4.3 Classification & Evolution Flashcards

Question

Which 2 factors cause variation

Answer 1

Genetic Environmental

Answer 2

1. Alleles 2. Meiosis 3. Mutations 4. Chance 5. sexual Reproduction

Answer 3

Genes have alternative forms. This means there will be alternative versions of characteristics depending on the alternative allele

Answer 4

Changes in DNA sequence leas to change in the protein it codes for and if a protein changes, then the physical and metabolic characteristics might change too. This change can also be passed on to the offspring if mutation occurs in gamete which can lead to further variation down the line

Answer 5

During meiosis, before the nucleus divides and the chromatids of a chromosome separate, the genetic material inherited from the two parents is mixed up by independent. Assortment and crossing over. This leads to the gametes of an individual showing variation.

Answer 6

The offspring produced from 2 individuals inherit alleles from each of the parents. Everyone produced therefore differs from the parent.

Answer 7

Many different gametes are produced from the parental genome during sexual reproduction. It is a result of chance as to which to combine. The individuals produced therefore also differ from their siblings as each contains a unique combination of genetic material.

Answer 8

A characteristic where the value can take any value

Answer 9

a characteristic that can only result in certain values

Answer 10

When continuous variation data is plotted on graph, they usually result in production of a bell-shaped curve known as normal & the characteristics include: 1) The mean, mode and median are the same 2) Has Bell shape which is symmetrical about the mean 3) 50% of values are less than mean & 50% of values are greater than mean 4) Most values lie close to mean value – The number of individuals at the extreme ends are low

Answer 11

Is a measure of how spread out the data is The greater the SD the greater the spread of data / variation of data values 68% of values lie within 1 standard deviation of the mean 95% of values lie within 2 SD of the mean 99.7% of values are within 3 standard deviations of the mean Smaller the SD the more tightly clustered the values are around the mean and less variation in data

Answer 12

Used to compare the mean values of 2 sets of data Data must be normally distributed There must be enough data to make the calculation reliable Different sample sizes may be used

Answer 13

This is used to consider the relationship between 2 sets of data

Answer 14

A characteristic that increase an organism's chance of survival and reproduction in its environment.

Answer 15

Adaptation of physical features.

Answer 16

Camouflage Body covering e.g. spikes & hairs to protect. Teeth, EG different shapes for different diets. Mimicry to copy another animal's appearance or sound fool predator

Answer 17

Marram Grass (xerophyte plant) has adapted to reduce the rate of transpiration

Answer 18

curled needs to minimise surface area exposed. Hairs to trap moist air. Sunken Stomata to less lightly open them. Thick waxy cuticle to reduce water loss via evaporation.

Answer 19

Adaptation in way that an organism act which are learnt through observation or parents

Answer 20

Courtship – Many animals exhibit elaborate courtship behaviours to attract a mate to increase chance of reproducing Seasonal behaviours – enable organism to cope with change in their environment e.g. Migration & hibernation

Answer 21

Adaptation which takes place inside organism

Answer 22

Water holding - Frogs storing water inside the body to survive a long time without water. Antibiotic production - Some bacteria produce antibiotics to kill other species of bacteria. Poison production - Reptiles produce venom to kill their prey, or plants have poison on their leaves

Answer 23

When unrelated species have similar anatomical features. This occurs because they are exposed to similar selection pressures & environments

Answer 24

Marsupials & Placental mice: are both small & agile climbers that live in dense ground and forage in the night for small food items. They are also similar in size & body. Flying Phalangers & flying squirrels: Both are gliders that eat insects and plants. Their skin is stretched between their forelimbs and hind limbs to provide a large surface area from gliding from one tree to the next. Marsupia & Placental Moles: Both borrow through soft soil to find worms and grubs. They have a streamlined body shape and modified forelimbs for digging. They also have velvety fair which allow smooth movement through the soil. They differ in fur colour as the marsupial mole ranges in colour from white to orange, whereas the placental mole is grey

Answer 25

Structures that perform a similar function but are not similar in origin.

Answer 26

structures which are similar in origin but not in function.

Answer 27

Organisms in a species have variation in their characteristic caused by differences in genes. Organisms are exposed to an environment at a selection pressure. Those who are well adapted to the pressure survive and reproduce. Organisms who reproduced pass on the advantageous allele or characteristic. Over generations and reproductive success, the advantageous allele coding for advantageous characteristic which causes the characteristic then increases in frequency. Over a long period of time and many generations, the process can lead to the evolution of a new species.