Biology notes

Bacterial diseases

-> are caused by bacteria
-> include:- a) Cholera
b) Typhoid

HUMAN DISEASES
Disease: deviation from the normal functioning of the body

Categories of human DISEASES
1. Bacterial diseases
2. Protozoan diseases
3. Parasitic diseases

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TYPES OF POLLUTION
1. AIR POLLUTION
2. WATER POLLUTION
3. SOIL POLLUTION

POLLUTION
refers to release of substances of forms of energy into the environment by human activities in such quantities whose effects are either harmful to living organisms.

ADAPTATIONS OF HALOPHYTES TO THEIR HABITATS

1. Have salt glands
2. Have aerenchyma tissue
3. Have pneumatophores
4. Have sensitive chloroplasts
5. Have succulent tissues
6. Have root cells with high salt concentration
7. Have Hardy tissues

N/B: ALL THE ADAPTATIONS AIM AT ENSURING A BALANCE BETWEEN SALT AND WATER CONCENTRATION.
::: HALOPHYTES are plants that grow in saline(salt) water.

ADAPTATIONS OF HYDROPHYTES TO THEIR HABITATS

1. Have aerenchyma tissue
2. Have thin leaf lamina
3. They lack cuticle
4. Have sensitive chloroplasts
5. Their roots lack root hairs
6. Their flowers are raised above the water surface
7. Have long fibrous roots
8. Have leaves that are dissected into thread like straws
9. Have numerous stomata on the upper surface of the leaves.

N/B: ALL THE ADAPTATIONS AIM AT MAXIMISING WATER LOSS AND ENHANCE PHOTOSYNTHESIS
::HYDROPHYTES are plants that grow in water and water logged areas

ADAPTATIONS OF MESOPHYTES TO THEIR HABITATS

1. Have a thin cuticle
2. Have a broad lamina
3. Have mosaic leaf arrangement
4. Have air spaces in the spongy mesophyll
5. Have more stomata on the upper epidermis

N/B: ALL THE ADAPTATIONS AIM AT MAXIMISING WATER UTILISATION AND PHOTOSYNTHESIS
:: MESOPHYTES are plants that grow in normal environments (terrestrial plants)

ADAPTATION OF XEROPHYTES TO THEIR HABITATS
1. Have folded leaves
2. Have needle like leaves
3. Have thick waxy cuticle
4. Have sunken stomata
5. Have reversed stomatal rhythm
6. They shed their leaves during drought
7. Have succulent stems
8. Have reduced number of stomatas
9. Have hairy leaves
10. Have deep roots
11. Have short life cycle

N/B: ALL THESE ADAPTATIONS ARE AIMED AT MAXIMISING WATER UTILISATION.
:: XEROPHYTES are plants that grow in dry areas I.e deserts

METHODS OF POPULATION
ESTIMATION
1.
Quadrat method.
2.
Line transect.
3.
Belt transect.
4.
Capture-recapture method.

POPULATION.

is a group of organisms belonging to the same species in a particular habitat.

Characteristics of a population.
1.
Population density
2.
Population dispersion
3.
Population growth rate

Adaptation of small intestaine

Explain why potatoe tuber become sweeter after boiling?

PYRAMID OF BIOMASS.
 This is a diagram drawn to represent
the dry mass of organisms at different
feeding/trophic levels.

INVERTED PYRAMID OF NUMBERS
 It is obtained when the number of organisms does not decrease in succeeding trophic levels

Example.
 The following table shows the estimated number of organisms recorded in a farm.
●Small fish- 3,500
●Microscopic algae- 12, 000
●Crocodiles-100
● Large fish- 950
● Mosquito larvae- 8, 900

PYRAMID OF NUMBERS.

 A pyramid of number is a diagram which represents the total number of organisms at different trophic levels

GIVEN THE DIAGRAM BELOW
a) Construct a food chain ending with
crocodile as a quaternary consumer.

b)Name the organism in the food web that
has only one predator.

FOOD WEBS

 A food web consists of many food chains.

FOOD CHAINS

 A food chain is a linear representation of the flow of energy from the producers to consumers and to the decomposers.

 Examples include:
a)
Grass -----> Grasshopper ----> Bird
b)
Napier ---> grass ---> Goat ---> Man

 The arrow points to the eater.

ENERGY FLOW IN THE ECOSYSTEM.

 Energy flow is the flow of chemical energy in feeding from one feeding level to the other.

● these levels are called trophic levels

● energy flows in the following form;

PRODUCERS ----> CONSUMERS

○ The sun is the main source of energy
○ PLANTS are the producers
○ CONSUMERS are majorly carnivores. And range from primary upto but not limited to quaternary consumers

Nitrogen cycle

BIOTIC FACTORS
Include;

Predation/ predator-prey relationship
Parasitism
Symbiosis
Competition
Saprophytism

ABIOTIC FACTORS
Include:

Light
Temperature
Wind
Relative humidity
Salinity
Atmospheric pressure
Topography

FACTORS IN AN ECOSYSYEM.

A. ABIOTIC FACTORS/ NONLIVING FACTORS
B. BIOTIC FACTORS/ LIVING FACTORS

Application of knowledge gained from ecology

i.
Sustainable food production.
ii.
Conservation of natural resources.
iii.
Pollution control.
iv.
Control of pests and diseases.
v.
Prediction of climate change.
vi.
Population control.
vii.
Ecotourism

Definition of terms

7.Ecological niche
- this is the position that an organism occupies in the ecosystem

8.Population
- refers to all members of a particular species in a particular habitat at a particular time

9.Community
- refers to all organisms belonging to different species that interact in the same habitat.

10.Ecosystem
- it is a natural unit composed of abiotic and biotic factors whose interactions lead to a self-sustaining system e.g. a pond.

11.Biomass
- this is the total dry weight of living organisms at a particular feeding/ trophic level.
zebras in a park.

12.Carrying capacity
- refers to maximum number of organisms an
area can comfortably support without depletion of available resources.

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TOPIC TWO: ECOLOGY

Definition of terms

1.Ecology:
is the study of interrelationships of organisms to each other and with their environment.

2.Environment
constitutes the surroundings of the organisms
both living (biotic ) and nonliving (abiotic or physical)

3.Autecology
is the study of single species.

4.Synecology
is the study of different species .

5.Habitat
- this is a specific place/locality with a particular set of conditions where an organism lives.

6.Biosphere/ ecosphere
- this is the part of the earth and the
atmosphere inhabited by living organisms.

Next up: ECOLOGY