Humam activity affects: 4.0 Flashcards
Extirpation
A local extinction, or disappearance of a species from a particular area
Ex. Grizzlies used to be in the mountains of BC to the Manitoba prairies but now they are mainly found only in the mountains do to urbanization
Both the woodland caribou and the swift fix are extirpated from certain regions do to urbanization
Extinction
The disappearance of every individual of a species from the entire planet
Ex. Dinosaurs are extinct
Most mass extinctions are caused by catastrophic events such as volcanic eruption or anything sudden to the environment
Most extinctions are not mass and end over a long period of time
The biological diversity on earth is decreasing every decade
Natural causes of extinction and expiration
Natural selection is a slow process so when a species is no longer in a certain area or the world it is found over a long period of time through different environmental changes
Some of these changes: catastrophic events such as floods, lack of food do to overpopulation and disease
Not all extinctions take long periods of time… It depends on the event in which they are harmed
Over specialization
Organisms sometimes have adaptations that suit them only to s narrow set of environmental conditions. This can happen if their environment hasn’t changed in a long time
Another natural cause of extinction of their is a drastic change to their environment they will not be able to cope with the sudden change
Ex. Panda only eats bamboo shoots as it one from of food… If the food deteriorates the pandas will die off
Human causes of extinctions and extrications
Habitat destruction
Introduction of non-native species
Over hunting
Habitat destruction
Humans cause rapid changes to the habitats of organisms by constructing buildings, agricultural reasons, logging and damming the rivers of ecosystems
Ex. Clearing brush to create fields for our food source, ridding of species
Pollution often harms species and ecosystems by us using pesticides/fertilizers in our fields and they end up in a river where the animals drink or live
Habitat destruction is the worst in tropical areas because of the high level of diversity in species
Introduction of non-native species
Throughout history people migrate while bring new species of organisms with them along the way
Their than becomes comparison between species for resources as the communities become over populated with a number of different species
Ex. Seeds may be stuck in the fir of animals which get brought to foreign lands creating plant pests
Over hunting
Over hunting is the major reason for eventual extirpation in that area.
Ex. Passenger Pigeons were over hunted for sport making them die off, prairie dogs were over hunted by farmers for them ruining their land and hurting cattle
Effects of extinctions and extirpations
Reduce the number of biological diversity through the number of species
When a species disappears it affect other species who rely on that species for survival through niches or food chains
This overall affects the ecosystems that live off of each others niches
Artificial selection
The process of deleting and breeding nobody sod with desirable traits to produce offspring that have these desired traits
Opposite of natural selection because the human selects rather than the environment
Ex. Horse breeding has lots of artificial selection to get the right offspring, same in cattle for resources
Cloning
Taking a cutting from s plant and growing an identical plant through that cutting
Quicker way is removing cells from an individual plant with the right traits and put it in a Petri dish or bottle with the nutrients for it to grow another plant
Artificial reproductive technology
Artificial insemination: sperm harvested from a bull in livestock with the right traits is inserted into many female cows, more cows are fertilized at one time
In vitro fertilization: the speed cell from the prize bull is and eggs from the prize cow are combined in a Petri dish which produces an embryo which is than planted into a different cow
Genetic engineering
Refers to any technology that directly alters the DNA of an organism
This engineering is rapidly developing science and advance increases our ability to control the characteristics in organisms
Many methods involve inserting a gene from one species into another
Insulin is taken from cattle and used from medication for diabetics
A micro organism toxin called Bt for short is poisonous to insects, scientists insert this gene into the DNA of plants to make them produce that toxin
Risks in animals with biotechnology and genetic engineering
In agriculture, more and more livestock are looking the same by artificial selection… This reduces genetic variation in breeding
The scientists now can make an exact copy of an organism and by doing this over and over it is cloning the animals and making them all substantial to disease
Risks in plants with biotechnology and genetic engineering
With many crips they have found a way to make them resistant to pesticides and herbicides. They can now spray the crop but only kill the weed… This results in the cross breeding of crops and weeds by making the weeds now resistant to the chemicals
