360 Science / B1a.01 Environment lesson notes

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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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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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

360 Science / B1a.01 Environment lesson notes

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