Life and Diversity

Question 1

species

Answer 1

organisms that are reproductively isolated from other species and are able to interbreed to produce fertile offspring

Question 2

issues with the species definition

Answer 2

does not consider asexual organisms
does not extend to extinct species
ring species are reproductively isolated but not genetically species
hybridisation (common in plants) - genetically and morphologically distinct oaks can hybridise, producing fertile offspring where populations overlap

Question 3

morphospecies concept

Answer 3

members of a species look morphologically alike. does not consider sexual dimorphism or that young look different to adults

Question 4

ecological species concept

Answer 4

determining a species based on its niche, that is, the set of resources that it uses in its environment. useful for classifying asexual bacteria

Question 5

phylogenetic species concept

Answer 5

individuals of a species share common ancestry and a common fate

• morphological and genetic traits
• avoids reproductive isolation which is useful for fossils and bacteria
• boarders between taxa are not always clear cut

Question 6

biodiversity

Answer 6

the number of species present in the biosphere or the relative abundance of species

Question 7

cichlids and biodiversity

Answer 7

hundreds of species with specialisations to specialised habitats - food types
product of adaptive radiation: rapid branching through speciation of a phylogenetic clade into closely related species
introduced Nile perch drove many to extinction and decreased water quality and increased fishing helped
decreased biodiversity

Question 8

extinction

Answer 8

a process of macroevolution 
1/1 million species go extinct a year 
5 mass extinctions 
humans: destroy habitat, introduce species and over harvest 
10-50% lost in next century

Question 9

genetic diversity

Answer 9

genetic variation within a species and their future potential to adapt. can be measured as chemical diversity - chemicals produced

Question 10

ecosystem diversity

Answer 10

number of different ecosystems on the planet or within an area
- whole ecosystems can be lost

Question 11

current species diversity

Answer 11

named 1.5 million eukaryotes (probably 8.7 mill)

Question 12

patterns in biodiversity

Answer 12

• not evenly distributed
• endemic species: only found in one place and vulnerable to extinction
• latitude: warmer areas at the equator are not affected by the last glaciation. this may increase heterogeneity or the number of ecological niches. these ares are more stable (less seasons), even day length, can specialise with less risk and day and night niches are more even
• age of places (more time to speciate)
• more biodiversity and endemism in the tropics (40% of earth)

Question 13

conservation of biodiversity

Answer 13

biodiversity hotspot: areas with large numbers of endemic species and therefore at risk
1500 or more endemic plant species and 70% of area disturbed by humans
34 hot spots

Question 14

importance of biodiversity to human health

Answer 14

secondary plant compounds (toxins that protect plants) are medicine
antibiotics from bacteria and fungi
animal venoms and poisons are researched medically

Question 15

agricultural diversity

Answer 15

breeding and selecting crops for 10 000 years to create varieties for demand, growing conditions and disease resistance
biodiversity is important!

Question 16

potato famine

Answer 16

from low crop diversity

disease resistance is increased by biodiversity

Question 17

wild forms

Answer 17

allow for introduction of gene variety. come from seed banks

Question 18

quality of soil

Answer 18

chemicals are detrimental
organisms in soil maintain nutrient cycles - break down matter, affect soil texture which changes water and oxygen dynamics

Question 19

ecosystem services

Answer 19

metabolic activities of organisms

pollination is an example

Question 20

pests

Answer 20

pesticides are expensive and pests adapt
kill non pests and harm humans
introduce predators and parasites can help
increase landscape diversity of pest enemies - must protect diversity

Question 21

wild food sources

Answer 21

fishing - not sustainable, drastic decrease, fished species become a minor component
loss of money and food source

Question 22

psychological and moral value

Answer 22

humans have adapted to live in a natural environment and have cultural, spiritual and recreational value
city is a stressor
moral responsibility not to cause damage

Question 23

how many species?

Answer 23

5.3 million to 1 trillion

Question 24

why is it hard to count number of species?

Answer 24

inaccessible so must estimate based on patterns

very small or hard to classify (like bacteria)