Untitled Quiz

Evolution

• Evolution is the process of how living organisms change over time through genetic material changes.
• Natural selection is the process where organisms with better traits are more likely to survive and pass on to their offspring, resulting in adaptation.
• An adaptation is a modification that arose in an organism (favored by natural selection) to make the organism more fit to exist in their environment.
• Homologous structures share a common ancestor but not a common function.
• Analogous structures do not share a common ancestor but have a common function.

Population Genetics

• A population is a group of organisms of the same species that live in the same geographic area and can reproduce with one another.
• A gene pool is the sum of all alleles of a gene in the population.
• Genotypic frequency shows the percentages of individuals possessing each genotype in a population (AA, Aa, aa).
• Allele frequency shows the percentages (frequencies) of different alleles in a population (A and a).
• The Hardy-Weinberg Principle models a diploid population without natural selection, genetic drift, mutation, and gene flow.
• The Hardy-Weinberg Principle is not possible in nature because these factors always have a part in real populations.

Processes Affecting Genetic Diversity

• Mutation: Changes in the DNA sequence.
• Genetic drift: Random changes in allele frequencies, particularly significant in small populations.
• Gene flow: Movement of alleles between populations.
• Non-random mating: Individuals choose their mates based on specific traits.
• Natural selection: Individuals with advantageous traits are more likely to survive and reproduce.

Examples of Processes Affecting Genetic Diversity

• A hurricane wiping out all homozygous recessive (aa) individuals is an example of natural selection (directional selection).
• A small group of individuals leaving to colonize a new region is an example of genetic drift (founder effect).
• As a population migrates and mates with other populations, new alleles are introduced - this is an example of gene flow.

Fossils

• Fossils form when an organism is buried by sediment and is preserved over millions of years.
• The oldest fossils are found in the lowest layers of sedimentary rock.

Microevolution vs Macroevolution

• Microevolution: small changes in the genetic makeup of a population in a short period.
• Macroevolution: large evolutionary changes between species over a longer period, leading to new species and taxonomic diversification.

Speciation

• A few birds stranded on an island developing adaptations specific to their new environment and being unable to mate with mainland birds demonstrates speciation.
• Speciation is the process of new species forming.

Types of Speciation

• Allopatric speciation requires a physical barrier between populations.
• Sympatric speciation can occur due to environmental differences.

Taxonomy

• Taxonomy is the science of classifying organisms based on shared characteristics.
• The 7 taxa of the taxonomic hierarchy are Kingdom, Phylum, Class, Order, Family, Genus, Species.
• Scientists use phylogenetic trees to depict evolutionary history of organisms using derived traits.
• Phylogenetic trees show the evolutionary relationships between species.

Prokaryotes

• Prokaryotes key characteristics:
  • Nucleoid: where the single DNA is located.
  • Cell Wall: Provides support/protection.
  • Plasma membrane: Regulates the movement of substances in and out the cell.
  • Ribosomes: Responsible for protein synthesis.
  • Cytoplasm: Cellular processes occur.
• The microbiome refers to the bacteria and other microorganisms that live on and in us.
• Some microbiome bacteria can aid in digestion, reproductive health, and protect against infection.

Protists

• Most eukaryotic supergroups belong to the Protista kingdom.
• Photoautotrophic protists use photosynthesis for energy.
• Heterotrophic protists usually eat other organisms to get energy.

Early Plants

• Early plants have sperm with flagella, requiring water for sperm to swim to the eggs.
• Seed plants do not require water for reproduction.

Plant Life Cycles

• The sporophyte generation dominates the plant life cycle in all vascular plants.
• Seed plants can live in dryer habitats because pollen grains and eggs have protective coverings.
• Pollination is the transfer of pollen to the stigma and pistil.
• Fertilization occurs when the sperm and egg fuse.

Angiosperms

• Angiosperms produce flowers and fruits.
• The stamen is the male reproductive organ and contains the anther and filament.
• The pistil is the female reproductive organ and contains the style, stigma, ovary, and ovule.
• The anther holds the pollen (sperm).
• The ovary holds the egg.

Monocots vs Dicots

• Monocots and dicots are two categories of angiosperms.
• Monocots have one cotyledon, parallel leaf veins, fibrous root systems, vascular bundles scattered in stem, and flower parts in multiples of three.
• Dicots have two cotyledons, net-like leaf veins, taproot system, vascular bundles arranged in a ring, and flower parts in multiples of four or five.
• The ovule matures into seeds after fertilization.
• The ovary becomes the fruit.

Plant Tissues

• Plants have three main tissue categories:
  • Dermal tissue: protective outer layer.
  • Vascular tissue: transporting water and nutrients.
  • Ground tissue: providing support/storage for food and water.
• The three simple tissues are:
  • Parenchyma: carries out photosynthesis and growth.
  • Collenchyma: provides flexible support.
  • Sclerenchyma: forms strong fibers for sturdy structural support.
• The two complex tissues are xylem and phloem.
• Xylem transports water and minerals.
• Phloem transports sugars.

Stems

• Stems support the plant and transport water and minerals from roots to leaves.
• Plants grow from meristematic cells.
• Primary growth elongates roots and shoots and occurs at apical meristems.
• Secondary growth thickens roots and shoots and occurs at lateral meristems.

Angiosperm vs Gymnosperm Life Cycles

• In angiosperms, the female gametophyte is enclosed in the ovule within the ovary.
• In gymnosperms, the female gametophyte is present on exposed bracts of the female cone.
• Double fertilization, absent in gymnosperms, is a key event in the angiosperm lifecycle.

Double Fertilization

• Double fertilization occurs when one pollen grain delivers two sperm cells: one fertilizes the egg, and the other fuses with the polar nuclei to form the endosperm.
• Endosperm is a nutrient source for the developing seed.

Pollination

• Pollinators contribute to the success of angiosperms by transferring pollen from the anther to the stigma.

Animals

• Animals are heterotrophs, meaning they cannot produce food and must consume other organisms to obtain energy.
• Some animals are single-celled, like amoeba, paramecium, and euglena.

Animal Embryonic Development

• The inner layer of an animal embryo is the endoderm.
• The outer layer is the ectoderm.
• The middle layer is the mesoderm.
• Animals with only two layers are missing the mesoderm.

Animal Symmetry

• Porifera (sponges) are asymmetrical.
• Animals with bilateral symmetry are divided into protostomes and deuterostomes.
• Protostomes develop the mouth first, while deuterostomes develop the anus first.

Body Cavities

• A coelom is a fluid-filled body cavity that is completely lined by mesoderm.
• A pseudocoelom is a body cavity that is only partially lined by mesoderm.
• Acoelomates lack a body cavity.

Phylum Porifera

• Sponges belong to the phylum Porifera.
• Most sponges are hermaphroditic, meaning they have both sperm and eggs.

Phylum Cnidaria

• Cnidarians have radial symmetry.
• The two body shapes in Cnidarians are polyp and medusa.
• Polyps are attached to something and have a mouth pointing upward.
• Medusas are unattached and floating and have a mouth pointing downward.
• Examples of Cnidarians include jellyfish, corals, sea anemones, and hydroids.

Phylum Platyhelminthes

• Flatworms belong to the phylum Platyhelminthes.
• They are acoelomates with bilateral symmetry.
• They have a digestive system with one opening.
• Examples include planarians, flukes, and tapeworms.

Phylum Nematoda

• Roundworms belong to the phylum Nematoda.
• They are pseudocoelomates with bilateral symmetry.
• They have a complete digestive system with a mouth and anus.
• They are found in various habitats, including soil, water, and animals.

Phylum Annelida

• Segmented worms belong to the phylum Annelida.
• They are coelomates with bilateral symmetry.
• They have a closed circulatory system.
• They have a segmented body and a well-developed nervous system.
• Examples include earthworms, leeches, and polychaetes.

Phylum Mollusca

• Mollusks belong to the phylum Mollusca.
• They are coelomates with bilateral symmetry.
• They have a soft body usually enclosed in a hard shell.
• They have a muscular foot for movement and a mantle for secreting the shell.
• Examples include snails, slugs, clams, oysters, squids, and octopuses.

Phylum Arthropoda

• Arthropods belong to the phylum Arthropoda.
• They are the most diverse animal phylum.
• They are coelomates with bilateral symmetry.
• They have a hard exoskeleton, jointed appendages, and a segmented body.
• Examples include insects, spiders, crabs, lobsters, and scorpions.

Phylum Echinodermata

• Echinoderms belong to the phylum Echinodermata.
• They are coelomates with radial symmetry.
• They have a spiny skin and a water vascular system for movement.
• They are found in marine environments.
• Examples include starfish, sea urchins, sea cucumbers, and brittle stars.

Phylum Chordata

• Chordates belong to the phylum Chordata.
• They are coelomates with bilateral symmetry.
• They have a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail at some point in their development.
• They include vertebrates and some invertebrates.
• Examples include fish, amphibians, reptiles, birds, mammals, and tunicates.

Vertebrates

• Vertebrates are a subphylum of Chordates.
• They have a backbone (vertebral column) and a skull.
• They have a closed circulatory system and a well-developed brain.

Chordate Characteristics

• Notochord: a flexible rod that provides support.
• Dorsal hollow nerve cord: a tube of nerve tissue that runs along the back.
• Pharyngeal slits: openings in the throat that are used for filter feeding in some species.
• Post-anal tail: a tail that extends beyond the anus.

Fish

• Fish are the most diverse group of vertebrates.
• They have gills for breathing underwater, fins for swimming, and scales for protection.

Amphibians

• Amphibians are a group of vertebrates that live both in water and on land.
• They have smooth skin and moist skin that helps them breathe through their skin.

Reptiles

• Reptiles are a group of vertebrates that are adapted to live on land.
• They have dry, scaly skin that prevents water loss.
• They lay eggs that have a shell.

Birds

• Birds are a group of vertebrates that are adapted for flight.
• They have feathers for insulation and flight.
• They have hollow bones that make them lighter.

Mammals

• Mammals are a group of vertebrates that have hair or fur.
• They give birth to live young and nourish them with milk.
• They are endothermic, meaning they use body heat to maintain their temperature.

Animal Tissues

• Epithelial tissue covers the body surface and lines cavities.
• Connective tissue supports and connects tissues.
• Muscular tissue allows for movement.
• Nervous tissue conducts electrical pulses for communication.

Organ Systems

• The digestive, cardiovascular, and respiratory systems work together for energy usage.

Neurons

• Neurons are the cells of the nervous system.
• They have a cell body (soma), dendrites, an axon, a myelin sheath, and an axon terminal.
• Dendrites receive input from other cells.
• Axons transmit electrical impulses to other neurons.
• The myelin sheath insulates the axon, protecting the neuron and speeding up electrical impulses.
• The axon terminal transmits electrical and chemical signals to other neurons and effector cells.

Endocrine System

• The endocrine system is a network of glands that produce and secrete hormones.
• Hormones are chemical messengers that travel through the bloodstream and regulate various bodily functions.

Endocrine Glands

• Hypothalamus: regulates feeling patterns, temperature, and homeostasis.
• Pituitary gland: produces hormones that regulate other glands.
• Adrenal glands: help the body deal with stress.
• Pineal gland: regulates the sleep cycle.
• Thyroid gland: controls metabolism.
• Parathyroid gland: controls calcium levels in the bloodstream.
• Thymus gland: stimulates the development of antibodies.
• Pancreas: regulates blood glucose levels and keeps the body energized.
• Ovaries: produce estrogen and eggs in females.
• Testes: produce testosterone and sperm in males.

Steroid Hormones

• Steroid hormones are a type of hormone that belongs to the chemical compound class known as steroids.

Open vs Closed Circulatory Systems

• Open circulatory systems have blood flowing freely through open spaces and hemolymph (mixes with interstitial fluid).
• Closed circulatory systems have blood flowing within a network of vessels (arteries and veins).