Module 1 - Diversity Flashcards
(52 cards)
1
Q
Levels of diversity
A
genetic, species, ecosystem
2
Q
Biological organisation
A
cell –> tissues —> organ –> organ system –> organism –> species –> population –> community –> ecosystem –> biosphere
3
Q
Hybridization
A
when two species interbreed - unlikely due to ecological + behavioral isolation
4
Q
Genotype
A
genetic makeup of organism
5
Q
Phenotype
A
observable characteristics
6
Q
Taxonomy
A
classification of organisms
7
Q
Species classification
A
Kingdom, Phylum, Class, Order, Family, Genus, Species
8
Q
Within-species diversity
A
- sexual dimorphism = differences in appearance between sexes due to sexual selection
- mimicry = species that resembles toxic species as result of natural selection
- hermaphrodites = social hierarchy sex determination - switch sex for dominance
9
Q
Cryptic species diversity definition
A
species that show morphological similarities but aren’t genetically in same group
10
Q
Cryptic species case study - Blue Mussels
A
- variation in shell morphology
- bioindicator for water quality
- shell shape used to see effect of salinity levels + water quality
- variance in shells due to different water qualities
- enable species decline to go unnoticed as look similar
- native mussel disappeared, risk of inaccurate data recordings of water quality if wrong species
11
Q
Food webs
A
used to visualize species connectedness, energy flow + functional relationships
12
Q
Autotrophs
A
use inorganic materials to synthesize organic compounds e.g. plants, algae
13
Q
Heterotrophs
A
acquire energy by breaking down organic compounds made by other organisms e.g. animals, fungi
14
Q
Trophic level order
A
Primary producers –> Herbivores –> Primary carnivores –> Secondary carnivores
+ detritivores
15
Q
Energy transfer through trophic interactions
A
- number of trophic levels determined by energy available
- 10% energy loss at each level
- longer food chains in ocean as more biomass
- fewer apex predators as high energy requirement but little energy available at top trophic level
16
Q
Foodweb interactions
A
- direct + indirect effects
- big, fierce animals = keystone species as exert top down predation pressures
- changes in population B due to predator (direct) affect competition between A and B (indirect)
- big, fierce animals more likely to go extinct –> less energy available
17
Q
Population
A
all individuals of a given species that live and reproduce in particular place + time
18
Q
Community
A
local populations of multiple species that interact with one another
19
Q
Factors that determine distribution of species
A
- atmospheric variables e.g. temp, rainfall
- biogeochemical variables e.g. nutrients, trophic pathways
- population dynamics e.g. feeding, breeding
- human impacts e.g. pollution, hunting
20
Q
Niche
A
ways an organism uses resources of its environment and its ecological role in the habitat
21
Q
Rocky shore zonation
A
- different patterns of distribution based on wave action and tidal zones –> different niches
- lower shore = kelp, mid shore = barnacles + wracks, upper shore = porphyra
- experimental removal of cophyllum from mid shore in Isle of Man UK
- Fucus serratus from lower shore extends further up shore
=> zonation due to both competition and physiological tolerances
22
Q
Competitive exclusion principle
A
two species with identical requirements cannot co-exist, one will outcompete the other
23
Q
Competition for space among barnacles
A
- coexist in same rocky areas of shore
- semibalanus removed + increase in Cthalamus
- interference competition –> range of species restricted by competition
24
Q
Fundamental niche
A
habitat species capable of using based on physiological needs
25
Realised niche
actual conditions under which species is found, incorporates ecological factors such as competition
26
Top-down control case study w/ starfish + killer whales
- predator removal experiment with starfish
- mussel = dominant competitor
- starfish - generalist predator
- removal reduced community diversity as mussels dominated community
- complete change in food web structure = trophic cascade
- top-down effect of orcas switching to otter prey --> otter population small = sea urchins abundant + can control kelp density
- distribution changes in predator presence
27
Keystone species
Species with a disproportionately large impact on the community
28
Trophic cascades
processes at upper trophic levels flow down to two or more lower levels --> top-down control
29
Functional diversity
- function organism performs in community
- certain traits in abundance make certain organisms critical
- predict ecosystem processes more accurately than species richness
30
Evolutionary argument
- evidence of intelligent design due to complex functionality of organisms
- random mutations due to selection results in complex design with advantages and disadvantages
- Darwin created framework to explain biological complexity
31
Evolution
descent with modification
32
Natural selection
differential survival and reproduction of individuals due to differences in phenotypes
33
Steps in natural selection
1. variation - individuals in population vary in traits
2. differential fitness - traits that increase chances of survival/reproduction
3. inheritance - traits passed from parents to offspring
4. - adaptation - over generations, advantageous traits more common
34
Case study - Peppered moths
- 1900s dominant form = white moths due to lichens on trees
- IR caused trees to become sooty, shift in dominant species to black moths as advantageous trait
- clean air act = shift back to white moths
- phenotypic traits track environment and quickly respond when selection pressure strong
35
Case study - Darwin's Finches
- variation in beak shape due to difference in food availability, traits radiated
- drought - small, soft seeds unavailable --> rapid shift in size of beak, large beaks survived
- flooding - small seeds abundant, large beaks disadvantaged
36
Case study - Trinidadian guppies
- waterfall barrier between upstream and downstream guppies
- upstream male guppies colorful as relaxed predators so could put more energy into reproductive behaviors
- downstream male guppies drab as high predation
- experiment: downstream guppies placed in upstream area, became more colorful --> males evolve to become more conspicuous when predation relaxed
- evolutionary change occurred in just over 4 years --> microevolution
37
Timeline of life on Earth
- Hadean - volatile Earth, fiery
- Archean
- Proterozoic
- Phanerozoic
38
Hadean timeline
3800-4600 MYA
39
Archean timeline
2500-3800 MYA
40
Proterozoic timeline
500-2500 MYA
41
Phanerozoic timeline
present-500 MYA
42
Archean events
- first life emerged - prokaryotes
- prokaryotes evolved from protocells --> single-celled, no organelles
- cyanobacteria = only photosynthetic prokaryote, important for evolution as produced oxygen --> changed atmosphere, allowing evolution of eukaryotes
- early life = stromalites + thrombolites
43
Theories on how life began
1. extra-terrestrial origin - meteorites containing amino acids
2. natural processes - random events of molecules forming from water, electric charge etc. in deep sea hydrothermal vents, formed protocells
44
Proterozoic events
- early life
-rise of eukaryotes after emergence of cyanobacteria + increase in oxygen
- eukaryotes = 1500 MYA, single or multi-celled, nucleus with DNA, organelles, membrane
- endosymbiosis - ancestral eukaryote engulfs bacteria to form mitochondria/chloroplast
45
Phanerozoic era
- recent
- explosion of life
- Cambrian explosion
- first land plants which caused development of food chains
- tetrapod evolution - fleshy-finned fish which could survive on land
- radiation into mammals and reptiles
- resulted in appearance of marsupial mammals, birds + flowering plants
46
Cambrian explosion
- evolutionary burst
- 540 MYA
- marine animals evolved into all major modern body plans
- mass evolutionary diversification - appearance of earliest arthropods, molluscs, echinoderms + chordates, bilateral symmetry, evolution of eyes
- nutrients from erosion increased food web complexity
- all current animals originated in Cambrian era
47
Permian-Triassic Extinction (great dying)
- 250 MYA
- 90% marine species lost + 70% terrestrial vertebrates
- increased CO2 in atmosphere
48
Cretaceous-Tertiary Extinction (K-T)
- 65 MYA
- asteroid hits Gulf of Mexico
- 75% plants + animals lost
- all tetrapods over 25kg extinct
- only line of archosaurs to survive = modern birds + crocs
49
Other extinction causes
- periods of glacial events and heating
50
Geological history
- changes in structure + formation of continents
- break up of Rodinia, formation of Gondwanaland, formation of Pangea, break up of Pangea
- tectonic plates explain patterns of distributions of different life forms --> geographic isolation
51
Evolution of mammals following break up of Pangea
- 300 MYA = birds + reptiles
- 145 MYA = marsupials
- split off to form placental mammals
- migration of marsupials in Late cretaceous to Australia + extinctions in North America as began to radiate out
52
Human evolution
- last 10 million years, evolution of hominids
- homo common ancestor = Australopithecus africanus (Lucy)
- homo evolved 2 MYA
- homo sapiens evolved 300 000 YA
