exam revision

Question 1

what is biodiversity

Answer 1

biodiversity refers to the immense variety of genes, ecosystems and species on earth

Question 2

what is the difference between species diversity and genetic diversity

Answer 2

the difference between species diversity and genetic diversity is that species diversity refers to the variety of species within an ecosystem whereas genetic diversity is the range of genetic traits of a species

Question 3

how does significant biodiversity within a species result in the evolution of the species over time after an environmental change occurs

Answer 3

if there is sufficient biodiversity when an environmental change occurs some variations may be adapted to the changing environment. these variations will survive while natural selection, selects the poorly adapted variations for extinction. thus biodiversity will lead to a change in the population.

Question 4

what is a selection pressure

Answer 4

selection pressures are external agents that affect an organisms chance of survival depending on its genotype (genetic variations)

Question 5

difference between biotic and abiotic selection pressures

Answer 5

the difference between biotic and abiotic selection pressures is that biotic selection pressures refer to living selection pressures (predators, disease and climate change) whereas abiotic is non-living such as light, wind and soil

Question 6

what is natural selection, provide an example

Answer 6

natural selection is the influence of environmental factors which decide whether a species will survive and reproduce (survival of the fittest). an example of this would be black and tan coloured mice. the black mice have the ability to blend in with the soil so they dont get eaten by predators whereas the tan coloured mice can be easily seen which doesn’t favour them as the predator will eat them thus causing the tan coloured mice to be decreased in variation and population. the black mice have the favourable genotype/phenotype so they don’t get eaten.

Question 7

what will likely happen to 2 different populations of a species if they are geographically isolated for a long period of time

Answer 7

speciation will occur to that population. speciation is the process by which new types of species are thought to develop from nalready existing ones by evolution. the process of speciation includes a population being divided by a geographical barrier seperating the population in 2.

Question 8

how does evolution rely on natural selection

Answer 8

evolution relies on natural selection because natural selection is a mechanism for evolution. this causes the process of speciation leading to biodiversity and evolution

Question 9

difference between natural and artificial selection

Answer 9

natural selection refers to the influence of environmental factors which decide whether a species will survive and reproduce (survival of the fittest) whereas artificial selection is the intentional breeding of plants and animals to produce desirable traits

Question 10

what are the different sources for evidence of evolution

Answer 10

palaeontology, embryology, biochemistry, molecular biology, biogeography

Question 11

difference between analogous, homologous and vestigial structures

Answer 11

analogous structures are structures that have similar features but have evolved differently whereas homologous structures are structures that have similar structures/features because they have evolved from the same ancestor. vestigial structures however are part of an animal that is significantly reduced in size or lacks functionality compared to the animal’s ancestors

Question 12

what is genetic drift

Answer 12

genetic drift is the process by which the genetic information in a population changes at random

Question 13

what is gene flow

Answer 13

gene flow refers to the movement of genetic material from one population to another

Question 14

what is mutation

Answer 14

mutation is the spontaneous or induced change in the gene sequence of an organism’s dna

Question 15

define evolution

Answer 15

evolution refers to the genetic changes that occur within a population over a long period of time

Question 16

define variation

Answer 16

the genetic differences within a population

Question 17

what is speciation

Answer 17

speciation is the process by which new types of species are thought to develop from already existing ones by evolution

Question 18

how have previous events impacted global diversity

Answer 18

previous events that have impacted global diversity are volcanic activity and climate change. these events have led to the mass extinction of species that affect global diversity because it has resulted in a large loss of genetic variation

Question 19

what is mutation in evolution

Answer 19

for evolution to occur there must be a mutation of at least 1 species

Question 20

example of how gene flow can occur

Answer 20

by natural disasters

Question 21

define adaptation and provide an example

Answer 21

adaptations are characteristics that contribute to a species’ suitability for an environment. an example would be giraffes with long necks

Question 22

example of a homologous structure

Answer 22

the wings of bats and birds

Question 23

example of an analogous structure

Answer 23

the fins of a fish, penguin and dolphin

Question 24

example of an indirect fossil evidence

Answer 24

footprints

Question 25

what are the conditions needed for speciation

Answer 25

geographical isolation, selection pressure and reproductive isolation

Question 26

what are 4 human activities that have negatively impacted biodiversity and can lead to the extinction of plants and animals

Answer 26

deforestation, polluting the environment, overfishing and hunting animals for food

Question 27

what is the criteria that must be met for a species to be considered endangered

Answer 27

when a large decrease of the population of at least 70% has occurred over the past decade or when less than 250 mature individuals are existing within a population

Question 28

example for artificial selection

Answer 28

selective breeding of dogs

Question 29

example of a vestigial structure

Answer 29

coccyx of humans

Question 30

define half-life

Answer 30

the time taken for the radioactivity of a radioactive substance to be reduced in half

Question 31

what is absolute dating

Answer 31

determining the actual age of a material

Question 32

what is relative dating

Answer 32

relative dating is determining the order of past events without specific age

Question 33

what can the process of natural selection not occur without

Answer 33

predators

Question 34

what is the natural selection process

Answer 34

1. variation naturally exists in the population due to processes such as sexual reproduction, crossing over, gene flow and mutations
2. the genetic information of some of the organisms in the population is expressed in favourable traits
3. individuals with favourable traits are more likely to survive and reproduce than others of the same species
4. over time the individuals with the favourable traits become more numerous in the population