Lecture 33: Principles of evolution

Question 1

Adaptive changes in organisms occur through natural selection, what can this lead to?

Answer 1

the formation of new species

Question 2

How do organisms evolve?

Answer 2

• response to environmental change creating new niche
• occupying unoccupied niche
• migrating to new environment

Question 3

humans shared a common ancestor with chimpanzees, how many years ago?

Answer 3

eight million years ago

Question 4

humans shared a common ancestor with whales, how many years ago?

Answer 4

60 million years ago

Question 5

All organisms are related far back in time to probably a single successful, DNA containing cell, true or false?

Answer 5

true

Question 6

How do changes in species occure?

Answer 6

natural selection

Question 7

what do variations involve?

Answer 7

body size, hair colour, facial markings, voice properties, or number of offspring

Question 8

what traits show little or no variation?

Answer 8

number of eyes in vertebrates

Question 9

what does the case of the pepper moth show us?

Answer 9

natural selection changing the frequency of a particular allele or gene.

Question 10

what happened to the white pepper moth?

Answer 10

industrial pollution made trees darker, caused increase in black pepper moth, population chawed due to environmental change.

Question 11

can taits be influenced by environmental conditions?

Answer 11

yes

Question 12

what happens if theres a high rate of population growth?

Answer 12

local resources can’t support them all leading to a struggle for resource

Question 13

Individuals who possess traits that are well suited for the struggle for resources will do what?

Answer 13

They will reproduce, contributing more offspring to the next generation.

Question 14

Do certain characteristics lead to individuals being eliminated?

Answer 14

yes

Question 15

what are the first 5 principles of evolution?

Answer 15

1. Variating exists, through random mutations and recombination
2. Evolutionary changes depend upon changes within populations. (proportion of genotypes)
3. Allele frequencies remain constant unless forces change them.
4. Natural selection can alter allele frequency.
   5, Evolution proceeds at afferent rates

Question 16

what factors alter allele frequency in a population?

Answer 16

mutation, genetic drift and gene flow

Question 17

what is a mutation?

Answer 17

change in DNA, the genetic material

Question 18

what does an organisms DNA affect?

Answer 18

looks, how it behaves, and its physiology

Question 19

Are mutations random?

Answer 19

yes

Question 20

Do all mutations matter to evolution?

Answer 20

Not all mutations matter to evolution

Question 21

what is a point mutation?

Answer 21

a mutation affecting only one or very few nucleotides in a gene sequence.

Question 22

what can point mutations cause?

Answer 22

These can cause miscoding that can result in changes to a protein or even its absence

Question 23

what are examples of biological mutagens?

Answer 23

certain chemicals present in bacteria, plants and animals

Question 24

what are examples of non-biological mutagens?

Answer 24

heavy metals, radiation, cooked food

Question 25

what does the advantage of an allele or genotype depend upon ?

Answer 25

the enviroment

Question 26

what does expiation general require?

Answer 26

barriers to gene flow

Question 27

what are the principles of evolution, 6-10?

Answer 27

6) Mutations are advantageous in some ways and disadvantageous in others, or neutral. The advantage depends upon the environment.
7) The chance that a mutation will occur is not affected by the advantage or disadvantage it confers.
8) Organisms cannot evolve adaptations in anticipation of future events
9) Not all characteristics evolved because they were adaptive.
10) Speciation generally requires barriers to gene flow

Question 28

what are the principles of evolution, 11-15?

Answer 28

11) If gene flow among local populations of a species is sufficiently restricted, the populations may so diverge that they will not or cannot interbreed. That is, speciation occurs.
12) If two populations have become different species, the genetic changes in one are usually not transmitted to the other.
13) The principles of intraspecific evolution apply to all genetically controlled characters.
14) Biodiversity can be defined in terms of genetic diversity, species diversity and ecosystem diversity.
15) Systematics is the study of biodiversity and the evolutionary relationships that exist among organisms.

Question 29

Does evolution through natural selection always allow organisms to better survive?

Answer 29

No, it can can result in extinction as species fail to adapt to new conditions.

Question 30

whats an Adaptive significance off the complex nervous system?

Answer 30

. increases behavioural repertoire – more able to cope with environmental pressures
. Animals to respond in more diverse ways to environmental conditions

Question 31

what responsiveness do bacteria and plants show?

Answer 31

phototaxis (light)
chemotaxis (chemicals)
geotaxis (gravity)

Question 32

How does a ciliate swim smoothly?

Answer 32

coordinated beating of its cilia controlled by electrical potentials

Question 33

what fibres are associated with the sensory nervous system?

Answer 33

afferent fibres

Question 34

what fibres are associated with the motor system?

Answer 34

efferent fibres

Question 35

What helps us understand how the nervous system may have evolved?

Answer 35

Diverse range of living invertebrates offers clues to how the nervous system might have evolved

Question 36

what is evolution?

Answer 36

a random process leading to changes in species, driven by variations and mutation.