of being predated produces large amounts of
offspring to increase the survival likelihood
4. Increased parental care increases the change of offspring survival
28
Logistic model and life history:
| Look at printed notes
1. K - selected species
Density dependent
Produce and live in areas with limited resources
Organisms can extract resources better when the resources are low
There population size doesn’t fluctuate as much
E.g.: humans, mammals with parental care
2. R- selected species
Density independent
Live and produce in areas with maximum resources
These organisms produce lots of offspring
Resources aren't limited
Organisms overshoot carrying capacity and fluctuate there
E.g.: trees, barnacles, fish
29
Population change and population density:
Population grows when birth rate > death rate
30
Density independent regulation:
A birth rate or death rate that doesn’t change with population
density
E.g.: climate, temperature, salinity, precipitation
31
Density dependent regulation:
Birth rate that decreases with a rising density or a death rate that
increases with an increase in population density
E.g.: predation, disease, competition for resources, waste,
competition for waste, space (territoriality)
32
Positive feedback
- between population density and the rates of births and
death
- Helps stabilise a population
33
Negative feedback
between density dependent factors and population
| density
34
Population dynamics:
Fluctuation of size of a population from place to place or time to time
35
Predator prey relationship:
Predator population never reaches the highs of the prey and they lag
behind the prey’s fluctuations
36
Immigration, emigration and metapopulations:
When a pop becomes crowded and resource competition increases
Emigration increases
37
Metapopulations:
```
occupy patches of suitable habitats in a place with lots of
unsuitable habitats
Patches vary in size,
quality and isolation
from other patches
If all individuals from
a patch die, then
they will be
occupied by
immigrants from
other patches
```
38
Global human population:
- The human population is growing faster than exponential growth
- During the agricultural revolution = movement of humans to different
countries of the world
Created food sources for people to live, survive and reproduce
- Plagues decreased the population
- Industrial revolution caused population to increase as there was a rapid
increase in the amount of food produced
39
Regional patterns of population change:
Zero pop growth = birth rate – death rate -> stable pop’s growth
40
Demographic transition:
1. Transition from high birth and death rate to low birth and death rate
zero pop growth = high birth rate - high death rate
↓
zero pop growth = low birth rate - low death rate
2. This is caused by improved living conditions and industrialisation,
increase in the quality of health care, improved access to education
especially for women
3. Populations are declining because reproductive rates are below the
replacement level:
- Change this by increasing the birth rate or immigration
4. Education, delating marriage, contraception = moves more populations
towards zero pop growth
41
Age structure:
The relative number of individuals of each age in a population
42
Rapidly growing population:
1. The base is very large, and they will grow up to reproduce and cause
more growth in the population
2. Triangle shaped
- Shows:
Employment and education problems will continue into the
future
43
Slow growing population:
1. Even growth from the base till post-reproductive stages
2. Rectangular shaped
- Shows:
The younger generation will be supporting the older
generation “boomers” in future
44
No growth population:
1. Small base
2. Individuals younger than the reproductive age are under represented
3. The population will decrease in the future
4. Bell shaped
Shows:
The younger generation will be supporting the older
generation “boomers” in future
45
Infant mortality
- the number of infant deaths per 1000 live births
- The higher the lower the quality of life faced by children at birth
- Parents want to make more children to ensure some reach
adulthood
46
Life expectancy at birth:
the predicted average length of life at birth
the lower the life expectancy the more they are affected by disease,
poor infrastructure, social upheaval
47
limits in human population size:
Increase in population increases the demands of resources (land, food, work,
disease spread, fuel, building materials etc)
48
Ecological footprint:
Land, water and resources required by each person, city or nation to
produce all the resources it consumes and to absorb all the waste it
generates
Use energy use to determine this as well
Estimates how close we are to the earth’s carrying capacity
49
Competition -/-:
Individuals of different species compete for resources that limits the survival
and reproduction of each species
50
Competitive exclusion:
One species grows to their carrying capacity and the other dies off
(inferior competitor)
51
Ecological niche:
the specific set of biotic and abiotic resources that an
| organism uses in its environment
52
Sympatric populations
= geographically overlapping
Have to change their structure to use resources so as
not out outcompete or be outcompeted
53
Allopatric populations
= geographically separate
| Use similar resources and are geographically similar
54
Predation +/-:
One species is the predator and the other the prey
The predators have developed adaptations to help them catch prey and the
prey have developed adaptations to escape from the predators
They both evolve in the process = evolutionary arm race =
coevolution:
55
coevolution:
The most efficient predators are able to get the predators
and thus survive and reproduce
The prey which escape the clutches of the predators are able
to survive and reproduce
56
Herbivory +/-:
- A herbivore eats the plant by harming it
- Plants may develop thorns, toxins etc.
- Herbivore develops a way of finding out which is the most nutritious food to
be eaten
57
Parasitism +/-:
The parasite derive nourishment from another organism (host) and harms it
in the process
58
Endoparasites:
Parasites that live in the host
59
Ectoparasites:
Parasites that live outside of the host
60
Mutualism +/+:
- Benefits both species
- Each species depends on the other for survival, but some can survive on
their own
- Both species provide things to the other
61
Commensalism +/0:
One species is helped by the other which is not benefitted nor harmed
62
trophic structure
1. Feeding relationships between organisms
2. Plants and autotrophs are primary producers that transfer food energy
upwards to the herbivores (primary consumers) -> carnivores (secondary,
tertiary and quaternary consumers) -> decomposers
3. This forms a food chain where each position an organism occupies is called a
trophic level
63
Food webs:
Interconnected food chains
64
Species with large impact:
Species that are abundant or play a pivotal role in community dynamics
65
Dominant species:
Species with a lot of individuals
66
Key stone species:
Have an important ecological role
| They may not be very dominant
67
Ecosystem engineers:
- Transform the landscape and ecosystem so it is suitable for the
populations in it
- They do this by felling trees, making ponds, digging etc.
68
Bottom-up control:
- Unidirectional influence from lower to
higher trophic levels
- Bottom levels control top levels
69
Top-down control:
- Predation controls community organisation
| - Predators limit herbivores and herbivores limit plants
70
Biomanipulation:
Helps prevent algal blooms by altering the density of
higher level consumers
Eg: removing the fish allows the zooplankton to
increase in numbers and this decreases the algal
density
71
Biological control:
Controlling of pests (insects, mites, weeds etc.) using
other organisms that will resort to predatory, herbivory,
parasitism or other mechanisms to decrease its
proliferation and negative effects
72
Epidemiology:
Understanding disease, the patterns of disease and developing intervention
strategies
73
Disease ecology:
Understanding the distributions, emergence, distribution of diseases and
environmental and ecological determinants of disease
74
zoonotic disease
1. Diseases that are transferred to humans from other animals through direct contact
with the infected animal or an intermediate species (vector)
- Vectors are mostly parasites
2. Identifying the community of hosts and vectors helps prevent illness
- Helps control the host that spreads the disease and prevents the
vector coming into contact with the host
75
reservoir habitat
```
Animals that carry the disease
- Pathogens come into
contact with the reservoir
- Pathogens immigrate from the
reservoir to the vertebrate body
where they cause a disease
```
76
Diseases emerge because of:
1. human population growth
2. having exotic pets
3. poor awareness of disease
4. land use changes
5. climate change
6. bushmeat trade
77
Stages of pathogen evolution:
a. Viruses are transmitted by the reservoir only
b. Starts getting transmits through humans
c. Pathogen evolves into a different form and can be transmitted
to humans by humans
- Easy for humans to get diseases from primates = we share a lot of
our genome
- Body becomes the ecosystem = in which the pathogen can survive
Introducing antibiotics and vaccines = natural selection
pressure
78
Globalisation:
```
Past = humans couldn't travel, and epidemics were confined to small areas
Today = people can travel easily and transmit diseases from place to place
```
79
SARS:
Caused by coronavirus and produces flu-like symptoms
Chinese rufous horseshoe bat transfers the virus to masked palm
civet and then to humans
Causes: bush meat, globalisation
80
The importance of niche:
Find the environmental factors that the reservoirs need to live with the
pathogen
- Helps predict the disease outbreak in other areas
81
Chagas disease:
1. Caused by protist carried by an (carried by rodents) insect that poos on
skin and causes an itching which when scratched enters the body
2. Rodents carry the bugs live close to each other and the protist can be
easily transmitted
82
Malaria in Sahel region:
- Rain arrives and the population of the mosquito increases
- Migration of mosquitos to areas with water sources from the rain
- The mosquitos live far from the dry region and travel there
- Aestivation - hibernating
- Mosquitos sleep during the high temperatures and dry times
83
Control:
1. Chemical and biological control
2. Larvicides/adulticides
3. Mosquitofish
Eat the larvae of the mosquito
84
Avian influenza (H5N1 virus) and bird migration:
Water birds migrate a lot globally and carry this virus from place to place
85
Water pollution:
Critical load in water increases due to human waste -> eutrophication
-> harmful algal bloom
Too many nutrients in the water due to human waste (from fertilizer
etc.). algal blooms occur due to the increase in nutrients and
sunlight. The water body becomes covered in algae
Prevents sunlight entering the lower levels of water and algae
use up all the oxygen
86
Biological magnification:
Organisms in the lower trophic levels consume or are exposed to chemicals
and toxins
The toxins may be consumed in small quantities and may not affect
the organism that consumes it
Organisms in higher trophic levels consume those animals and are affected
by those toxins
Have a higher concentration of the toxins
The concentration builds up going up the trophic levels
Biological magnification = building up of toxins in organisms in trophic levels
E.g.: DDT
Goes into the water -> consumed by zoo plankton -> small fish eat
the zoo plankton and consume a higher concentration of DDT ->
larger fish eat the smaller fish -> birds eat the fish with the higher
concentration of DDT and have a lot of the DDT in their diet due to
the accumulated DDT concentration
87
Acid rain:
Rain has high levels of nitric and sulphuric acid
Burning fossil fuels -> sulphur dioxide and nitrogen oxides are released into
the atmosphere -> react with water and oxygen and form nitric and
sulphuric acid -> during precipitation it falls with the rain water
Effects:
1. Makes water bodies more acidic
2. Aluminium is absorbed from the soil
3. Toxic conditions are created, and aquatic animals are affected
88
Climate change:
```
Gases that cause the greenhouse effect
1. Water vapour
2. Carbon dioxide
3. Methane
4. Nitrous oxide
5. Oxone
6. Chlorofluorocarbons
7. Hydrofluorocarbons
- The gases cause more heat to be trapped in the earth’s atmosphere and
causes a change in climate, increase in water levels due to ice caps melting
- Due to climate change more diseases emerge from the icecaps = zombie
viruses are released
```
- Diversity decreases because organisms cannot survive properly in the fast-
changing environments
