environmental biology & genetics factors affecting the variety of species in an ecosystem. m r g...

Environmental Biology & Genetics

Factors Affecting the Variety of Species in an Ecosystem.

Mr G D

avidson

Mr G D

avidson

Monday, April 10, 2023 2Mr G Davidson

Biodiversity

Each species in a habitat or ecosystem has its own role to play and this role is called its niche, e.g. an owl would occupy the niche of “small mammal-eating bird of prey”.


Biodiversity

Organisms from different niches have special features which allow them to be successful and these features are called adaptations, e.g. behaviour, body structure, etc..

Darwin’s FinchesCharles Darwin investigated the finch population of the Galapagos Islands in the 1830s.


On each island there is a different food source.He found that the beaks of the finches there had adapted to suit the diet of the birds.

Desert Plants

To survive in deserts plants have to adapt to reduce water loss.


Roots go deep in the soil to find water.

Leaves are reduced to spines to reduce evaporation.

Surfaces are covered with a thick waxy cuticle.


Biodiversity

Biodiversity is the range of species which exists within an ecosystem.

A stable ecosystem: Contains a wide variety of species. Can exist for a very long time. Is not affected by small changes.


Biodiversity

Biodiversity is very important to humans in a number of different ways:Importance Example

Food Fish, wheat, etc

Medicines Morphine from opium poppy

Raw Materials Wood, cotton, etc..

Recreation Hill walking, diving, etc..

Genetic material

Disease-resistant crops


Habitat Destruction

Human activities such as agriculture, construction and industry have lead to huge areas of natural habitat being cleared.

This clearing has lead to the destruction of habitats and has drastically reduced the biodiversity of these areas.


Habitat Destruction

Deforestation occurs in many parts of the world today, e.g. the Brazilian rainforests.

This results in: Erosion of the land and loss of fertility in

the soil. Reduction in biodiversity. Changes in climate.

Habitat Destruction

Pollution results in such things as acid rain being produced from sulphur

dioxide killing fish and trees. untreated sewage being released into

rivers which causes the number of invertebrate species to decrease.



Habitat Destruction

These have lead to a “Biodiversity Crisis” which is resulting in some species becoming extinct, e.g. Dodo Black rhinoceros Giant panda Blue whale Snow leopard


Habitat Destruction

Grazing can also have a major effect on biodiversity, e.g. Over-grazing can lead to plant species

being destroyed. Under-grazing can lead to a small

number of very vigorous plant species becoming dominant.


Behavioural Adaptations

All animals show behavioural adaptations.

These are responses to changes in the environment called environmental stimuli.

Such responses are called behavioural responses.



Examples of behavioural responses include: Sea anemones are responsive to touch. Blowfly larvae are responsive to light. Swallows are responsive to daylength. Earthworms are responsive to

vibrations.



These behavioural responses are important to the survival of the organism, e.g. Woodlice move towards conditions

which are damp and dark and this is of “survival value” because:The damp conditions prevent the organisms

from drying out.The darkness protects them from predators.

Resources

Every species needs certain resources (essential materials) from the environment to survive. E.g we need food, water, warmth and

shelter. When any resource is in short supply

there will be competition for it.



Competition

Competition occurs when a number of organisms require the same resource.

Competition between members of the same species is very intense because they are competing for the same resource.


Competition

Competition between members of different species is less intense because they are not always competing for the same resource.

In such cases a compromise is often reached to reduce the competition.


Competition

Plants compete for such things as: Light Space Water Nutrients

Animals compete for such things as: A mate Territory Food shelter

environmental biology & genetics factors affecting the variety of species in an ecosystem. m r g...

Documents

mr g davidson slide

mr g davidson roots

range of species

members of different

biodiversity crisis

number of invertebrate

d s o n slide

wide variety of species