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Bases of Biological Sciences. Ecology

1.

Bases of Biological Sciences
Lecture 6
Ecology

Ecology
• Ecology is the scientific analysis and study of
interactions among organisms and their
environment
• Put individual organisms together, they can
interact with each other and their
environments to create something larger than
the sum of this parts

3.

Hierarchy of biological systems
• Tiers of ecological order:
–
–
–
–
–
–
–
–
–
–
–
–
Molecule
Organelle
Cell
Tissue
Organs
Organism
System of organs
Population
Biocenoses
Ecosystems
Biome
Biosphere

4.

Population
• Population is a summation of all
the organisms of the same group or species,
which live in a particular geographical area, and
have the capability of interbreeding
• Density of population:
– born and immigration (+)
– death and emigration (-)
– dispersion
– fecundity

5.

Population growth
• Limiting factors of population growth:
– food
– temperature
– mates
– space
• Limiting factors:
– density-dependent
– density-independent

6.

Population growth
• Carrying capacity of habitat is the maximum
population size of the species that the
environment can sustain indefinitely, given the
food, habitat, water, and other necessities
available in the environment

7.

Population waves

8.

9.

Community
• Community (biocenosis) is an assemblage
or association of populations of two or more
different species occupying the same
geographical area and in a particular time.

10.

Interspecific interactions
• Predation – the predator species benefits while the prey
species is harmed (+/-)
• Competition – species can compete with each other for
finite resources
• Mutualism – interaction in which both species benefit
(+/+)
• Parasitism – one species, the parasite, benefits at the
expense of the other, the host (+/-)
• Commensalism – one organism benefits while the other
organism is neither benefited nor harmed (+/0)
• Amensalism – a product of one organism has a negative
effect on another organism (+/-)

11.

1
2
3
4
5

12.

Community ecology
• Community ecology studies how the
interactions between community members
and their environment affect how much of
each species there are within a community

13.

14.

Ecosystem
• An ecosystem is a community of living organisms in
conjunction with the nonliving components of their
environment (things like air, water and mineral
soil), interacting as a system
• Ecosystem ecology explores how energy and
materials flow through an ecosystem, and how the
physical environment impacts the living organisms
• A habitat is an ecological or environmental area
that
is
inhabited
by
a
particular species of animal, plant, or other type
of organism. Habitat provides area (living or nonliving)

15.

Food chain
• Food chain is a succession of organisms in an ecological
community
that
are
linked
to
each
other
through the transfer of energy and nutrients
• Producers
• Consumers:
–
–
–
–
primary (herbivorous)
secondary (carnivorous)
tertiary
final
• Decomposers (Detritivores)

16.

17.

18.

19.

Ecological pyramid
• Biomass is the mass of living biological
organisms in a given area or ecosystem at a
given time
• Ecosystem productivity is the rate of
generation of biomass in an ecosystem
• Ecosystem efficiency describes
the efficiency with which energy is
transferred from one trophic level to the next

20.

Ecological pyramid
• Ecological pyramid
is a graphical
representation
designed to show
the biomass or bio
productivity at
each trophic
level in a
given ecosystem

21.

22.

Biome
• A
biome
is
a
formation
of plants and animals that have common
characteristics due to similar climates and can
be found over a range of continents
• Usually a biome is named after its predominant
vegetation association:
– grassland
– rainforests
– tundra
–…

23.

Biome vs Ecosystem
• A biome encompasses numerous smaller-scale
ecosystems and is general and global
• A biome is the biotic community of a large-scale
ecosystem, the abiotic components are implied
as the shaping factors of a biome

24.

Shaping factors
• Extreme (high, low), moderate:
– Water (rainfall, precipitation)
– Temperature (sunlight, air, ocean flows)

25.

1
3
2
Temperature
Water
------------------Biodiversity
5
6
4

26.

Diversity of biomes
Temperature
Plants
Animals
Water

27.

28.

Biosphere
• The biosphere is the global sum of
all ecosystems
• The living organisms are affected by both
biotic and abiotic factors they live within
• In their turn, they change the environment:
climate, chemical makeup, geology of our
planet

29.

Ecological problems

30.

Vocabulary 6
hierarchy
tiers
fecundity
biocenosis (pl. biocenoses)
predator
prey
host
parasite
to benefit
at the expense
to harm
environment
encompass
shaping factor
tundra
taiga
rainforest
steppe
desert
prairie
savanna
coniferous forests
habitat
biotic and abiotic factors
rainfall
precipitation
moderate/extreme temperatures
producers
consumers
decomposers
detritivore
herbivorous animal

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