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8/8/2019 360 Science / B1a.01 Environment lesson notes
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B1a.1
Environment
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B1a.1.1 Competition for resources
living things compete with each other for
resources
predators compete with each other forprey
animal populations are affected by
numbers ofpredators and competition for
resources
n1
n2
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Slide 2
n1 predator = animal that kills other animals for foodPaul Burgess, 10/24/2010
n2 population = total number of a species in a certian habitatPaul Burgess, 10/24/2010
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B1a.1.1 Competition for resources
This is a very simple model of
population change. Why?
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B1a.1.2 Sampling and estimating
populations real population changes are usually
complex because they involve many
variables need to sample populations, e.g. using
quadrants, to estimate sizes
computer models can make better
predictions than simple model if they take
many variable into account
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B1a.1.2 Sampling and estimating
populations
quadrant
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B1a.1.3 Our influence on the
environment economic, industrial and population
changes all effect the environment
desertication = loss of soil fertility deforestation can cause soil erosion
and increased flooding
n3
n4
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Slide 6
n3 deforestation = fellling trees and NOT replantingPaul Burgess, 10/24/2010
n4 soil erosion = washing away of soil
Paul Burgess, 10/24/2010
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B1a.1.4 Chains, webs and
pyramids food chains begin with green plants or
producers that make their own food by
photosynthesis
animals are
consumers that must
eat to get food
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B1a.1.4 Chains, webs and
pyramids each step in a food chain is called a
trophic level
energy is always lost from one trophiclevel to the next
populations often decrease along a foodchain [pyramid of numbers]
biomass always decreases along a foodchain because of the energy losses[pyramid of biomass]
n5
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Slide 8
n5 biomass = dry mass of living thingsPaul Burgess, 10/24/2010
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B1a.1.4 Chains, webs and
pyramids food chains usually link together to make
food webs
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B1a.1.5 Wheat versus meat
huge energy losses from wheat
[producer] to cow [consumer]
energy is lost for living [growth, movement,warming surrouding etc.]
huge amount of wheat to produce a small
amount of beef
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B1a.1.6 Going organic
farming uses fertilisers, pesticides and
other methods to increase production
some chemical used in farming canaccumulate in the environment
organic farming reduces the use of
artifical fertilisers and chemical peticides
or herbicides
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B1a.1.7 Changing organisms
humans have used selective breeding for
millenia to produce living things with
desired characteritics, e.g. cows with
higher milk yield, smaller dogs etc.
genetic modification is the transfer of
genes from one species to anothermore
precise than selective breeding andproduces immediate changes
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B1a.1.8 Natural selection
Natural selection
organisms over produce
there is variation amongst organims evenof the same species
organisms that are better suited to theirenvironment are more likely to survive
succesful parents may pass oncharacteristics to their offspring
species change oradapt
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B1a.1.8 Natural selection
Darwins theory ofevolutiongiven enough
time natural selection creates new species
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B1a.1.9 The evidence for evolution
Darwin looked to the fossils for evidenceof evolution
he did not know about genetics so did notunderstand how characteristics werepassed from parents to offspring
Darwins ideas were rejected by the
church and many people Darwins ideas remain controversial for
many
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B1a.1.10 Variation
to classify means to put into groups
there are so many different species that
we have to classify them to begin to studythem
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B1a.1.10 Variation
kingdom
phylum
class order
family
genus species