SBI3U1 EXAM REVIEW

Effects of decreasing biodiversity

"Loss of ecosystem stability, fewer resources, and reduced resilience to change."

Binomial nomenclature and who invented it

A two-name system (Genus species) created by Carl Linnaeus.

8 levels of taxa in order

"Domain, kingdom, phylum, class, order, family, genus, species”

Purpose of taxonomic lists

To show how related organisms are based on shared characteristics.

Dichotomous key

Tool that helps identify organisms by asking paired questions.

Phylogeny (evidence)

"Fossils, DNA, anatomy, embryology used to show evolutionary relationships."

Phylogenetic trees

Visuals that show evolutionary paths and common ancestors.

Prokaryotes

no nucleus (bacteria)

Eukaryotes

]have a nucleus (plants, animals, fungi)”

Bacteria classification

"By shape (cocci, bacilli, spirilla) and arrangement (chains, clusters)."

Bacteria reproduction

binary fission

protist reproduction

asexual (fission) or sexual (conjugation).

Virus structure

Protein coat (capsid) + DNA/RNA; some have lipid envelopes.

Are viruses living?

"No, they need a host to reproduce and don’t carry out life processes."

Lytic cycle

virus invades the host cell, virus takes over and makes new viruses inside the cell, the virus cells are released, host cell undergoes lysis

lysogenic cycle

dna becomes part of the host dna, when the host copies its dna, the viral dna is copied. the viral dna remains dormant until a stimulus causes the dna to become active and enters the lytic cycle

Viruses

non-living, need host

bacteria

living, reproduce on their own

"Protistsfungi, plant, animal classification"

"Based on cell type, nutrition, reproduction, and movement."

"Structure of bacteria, viruses

Each has unique cell structures: e.g., bacteria = cell wall, protists = nucleus."

Structure of DNA

Double helix with sugar-phosphate backbone and nitrogen bases.

Complementary base pairing

"A-T, G-C”

Haploid vs. Diploid

Haploid = 1 set of chromosomes; Diploid = 2 sets.

Autosomes

body traits;

Sex chromosomes

Determine biological sex (X/Y).

Mitosis in plants vs. animals

"Both divide similarly but plants form a cell plate; animals use cleavage."

Homologous chromosomes

Pairs of chromosomes with same genes but possibly different alleles.

Sister chromatids

Identical copies of a chromosome joined by a centromere.

Nondisjunction

Failure of chromosomes to separate → extra or missing chromosomes.

Karyotype

Image of chromosomes used to detect genetic disorders.

Examples of genetic disorders

"Down (trisomy 21), Turner (XO), Klinefelter (XXY)."

Oogenesis vs. Spermatogenesis

Egg formation (1 egg); sperm formation (4 sperm).

Gregor Mendel

Father of genetics; created laws of segregation and independent assortment.

Genotype vs. Phenotype

Genotype: genes; Phenotype: physical traits.

Homozygous vs. Heterozygous

Homo: same alleles (AA); Hetero: different (Aa).

Monohybrid cross

Cross of one trait using Punnett squares.

Co-dominance

"Both alleles fully expressed (e.g. AB blood)

Incomplete dominance

"Blended phenotype (e.g. red+white=pink)

Genotypic vs. Phenotypic ratio

Genotype: gene combos; Phenotype: physical result counts.

Blood type genetics

"A, B, AB, O, based on co-dominant alleles (IA, IB, i)”

X-linked traits

Carried on X chromosome; males more likely to express.

Dihybrid cross

Cross of two traits; 16-square Punnett square.

Lamarck vs. Darwin

Lamarck: use/disuse; Darwin: natural selection + survival of the fittest.

Scientist similar to Darwin

Alfred Russel Wallace.

Darwin's discoveries

"Mostly in the Galápagos Islands (finches, tortoises)”

Natural selection

Organisms with best traits survive & reproduce.

Does evolution act on individual or population?

Population!

Evidence for evolution

"Fossils, anatomy, molecular, embryology”

Fossil layers

Older fossils are deeper; newer are closer to surface.

Vestigial structures

"Leftover features (e.g. tailbone)

Homologous structures

"Same origin, different function (e.g., bat wing, human arm)."

Analogous structures

"Different origin, same function (e.g., bird wing, insect wing)."

6 Mechanisms of evolution

"Mutation, gene flow, genetic drift, natural selection, non-random mating, speciation."

Sexual selection

"Traits chosen for mating success (e.g. peacock feathers)

Sexual dimorphism

Physical differences between sexes of same species.

Types of natural selection

"Stabilizing, directional, disruptive”

How new variations happen

Mutations or genetic shuffling in meiosis.

Allele frequency

% of each allele in a population (can evolve over time).

Artificial selection

"Humans choose traits; pro = fast results, con = less genetic diversity."

2 types of speciation

"Allopatric (geographic), sympatric (same place)."

When do new species form?

When populations are isolated and can’t interbreed.

3 types of adaptations

"Structural, behaviour, physiological”

2 types of mimicry

"Batesian (harmless mimics harmful), mullerian (harmful mimics harmful)”

Pre-zygotic barriers

habitat, timing, behaviour”

Post-zygotic barriers

After fertilization: hybrid doesn’t develop or is infertile.

Gradualism vs. Punctuated equilibrium

Gradualism = slow changes; Punctuated = fast bursts between long stability.

Digestive system structures

mouth, pharynx, epiglottis, esophagus, stomach, duodenum, small intestine, large intestine, rectum, anus

Peristalsis

Wave-like muscle movement to move food.

Macromolecules & monomers

"Proteins → amino acids, Carbs → sugars, Lipids → fatty acids."

Digestive enzymes

"Amylase (carbs), pepsin (protein), lipase (fats)

Nutrient absorption

"Capillaries (sugars, amino acids), lacteal (fats.”

Insulin & glucagon

"Made in pancreas; Insulin ↓ blood sugar, glucagon ↑ it."

Respiratory system structures

Nose, pharynx, larynx, trachea, lungs, bronchi, bronchioles, alveoli

Filtering in respiratory system

"Nose hairs, mucus, cilia, traps dust and microbes.”

Inhalation vs. exhalation

Inhale: diaphragm contracts; Exhale: diaphragm relaxes.

Breathing rate control

Controlled by CO₂ levels detected by brain.

Circulatory system structures

"Heart, arteries, veins, capillaries”

Hemoglobin

Protein in red blood cells that carries oxygen.

Path of blood flow

"Pulmonary circuit (lungs), systemic circuit (body).”

Homeostasis

"Maintaining internal balance (e.g. body temp, pH)”.

Blood pressure

"Systolic (high), diastolic (low), normal=120/80

Disease examples & treatment

"Asthma (inhalers), Diabetes (insulin), Heartburn (antacids), etc."

Increased surface area examples

"Small intestine (villi), lungs (alveoli), stomach folds for better absorption."