end of year exam Flashcards
define biodiversity
biodiversity refers to the variety of life that exists, the genetic material they posses and the ecosystems the inhabit.
what 2 factors make up an ecosystem
abiotic and biotic
name 5 abiotic factors
- climate
- sunlight
- humidity
- shelter
- pollutants
name 5 biotic factors
- humans
- plants
- bacteria
- disease
- predation
name the 5 measures of species
- simpsons diversity index
- species richness
- relative species abundance
- percentage cover
- percentage frequency
define species richness
number of different species in an ecosystem
define relative species abundance
how common/uncommon or even/uneven a species is relative to its surroundings
e.g.
gum trees = abundant in Australia
zebras = not abundant in Australia
define percentage frequency
how often species occurs when a sample of the environment is taken
% frequency = no. of quadrats species found / total no. quadrats
define percentage cover
estimate of what percentage of an enclosed area quadrat is occupied by each species
define simpsons diversity index
defines how diverse an ecosystem
SDI= 1- (organisms of one species multiplied by (organisms of one species - 1) / organisms of all species multiplied by (organisms of all species - 1))
how to use predation to compare ecosystems
compare rates of predation
how to use competition to compare ecosystems
compare resources and strain
how to use symbiosis to compare ecosystems
relationships where at least one benefits
how to use disease to compare ecosystems
compare rates of transmission
how to use substrate to compare ecosystems
surface/substance where organisms live. analysing substrate provides information about nutrients and composition of enviroment
what is biological classification based on
different levels of similarity of physical features, methods of reproduction and molecular sequences.
define morphologies
shape/structure of an animal. used to categorise animals.
define taxonomy
organising organisms is called taxonomy and the groups are called taxonomic groups
define species
organisms that can be interbreed under natural conditions while producing fertile, viable offspring
describe the Linnaean system
the Linnaean system categorises organisms based on their physical features. their are 5 kingdoms that organisms can be grouped into.
- animals
- plants
- fungi
- monera
- protists
how are animals classified in the Linnaean system?
multicellular, capable of movement, internal digestion and heterotrophic
how are plants classified in the Linnaean system?
plants: photosythetic, autotrophic and multicellular
how are fungi classified in Linnaean system?
not capable of movement, usually multicellular and heterotrophic, external digestion
how are monera classified in the Linnaean system?
unitcellular prokaryotes
how are protists classified in the Linnaean system?
mostly unicellular and eukaryotic
describe the method of reproduction. sexual and asexual
asexual: one parent, offspring identical to parent, quicker, low variation (only mutation can introduce variation)
sexual: two parents, offspring not identical, slower, high variation.
what are interspecific hybrids?
two different species breed and create new offspring that presents traits from each parent. offspring are often sterile and known as infertile hybrid species
give an example of an interspecific hybrid
Equus Mulus: mule
offspring of male donkey and female horse
mules can be male or female
they cannot reproduce as they inherit an odd amount of chromosomes donkey (62) and horse (64)
how does light get converted to chemical energy?
small proportion of solar energy is captured by plants -> transformed via photosynthesis into chemical energy -> chemical energy released from the bonds of glucose molecules and used for metabolisms when broken down during cellular respiration
how is biomass produced
solar energy is converted into biomass through the action of living things. autotrophs produce biomass
what is biomass
total mass of living matter
what are autotrophs?
photosynthetic organisms that capture the suns energy and produce their own organic compounds
what is a trophic level?
a level of the food chain of an ecosystem based on feeding relations e.g. procurers herbivores
what are heterotrophs?
organisms that need other organisms for food
what is the competitive exclusion principle?
the idea that two species cannot be competing for the same resource while stably coexisting as they will compete until one species wins while the other is forced into extinction or adaptation
what are keystone species?
species that influence their communities in a way that is not proportional to their abundance. they have a very big effect on the ecosystem even though they are a very small part of it
often predators
give an example of the flow on effects of a keystone species
- sea star prey of mussels
- without sea stars muscle population increases
- mussels eliminate other species form the community
define carrying capacity
the size of the population that can be supported indefinitely on the resources available in that ecosystem
calculate population growth rate and change
(birth + immigrants) - (deaths + emigrants)
calculate population size using Lincoln index
size of pop (N) = M x n / m
M = originally marked n = total number captured in second sample m= total number of recaptured in second sample
describe J-Curve
exponential boom and bust:
population has unrestricted growth before they are above the carrying capacity or another factor (climate migration) dramatically reduces the population
describe S-Curve
logistical growth:
change in population density of an organisms where it initially increases slowly and then rapidly as it approaches an exponential growth rate. it decreases and levels off as the carrying capacity of the environment is reached
define succsession
change in species composition when one community replaces another as a result of changing abiotic conditions by the previous species
define ecological succession
process of gradual evolution of an ecosystem
what are the 2 types of ecological succession?
primary and secondary
describe primary succession
catastrophic event (volcanic eruption, tsunami) cause the development of bare sits
describe secondary succession
caused by fires, still rich soil left. environment is not bare
what is a pioneer species
brings back life to the environment
define clades
organisms related by descent from a common ancestor
Identify the features of a pioneer species
- ability to fix nitrogen
- tolerance to extreme conditions
- rapid germination of seeds
- ability to photosynthesise
describe DNA
deoxyribonucleic acid is a double stranded molecule that occurs born d to proteins (histones) in chromosomes in the nucleus.
recall the structure of DNA including nucleotide composition
- sugar
- phosphate
- nitrogenous bases
recall the structure of DNA including complimentary base pairings
DNA guanine (G) always hydrogen bonds to cytosine (C) and adenine (A) to thymine (T) G C AT
recall the structure of DNA including weak hydrogen bonds
link bases on DNA strands
