Biology Notes - module 3 PDF

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just summary notes of module 3...

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NOTES – MODULE 3 TOPIC 7 – EFFECT OF THE ENVIRONMENT ON ORGANISMS SELECTION PRESSURES Inquiry question: how do environmental pressures promote a change in a species diversity and abundance? Ecosystems: combination of all abiotic and biotic factors and their interactions. Selection pressures: driver of natural selection, external agents that impact an organisms ability to survive. Abiotic - Soil Ph - Soil Salinity - Temperature - Humidity - Water pH - Water Salinity - Light

Biotic -

Predation Competition for resources Food availability Disease Parasites Available mates

CANE TOADS -

Introduced species to Australia to control sugar cane beetles Invasive species due to lack of natural predators and mass production of spawn Is capable of adapting in most environments Toxic to all other organisms, eggs are also toxic Some species have adapted to no longer eating toads, others have become tolerant to toxins

PRICKLEY PEAR -

Introduced to begin dye industry Fast spreading, most money was spent on clearing it out Controlling the population through cactoblastis moth that ate the plant (biological control)

TOPIC 8 - ADAPTATIONS Inquiry question: how do adaptations increase the organism’s ability to survive? Adaptation: a characteristic an organism has inherited to better suit it to its environment -

Structural: how an organism is built, shape or size of features. E.g., eucalyptus leaves have thin waxy leaves that minimise water loss enable gas exchange Behavioural: how an organism behaves. Red kangaroos lick their legs to cool down

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Physiological: how an organism function. E.g., salt bush grows in hot conditions that allow its salt to grow and reflect light

NATURAL SELECTION Some organisms have adaptations that better suit them to their environment than others. These organisms are more likely to survive and give birth to offspring. Darwin’s survival of the fittest: 1. 2. 3. 4.

Variation within a populations More offspring are produced than can survive Better adapted will continue living and making offspring Good adaptations keep being alive and increase in a populations

TOPIC 9 - THEORY OF EVOLUTIONS THROUGH NATURAL SELECTION Inquiry Question: What is the relationship between evolution and biodiversity? Biodiversity: diversity of life on earth. -

Diversity is increased through genetic change and evolutionary process Reduced by habitat destruction, population decline and extinction

Divergent evolution: -

Similarities due to a common ancestor Species from a common ancestor have separated and evolved differently better suit their environment E.g: Darwin’s finches

Convergent evolution: -

Similarities between unrelated organisms Similarities due to common environments/needs E.g: sharks and dolphins

Punctuated equilibrium: Evolution caused in short rapid bursts of change followed by long periods of stability Gradualism: natural selection changes features within a species which slowly is passed on until only the new species lives

TOPIC 10 - EVIDENCE OF EVOLUTION Evidence: -

Biochemical: the study of chemicals found in cells, molecular biology and genetics. More similar proteins and DNA shows more closely related organisms Comparative anatomy: the study of similarities and differences in the structure of living organisms.

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Comparative embryology: comparing the developmental stages of different species. Predict that closely related species show similarities in their embryonic development Biogeography: study of the distribution of living things over Earth. Provides evidence that species have originated from common ancestors and when isolated, have evolved into new species Palaeontology / dating fossils: Sequence of fossils found in rock formations should reflect the order of changes observed in organisms that originated from a common ancestor. o Dating: provide evidence of the sequence of geological events but not the exact dates of an event. o Absolute dating techniques (radiometric dating) provide evidence of the actual dates of geological events and the age of fossils...