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Year 11 Biology - MODULE 3

The document discusses selection pressures, adaptations, biological diversity, and evidence that supports the theory of evolution by natural selection. Selection pressures include biotic and abiotic factors that can cause population change. Adaptations are structural, physiological, or behavioral traits that increase an organism's chance of survival. Biological diversity refers to genetic, species, and ecosystem variation. Comparative anatomy, embryology, and other evidence provide support for the theory of evolution.

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458 views5 pages

Year 11 Biology - MODULE 3

The document discusses selection pressures, adaptations, biological diversity, and evidence that supports the theory of evolution by natural selection. Selection pressures include biotic and abiotic factors that can cause population change. Adaptations are structural, physiological, or behavioral traits that increase an organism's chance of survival. Biological diversity refers to genetic, species, and ecosystem variation. Comparative anatomy, embryology, and other evidence provide support for the theory of evolution.

Uploaded by

ayaan.huss207
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© © All Rights Reserved
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Year 11 Biology- Module 3

3.1 Selection Pressures- A group of organisms of the same species living


together and interacting with their environment is a population. Their
interactions can cause change in the environment.
Abiotic- Includes non-living components including temperature, salinity and
dissolved gases.
- Amount of water
- Quality of water
- Temperature
- Light
Biotic- Includes living components.
- Food
- Reproductive rates
- Predators
Case Study: Prickly Bear

Case Study: Cane Toads


3.2 Adaptations
An adaptation is a characteristic that an organism has
inherited and that makes it suited to its environment. The
three types of adaptations that are found in organisms are:
1. Structural- How an organism is built. (A bilby’s large ears are for
radiating heat off their body)
2. Physiological- How an organism’s functions and increases chance of
survival. (Venomous animals produce poison to catch their prey, to
protect themselves or to ward off predators)
3. Behavioural- How an organism behaves to improve chance of survival.
(Zebras living in herds)

3.3- Biological Diversity


Refers to the variety of all forms of life on earth, the characteristics that the
living organisms have and the variety of ecosystems of which they provide
habitats for organisms.
1. Genetic diversity- which refers to the total number of genetic
characteristics.
2. Species Diversity- the measure of diversity of different species
3. Ecosystem diversity- the variation of different organisms found in a
region.
Divergent: when closely related species, acquire enough variations in their
genetic traits, causing a split into distinct species. (Finches and Kangaroos)
Convergent: when two unrelated species develop similar traits because they
live in similar environments
Punctuated equilibrium and gradualism are two types of evolution that occur
in a species. A species can exhibit one or both evolutionary patterns.
3.4 Evidence in support of the Theory of Evolution by
Natural Selection

Biochemistry: The study of chemicals and reactions


found in cells
Amino Acid Sequencing:

Comparative Anatomy: the study of similarities and


differences in the structure (anatomy) of living organisms.
- Homologous- organs that have the same basic plan to
their structure, however, have modifications because
they are used in different ways and have the same
evolutionary origins.
- Analogous- perform the same function but are different
in structure. (Wings of butterfly and birds) (suggests that
organisms are not closely related, but features of
convergent evolution)

Comparative Embryology: (fish birds and mammals


show the presence of gill slits)
- The greater the number of similarities in structure of organisms being
compared, the more closely related the organisms appear to be.
- Relative Dating: relies on assumptions that fossils found higher in the
rick in younger is lower fossils.
- Chemical Analysis- the measuring amount of chemicals in bones
- Stratigraphy- relies on sedimentary rocks being formed in layers with
the oldest rocks on top and youngest on the bottom.
- Biostratigraphy- involving comparing fossils in different strata.
- Absolute Dating- enables the actual age of a specimen to be found using
radioactive elements.

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