BIOLOGY

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BIOLOGY by Mind Map: BIOLOGY

1. MITOSIS and CELL DIVISION

1.1. Interphase

1.1.1. G1

1.1.1.1. organelles are copied, cell grows in size

1.1.2. S

1.1.2.1. DNA is copied- chromosomes now have sister chromatids

1.1.3. G2

1.1.3.1. DNA is proofread for copying errors

1.2. M phase

1.2.1. Mitosis (nuclear division)

1.2.1.1. Prophase

1.2.1.1.1. chromosomes condense, nucleus dissolves

1.2.1.2. Metaphase

1.2.1.2.1. chromosomes move to middle

1.2.1.3. Anaphase

1.2.1.3.1. chromosomes split apart

1.2.1.4. Telophase

1.2.1.4.1. chromosomes decondense, nuclei reform.

1.2.2. Cytokinesis (cell splits in two)

2. MODES of INHERITANCE

2.1. COMPLETE dominance

2.1.1. When one allele (dominant) completely masks the other allele (recessive) in a heterozygote

2.1.1.1. EXAMPLE: White cat X black cat = BLACK cat

2.2. CO-dominance

2.2.1. When both alleles are equally expressed in a heterozygote

2.2.1.1. EXAMPLE: White cat X black cat = Black AND white cat

2.3. INCOMPLETE (partial) dominance

2.3.1. When neither allele is fully expressed leading to a blended phenotype

2.3.1.1. EXAMPLE: White cat X black cat= GREY cat

3. EVOLUTION

3.1. Evolution is a change in allele frequency over time.

3.1.1. Natural Selection

3.1.1.1. Variation

3.1.1.1.1. eg. via mutation, sexual reproduction (crossing over), gene flow (immigration)

3.1.1.2. Competition for survival

3.1.1.2.1. i.e. “survival of the fittest”

3.1.1.3. Selective pressure

3.1.1.3.1. eg. food resources, predators, natural disasters, availability of mates

3.1.2. ADAPTATION

3.1.2.1. Organisms with beneficial features will be selected FOR

3.1.2.1.1. Over time beneficial adaptations become more common in the population due to differential reproduction, this is EVOLUTION

3.1.2.2. organisms with detrimental features will be selected AGAINST

3.1.3. Evidence of Evolution

3.1.3.1. Fossil record

3.1.3.2. Homologous structure

3.1.3.3. Comparative embryology

3.1.3.4. Molecular evidence

3.1.3.5. Vestigial structures

4. Introduction to INHERITANCE

4.1. GENES

4.1.1. Our features are coded by Genes, which are found on CHROMOSOMES

4.1.1.1. All organisms have 2 copies of each chromosome

4.1.1.1.1. Maternal

4.1.1.1.2. Paternal

4.1.2. There are two copies of every gene

4.1.2.1. These alternate genes are called ALLELES. There are two types of alleles

4.1.2.1.1. HOMOZYGNOUS

4.1.2.1.2. HETEROZYGOUS

4.1.3. GENOTYPE

4.1.3.1. Allele combination for a given gene

4.1.4. PHENOTYPE

4.1.4.1. Physical expression of a gene

4.1.4.1.1. The phenotype is determined by the genotype and ENVIRONMENTAL INFLUENCE