Bio exam review

Diversity of Living Things

1. Levels of Classification:

   • Domain: Biggest group (e.g., Bacteria, Archaea, Eukarya).

   • Kingdom: Next group (e.g., Animals, Plants).

   • Phylum: Groups within kingdoms (e.g., Chordates, which include humans).

   • Class, Order, Family, Genus, Species: These get more specific. For example, humans are Homo sapiens (Genus Homo, Species sapiens).

2. Taxonomy and Phylogeny: Taxonomy is the system of naming and classifying organisms. Phylogeny shows how species are related over time based on their common ancestors.

3. Genus and Species:

   • Genus: A group of species that are closely related (e.g., Homo includes humans, Pan includes chimpanzees).

   • Species: A group of organisms that can breed and produce fertile offspring (e.g., Homo sapiens is the species for humans).

4. Prokaryotes vs. Eukaryotes vs. Viruses:

   • Prokaryotes: Simple, single-celled organisms without a nucleus (e.g., bacteria).

   • Eukaryotes: More complex, with a nucleus and organelles (e.g., plants, animals).

   • Viruses: Tiny infectious particles that need a host to survive; they don't have cells.

5. Genetic Variation: Differences in genes within a population help organisms adapt to new challenges (e.g., changing climate). This helps some survive when others can't.

6. Kingdom Characteristics:

   • Plants: Multicellular, photosynthesize.

   • Animals: Multicellular, eat other organisms.

   • Fungi: Multicellular (mostly), break down organic material.

   • Bacteria: Single-celled, no nucleus, can be helpful or harmful.

7. Biodiversity: The variety of life. It’s important because ecosystems depend on different organisms to keep things balanced.

8. Evolutionary Changes: Over time, organisms change. For example, simple cells (prokaryotes) became complex cells (eukaryotes). Plants evolved from simple, single-celled organisms.

9. Key Terms:

   • Genetic Diversity: The variety of genes in a population.

   • Species Diversity: The variety of different species in an ecosystem.

   • Morphology: The structure/form of organisms (e.g., shapes, sizes).

10. Sexual Reproduction: It mixes genes from two parents, creating more genetic diversity, which helps species adapt to environmental changes.

11. Dichotomous Key: A set of questions that helps you figure out what organism you have based on its features (e.g., “Does it have wings?”).

12. Phylogenetic Trees/Cladograms: Diagrams that show the evolutionary relationships between species.

13. Human Impact: Human actions (pollution, deforestation) can harm ecosystems and reduce biodiversity.

14. Climate Change: Can change where species live and how they interact with each other, threatening biodiversity.

Evolution

1. Theory of Evolution: The idea that species change over time due to natural selection, where organisms with helpful traits are more likely to survive and reproduce.

2. Adaptation: Changes in an organism that help it survive in its environment (e.g., giraffes with long necks can reach high leaves).

3. Speciation: The process where new species are created from an existing one due to differences in environment or behavior.

4. Evolution Mechanisms:

   • Natural Selection: Organisms with traits that help them survive are more likely to reproduce.

   • Artificial Selection: Humans breed plants/animals for specific traits (e.g., dog breeding).

   • Sexual Selection: Traits that help an organism attract a mate (e.g., peacock feathers).

   • Genetic Drift: Random changes in traits in a population (e.g., due to a natural disaster).

5. Contributions of Scientists: Charles Darwin’s ideas about evolution by natural selection changed how we understand species development.

6. Natural/Artificial Selection Case Studies: Research shows how certain traits become common in a population over time.

7. Key Terms:

   • Extinction: When a species no longer exists.

   • Mimicry: When one species looks like another to avoid predators.

   • Adaptation: How a species changes to better survive.

   • Mutation: Changes in DNA that can create new traits.

8. Environmental Changes: Can alter what traits are beneficial, affecting natural selection.

9. Hardy-Weinberg: A formula used to calculate allele frequencies in a stable population.

Genetic Continuity

1. DNA Replication: DNA makes a copy of itself before cell division, ensuring each new cell has the same genetic information.

2. Mitosis: The process of a cell dividing into two identical cells for growth or repair. The phases are:

   • Prophase: Chromosomes condense.

   • Metaphase: Chromosomes line up in the middle.

   • Anaphase: Chromosomes are pulled apart.

   • Telophase: Two new nuclei form.

3. Meiosis: A type of cell division that makes sex cells (sperm/eggs). It reduces the chromosome number by half. The phases are similar to mitosis, but it happens twice, making four cells instead of two.

4. Crossing Over: During meiosis, chromosomes exchange bits of DNA, creating new combinations and increasing diversity.

5. Mitosis vs. Meiosis:

   • Mitosis: One division, two identical cells (growth, repair).

   • Meiosis: Two divisions, four different sex cells (for reproduction).

6. Genetic Terms:

   • Gene: A section of DNA that controls a trait.

   • Allele: Different versions of a gene (e.g., blue vs. brown eyes).

   • Dominant: An allele that shows its effect even if only one copy is present.

   • Recessive: An allele that only shows its effect if two copies are present.

   • Genotype: The genetic makeup (e.g., Bb for brown eyes).

   • Phenotype: The physical trait (e.g., brown eyes).

7. Punnett Squares: A tool used to predict the genetic outcome of a cross. You can use it to figure out the chance of a certain trait showing up in offspring.

8. Incomplete Dominance & Codominance:

   • Incomplete Dominance: The traits blend (e.g., red and white flowers make pink).

   • Codominance: Both traits show up (e.g., a red and white flower shows both colors).

9. Sex-Linked Traits: Traits controlled by genes on sex chromosomes (X or Y).

   • For example, color blindness is a sex-linked trait carried on the X chromosome.

10. Genetic Disorders: Diseases caused by mutations in genes (e.g., Sickle Cell Anemia makes red blood cells sickle-shaped, causing health problems).

11. Karyotype: A picture of an individual’s chromosomes. It can show genetic disorders like Down syndrome (extra chromosome 21).

Internal Systems and Regulation

1. Respiratory System: Oxygen enters through the nose/mouth, travels to the lungs, and then is absorbed by blood. Hemoglobin in red blood cells carries it to cells.

2. Breathing vs. Respiration: Breathing is the physical act of taking in oxygen and releasing carbon dioxide, while respiration is the chemical process inside cells that turns oxygen into energy.

3. Lung Volumes:

   • Tidal Volume: Normal breath.

   • Vital Capacity: Maximum amount of air you can exhale.

4. Heart and Circulatory System: The heart pumps blood, and blood vessels carry it throughout the body.

   • Arteries carry oxygen-rich blood away from the heart.

   • Veins bring oxygen-poor blood back to the heart.

5. Digestive System: Food passes from the mouth through the esophagus, stomach, small intestine (where nutrients are absorbed), and large intestine (where water is absorbed).

6. Enzymes: Help break down food. For example, amylase in the mouth breaks down starch, and lipase in the small intestine breaks down fats.