PART 2 - Mechanisms of population change Flashcards
Variation is..
the differences that may be observed in an organism
There are visible (example: color) differences and invisible (example: Biochemical) differences.
Variation can occur between different species, this is called..
InTERspecific variation
Variation can also occur within the same species, this is called..
inTRAspecific variation
There many species on earth, majority of them are plants, insects and microorganisms. How many different species are there on earth?
8.7 million different species
Nearly 10,000 new species are discovered every year
Variation can be passed on from one generation to another (the differences on an organism). If the variation are passed on and are advantageous to the population, they are called..
Adaptation (example: Finches on an island with resources deep within the ground. Finches with longer beaks will be able to survive unlike the ones with wider beak. Years on, the island will consists of only long beak finches)
What is adaptation?
Change or the process of change (change to suit the environment)
There are 3 types of adaptation, list them..
Structural, behavioural and physiological
One of the 3 types of adaptation, structural adaptation is..
the physical features of an organism (such as the beak of a bird or the fur of a bear)
One of the 3 types of adaptation, behavioural adaptation is..
the behaviour of organism to the environment (example: a cat hissing when threatened)
One of the 3 types of adaptation, physiological adaptation is..
A response to the environment from an individual external stimulus in order to maintain homeostasis (example: shivering when cold)
The variation within species results from..
the genetic changes and recombination / mutations in DNA (A mixing of genes can occur during sexual reproduction)
These genes come from 50% from the mom and 50% from the dad
What causes variation to arise? (genetic changes and recombination)
Mutation and it continuously happen in the DNA
What are some of the results of mutation? (list 4)
Exhibition (display) of new characteristics, death of cells, malfunctioning cells, multiplying of more cells with mutation (this results in a tumour).
Mutations does not only occur when organism are developing, they also occur a..
after birth. Mutation occurs to fit the environment.
After birth, mutation can still occur within the organism, where does it occur and what is their names? (there is 2)
Somatic (body) cell mutation
- Disappear when with organism during death
Reproductive cell (gamete) mutations
- Get passed on to next generations
- Lead to variations
- Can lead to selective advantage
What is natural selection?
The idea that genetic mutation or variation that are advantageous are most likely to be passed on to offspring
The environment will exert selective pressure on a population towards certain traits
What is malaria?
a illness that cause death
When malaria was present in Africa, how did this illness get spread?
Mosquitoes carry blood that contains illness and infect a person when it bites
What does an individual need to be immune to malaria?
Sickle cell anemia
Today, Africa now contains most individual with sickle cell anemia. This is natural selection at work
What is the process of evolution?
Over time, populations of the same species that are exposed to different environmental pressures can become so genetically different that they can no longer be classified as the same species and be used to interbreed; that is, they now have become two different species
What is the cause of evolution?
natural selection within an environment
What are the two theories of evolution?
Lamarck’s theories and Darwin’s theory
One of the theories of evolution, Lamarck’s theories consists of 3 theories which are..
Theory of need
- Organisms change because they need to change (Example: our environment changed, ancestors of the snake needed to squeeze through narrow spaces so it stretched its body and began to crawl. eventually it’s leg gets scraped off)
Theory of Use and Disuse
- Traits that are used: remains strong
- Traits that are not often used (disused): Weakens and disappears over time
Theory of passing on acquired traits
- That traits acquired during its lifetime can be passed on it’s offspring (Lamarck’s theory is very old, this is untrue)
One of the theories of evolution, Darwin’s theory explain that evolution occurs in five steps (not theories) which are..
Overproduction Struggle for existence variation survival of the fittest (natural selection) origin of new species
in the first step of evolution (Darwin’s theory), overproduction is when..
the number of offspring produced by a species is more than how much it can survive (Due to the environment and offsprings all being unique, only some will survive leaving the ones fitted for the environment)
In the second step of evolution (Darwin’s theory), struggle for existence means that..
every organism faces a struggle to survive (A fraction of the offspring will survive due to fierce competition for food, shelter, etc)
In the third step of evolution (Darwin’s theory), variation is..
Even though individuals of the same species are considered same within their species, they some what different from each other (physically)
Only identical twins are considered same
In the forth step of evolution (Darwin’s theory), survival of the fittest is..
nature selecting which organisms will survive based on the traits that give them an advantage in the environment
in the fifth step of evolution (Darwin’s theory), Origin of new species is..
organisms that survive, pass on they’re traits to their offspring. This eventually lead to speciation
What is speciation?
a new kind of plant or animal being created
