PART 2 - Mechanisms of population change

Question 1

Variation is..

Answer 1

the differences that may be observed in an organism

There are visible (example: color) differences and invisible (example: Biochemical) differences.

Question 2

Variation can occur between different species, this is called..

Answer 2

InTERspecific variation

Question 3

Variation can also occur within the same species, this is called..

Answer 3

inTRAspecific variation

Question 4

There many species on earth, majority of them are plants, insects and microorganisms. How many different species are there on earth?

Answer 4

8.7 million different species

Nearly 10,000 new species are discovered every year

Question 5

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..

Answer 5

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)

Question 6

What is adaptation?

Answer 6

Change or the process of change (change to suit the environment)

Question 7

There are 3 types of adaptation, list them..

Answer 7

Structural, behavioural and physiological

Question 8

One of the 3 types of adaptation, structural adaptation is..

Answer 8

the physical features of an organism (such as the beak of a bird or the fur of a bear)

Question 9

One of the 3 types of adaptation, behavioural adaptation is..

Answer 9

the behaviour of organism to the environment (example: a cat hissing when threatened)

Question 10

One of the 3 types of adaptation, physiological adaptation is..

Answer 10

A response to the environment from an individual external stimulus in order to maintain homeostasis (example: shivering when cold)

Question 11

The variation within species results from..

Answer 11

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

Question 12

What causes variation to arise? (genetic changes and recombination)

Answer 12

Mutation and it continuously happen in the DNA

Question 13

What are some of the results of mutation? (list 4)

Answer 13

Exhibition (display) of new characteristics, death of cells, malfunctioning cells, multiplying of more cells with mutation (this results in a tumour).

Question 14

Mutations does not only occur when organism are developing, they also occur a..

Answer 14

after birth. Mutation occurs to fit the environment.

Question 15

After birth, mutation can still occur within the organism, where does it occur and what is their names? (there is 2)

Answer 15

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

Question 16

What is natural selection?

Answer 16

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

Question 17

What is malaria?

Answer 17

a illness that cause death

Question 18

When malaria was present in Africa, how did this illness get spread?

Answer 18

Mosquitoes carry blood that contains illness and infect a person when it bites

Question 19

What does an individual need to be immune to malaria?

Answer 19

Sickle cell anemia

Today, Africa now contains most individual with sickle cell anemia. This is natural selection at work

Question 20

What is the process of evolution?

Answer 20

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

Question 21

What is the cause of evolution?

Answer 21

natural selection within an environment

Question 22

What are the two theories of evolution?

Answer 22

Lamarck’s theories and Darwin’s theory

Question 23

One of the theories of evolution, Lamarck’s theories consists of 3 theories which are..

Answer 23

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)

Question 24

One of the theories of evolution, Darwin’s theory explain that evolution occurs in five steps (not theories) which are..

Answer 24

Overproduction
Struggle for existence
variation
survival of the fittest (natural selection)
origin of new species

Question 25

in the first step of evolution (Darwin’s theory), overproduction is when..

Answer 25

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)

Question 26

In the second step of evolution (Darwin’s theory), struggle for existence means that..

Answer 26

every organism faces a struggle to survive (A fraction of the offspring will survive due to fierce competition for food, shelter, etc)

Question 27

In the third step of evolution (Darwin’s theory), variation is..

Answer 27

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

Question 28

In the forth step of evolution (Darwin’s theory), survival of the fittest is..

Answer 28

nature selecting which organisms will survive based on the traits that give them an advantage in the environment

Question 29

in the fifth step of evolution (Darwin’s theory), Origin of new species is..

Answer 29

organisms that survive, pass on they’re traits to their offspring. This eventually lead to speciation

Question 30

What is speciation?

Answer 30

a new kind of plant or animal being created