Biol 1407 Unit 1 Study Guide: Evolution

Chapter 22: Descent with Modification

• Scientists who influenced Darwin: Hutton, Cuvier, Lyell, Wallace, etc.
• Darwin's 5-year voyage on the HMS Beagle and publication of "The Origin of Species" in 1859
• Definition of evolution: the process by which species accumulate differences from their ancestors as they adapt to different environments over time
• Population evolution: individuals do not evolve, but populations change over time genetically
• Natural selection: the process in which individuals with certain inherited traits tend to survive and reproduce at higher rates because of those traits
• 4 observations of natural selection:
  • Individuals in populations vary in their inherited traits
  • All species can produce more offspring than the environment can support, leading to unequal survival and reproduction
  • Individuals with inherited traits that increase survival and reproduction in an environment tend to produce more offspring
  • The unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations

Artificial Selection and Evidence of Evolution

• Artificial selection: humans modify species through breeding individuals with desired traits
  • Examples: staple crops, domesticated animals, horses, dogs, broccoli, cabbage, rice, corn, etc.
• Evidence of evolution:
  • Direct observation: antibiotic resistance, birds' beak size and fruit size
  • Homology: similarity from common ancestry
    • Anatomical homology (homologous structures)
    • Comparative embryology
    • Vestigial structures (e.g. goosebumps, wisdom teeth, ear muscle, tailbone of human)
    • Molecular homology (DNA)
  • Fossil records: 3.5 billion years ago
  • Biogeography: the scientific study of the geographic distribution of species (continental drift and the distribution of modern living organisms)

Homologous vs. Analogous Structures

• Homologous structures: similar structures due to common ancestry
• Analogous structures: similar structures due to convergent evolution (e.g. streamlined body shapes of dolphin and shark)

Chapter 23: The Evolution of Populations

• Microevolution: changes in allele frequencies in populations over generations, evolution at its smallest scale
• Three mechanisms of allele frequency change:
  • Natural selection
  • Genetic drift
  • Gene flow
• Genetic variation: the differences in genes or other DNA sequences among individuals
• Sources of genetic variation:
  • Mutation
  • Gene duplication
  • Sexual reproduction

Hardy-Weinberg Equilibrium

• Conditions for equilibrium: no mutation, random mating, no natural selection, extremely large population size, no gene flow
• Hardy-Weinberg equation: p + q = 1, p2 + 2pq + q2 = 1

Chapter 24: The Origin of Species

• Speciation: the process by which one species splits into two species
• Macroevolution: broad patterns of evolutionary change above the species level (the formation of new species)
• Biological species concept:
  • Defined by the populations' ability to interbreed and produce fertile offspring
  • Limitations: cannot be applied to fossils or asexual organisms
• Morphological species concept:
  • Mainly depends on anatomical physical features
  • Not as accurate as the biological species concept
  • Limitation: relies on subjective criteria
• Ecological species concept:
  • Defines species by its ecological niche

Reproductive Isolation

• Prezygotic and postzygotic isolations
• Prezygotic isolation: blocks fertilization
  • Habitat isolation
  • Temporal isolation
  • Behavioral isolation
  • Mechanical isolation
  • Gametic isolation
• Postzygotic isolation: (occurs after fertilization) prevents hybrid zygotes from developing into fertile offspring
  • Reduced hybrid viability
  • Reduced hybrid fertility
  • Hybrid breakdown

Speciation

• Allopatric speciation: populations are geographically isolated
• Sympatric speciation: speciation occurs in populations that live in the same geographic area
• Polyploidy: instant speciation, common in plants
• Sexual selection: drives speciation through mate choice for certain traits
• Habitat differentiation: the exploitation of new habitats or resources

Chapter 25: The History of Life on Earth

• The formation of Earth: about 4.6 billion years ago
• The oldest prokaryote fossils: 3.5 billion years ago
• The oldest eukaryote fossils: 1.8 billion years ago
• Radiometric dating: how fossils are dated, using radioactive isotopes
• Geologic record: Cambrian explosion (many animal phyla appear suddenly in the fossils of the Cambrian period, 535-525 million years ago)
• Endosymbiosis:
  • Origin of eukaryotic organisms
  • Both mitochondria and plastids are thought to have descended from bacteria
  • Serial endosymbiosis

Mass Extinctions

• Occur when large numbers of species rapidly become extinct worldwide
• Five mass extinctions have been documented
• Paved the way for adaptive radiation (a rapid period of evolutionary change where many new species arise and adapt to different ecological niches)

Protists

• An informal term used to refer to all eukaryotes that are not plants, animals, or fungi.
• Eukaryotes with a nucleus and other membrane-enclosed organelles.
• Most protists are unicellular, but some are multicellular.
• Nutritionally diverse, including photoautotrophs, heterotrophs, and mixotrophs.
• Four groups: Excavata, SAR, Archaeplastida, and Unikonta.
• Examples: Trypanosoma (causes sleeping sickness), Euglena (mixotrophs), Diatoms (unicellular algae with a glass-like wall), Brown algae (multicellular algae), Dinoflagellates (marine and freshwater phytoplankton), Plasmodium (parasite causing malaria), Paramecium (uses cilia to move and feed).

Fungi

• Heterotrophs that absorb nutrients from outside their bodies.
• Mostly multicellular, but some are unicellular (e.g., yeast).
• Closer to animals than plants.
• Cell walls made of chitin.
• Sexual and asexual reproduction.
• Body structure: hyphae (tubular cell walls strengthened with chitin), mycelium (interwoven mass of hyphae).
• Roles: decomposers, mutualists, pathogens (e.g., ringworm, yeast infection), medicine (e.g., penicillin).
• Mutualism: mycorrhiza (fungi and plant roots), lichen (symbiotic association between fungi and photosynthetic microorganisms).

Plant Diversity

• Role of plants: oxygen, food sources, habitat for many land organisms.
• Similarities between plants and algae: multicellular, eukaryotic, photosynthetic autotrophs, cellulose cell walls, chloroplasts.
• Green algae (charophytes) are closest relatives of plants.
• Differences between charophytes and plants: alternation of generations, walled spores, apical meristems, cuticle, and stomata.
• Evolution of plants: from cyanobacteria to green algae to land plants.

Plant Structure

• Hierarchical organization: cell, tissue, organ, organism.
• Plant organs: roots (root system), stems and leaves (shoot system).
• Root: anchoring, absorbing minerals and water, storing carbohydrates.
• Stem: elongating, orienting shoot to maximize photosynthesis.
• Leaf: photosynthetic organ, exchanging gases, dissipating heat, defending against herbivores and pathogens.
• Monocots and eudicots differ in vein arrangement, vascular tissue, and cell structure.

Resource Acquisition and Transport

• Xylem: transports water and minerals from roots to shoots.
• Phloem: transports photosynthetic products from where they are made to where they are needed.
• Stomata: pores necessary for CO2 diffusion into photosynthetic tissues.
• Mycorrhizae: symbiotic fungi increase surface area for absorbing water and minerals.
• Aquaporins: transport proteins facilitating water passage across cell membranes.

Soil and Plant Nutrition

• Essential elements: 17 chemical elements required for plant life cycle and reproduction.
• Macronutrients: 9 elements required in large amounts (e.g., carbon, oxygen, nitrogen).
• Micronutrients: 8 elements required in small amounts.
• Nitrogen fixation: conversion of atmospheric nitrogen into nitrate.
• Plant mutualism with soil bacteria: rhizobacteria and endophyte.
• Mycorrhizae: symbiotic relationship between plants and fungi.

Angiosperm Reproduction

• Angiosperm anatomy: flowers (reproductive shoots), carpels, stamens, petals, sepals.
• Angiosperm life cycle: gametophyte development, sperm delivery, double fertilization, seed development.
• Pollination: transfer of pollen from anthers to stigma.
• Double fertilization: fusion of gametes to form zygote and endosperm.
• Fruits: mature ovary of a flower, protecting seeds and aiding in seed dispersal.
• Asexual reproduction: producing offspring from a single parent without gamete fusion.
• Sexual reproduction: generating genetic variation for evolutionary adaptation.

Animal Diversity

• Animals are characterized by their ability to move, capture prey, and be multicellular, heterotrophic, and eukaryotic. • Animals are thought to have evolved from flagellated protists, with their closest living relatives being choanoflagellates. • The Cambrian explosion marks a period of rapid animal diversification. • Animal body plans exhibit either radial symmetry or bilateral symmetry, with most animals having bilateral symmetry. • Embryo development in animals involves cleavage, a succession of cell divisions without growth between divisions, leading to the formation of a blastula. • Animal tissues are composed of few groups, with most having germ layers that give rise to tissues and organs. • Body cavities in animals include the coelom, hemocoel, and some having no cavity at all.

Invertebrates

• Invertebrates are animals without a backbone, including Porifera (sponges), Cnidaria, Lophotrochozoa, Flatworms (Platyhelminthes), Molluscs, Annelids, Ecdysozoans, Nematodes, and Arthropods.

Chordates

• Chordates are characterized by bilateral symmetry, deuterostome development, and the presence of a notochord, dorsal nerve cord, pharyngeal pouches, and post-anal tail. • Chordates include both invertebrates (lancelets and tunicates) and vertebrates.

Vertebrates

• Vertebrates are characterized by the presence of a backbone, with four groups: fish, amphibians, reptiles, and mammals. • Fish include hagfishes, lampreys, sharks, and ray-finned and lobe-fin fish. • Amphibians, such as frogs and salamanders, undergo metamorphosis and need both water and land for living. • Reptiles have scales, shelled and amniotic eggs, and are ectothermic. • Birds are endothermic, direct descendants of dinosaurs, and have unique characteristics. • Mammals are characterized by the presence of mammary glands, hair, and endothermy.

Animal Form and Function

• Tissues are groups of cells with similar appearance and function. • There are four types of tissues: epithelial, connective, muscle, and nervous tissues. • Epithelial tissue covers the outside of the body and lines organs and cavities. • Connective tissue holds tissues and organs together and provides support. • Muscle tissue is responsible for movement, with three types: skeletal, smooth, and cardiac. • Nervous tissue functions in the receipt, processing, and transmission of information.

Animal Nutrition

• Diet varies among animals, with herbivores, carnivores, and omnivores. • Food processing involves ingestion, digestion, absorption, and elimination. • Most animals have a complete digestive system with a mouth, pharynx, esophagus, stomach, small intestine, and large intestine. • The digestive system is specialized for different functions, with the stomach breaking down proteins and the small intestine absorbing macromolecules.

Circulation and Respiration

• Circulatory systems are either open or closed, with insects, arthropods, and some molluscs having open systems and annelids, cephalopods, and vertebrates having closed systems. • The human cardiovascular system consists of the heart, blood vessels, and blood. • The heart is a muscular organ that pumps blood throughout the body. • Blood vessels are arteries, veins, and capillaries, with different functions. • Gas exchange occurs in capillary beds, with oxygen-rich blood returning to the heart and oxygen-poor blood flowing to the lungs.

Immune System

• Pathogens, such as viruses, bacteria, and fungi, cause disease. • The immune system has two types of immunity: innate and adaptive. • Innate immunity is non-specific, active immediately upon infection, and involves barrier defenses, cellular defense, and inflammation. • Adaptive immunity is specific, develops more slowly, and is enhanced by previous exposure to the pathogen.

Osmoregulation

• Osmoregulation controls solute concentrations and balances water gain and loss. • Animals need to remove nitrogenous waste products, with different methods used by different groups.

Hormones

• Hormones are secreted molecules that circulate through the body and stimulate specific cells. • The endocrine system uses hormones for chemical signaling, while the nervous system uses a network of neurons. • Hormones can be polypeptides, steroids, or amines. • Feedback regulation involves negative and positive feedback mechanisms. • The hypothalamus coordinates endocrine signaling, with signals traveling to the pituitary gland. • The pituitary gland stores and secretes hormones made in the hypothalamus. • Antagonistic hormone homeostasis is achieved by hormones such as insulin and glucagon.

Chapter 46: Animal Reproduction

• Sexual reproduction: creation of offspring by fusion of haploid gametes, advantages: genetic variation, disadvantages: energy-intensive
• Asexual reproduction: creation of offspring without fusion of gametes, advantages: rapid reproduction, disadvantages: lack of genetic variation
• Examples of animals that reproduce sexually: most vertebrates, examples of animals that reproduce asexually: sponges, hydra, and some invertebrates

Fertilization and Reproductive Organs

• Fertilization: union of egg and sperm, requires moist habitat for external fertilization
• Internal fertilization: enables sperm to reach egg in dry environment, survival chances are higher
• Male reproductive organs: testes, epididymis, vas deferens, urethra
• Female reproductive organs: ovaries, oviducts, uterus

Gametogenesis

• Gametogenesis: production of gametes from germ cells, mutations can pass to offspring
• Spermatogenesis: formation of sperm, creates 4 sperm
• Oogenesis: development of mature egg, creates 1 egg, stops at menopause

Hormones in Reproduction

• Hypothalamus: secretes GnRH, directs release of FSH and LH from anterior pituitary
• FSH and LH: stimulate sex hormone production by gonads
• Sex hormones: testosterone, estrogens (estradiol and progesterone), regulate ovarian and menstrual cycles

Conception and Menopause

• Conception: fertilization of egg by sperm in oviduct
• Menopause: end of ovarian and menstrual cycles in females

Chapter 48: Neurons, Synapses, and Signaling

Neurons

• Neurons: nerve cells that transfer information within the body
• Structure of a neuron: cell body, dendrites, axon, synapse
• Functions of neurons: transmit information, integrate information, transmit signals to muscle cells

Neurotransmitters and Signaling

• Neurotransmitters: chemical messengers that pass information from transmitting neuron to receiving cell
• Mechanisms of signal transmission: resting potential, action potential, depolarization

Chapter 49: Nervous Systems

Nerve and CNS

• Nerve: axons of multiple neurons bundled together
• CNS: central nervous system (brain and spinal cord)

PNS and Glial Cells

• PNS: peripheral nervous system (neurons carrying information in and out of CNS)
• Glial cells: supporting cells of neurons, nourish, support, and regulate neurons

Brain Structure

• Forebrain: cerebrum, thalamus, hypothalamus, amygdala
• Midbrain
• Hindbrain: cerebellum, medulla, pons

Chapter 52: An Introduction to Ecology and the Biosphere

Ecology

• Ecology: scientific study of interactions between organisms and their environment
• Subfields: population ecology, community ecology, ecosystem ecology

Biomes

• Terrestrial biomes: tropical rain forests, deserts, savannas, chaparral, temperate grasslands, coniferous forests, temperate forests, tundra
• Aquatic biomes: marine biomes (estuary, intertidal zone, ocean pelagic zone, coral reefs, marine benthic zone), freshwater biomes (lakes, wetlands, streams, and rivers)

Chapter 53: Population Ecology

Population

• Population: group of individuals of the same species living in an area
• Population density: number of individuals per unit area
• Population dispersion: pattern of spacing among individuals within the population

Population Growth

• Exponential growth: growth rate is proportional to population size
• Logistic growth: growth rate slows as population approaches carrying capacity

Factors Affecting Population Size

• Density-dependent factors: death rate increases or birth rate decreases with increasing density
• Density-independent factors: birth rate or death rate does not change with population density

Chapter 54: Community Ecology

Interspecific Interactions

• Competition: individuals of different species use a resource that limits survival and reproduction
• Exploitation: one species benefits while the other species is harmed
• Mutualism: both species benefit
• Commensalism: one species benefits while the other species is not affected

Defense Mechanisms

• Aposematic coloration: bright warning coloration
• Cryptic coloration: camouflage
• Batesian mimicry: palatable species mimics unpalatable model
• Mullerian mimicry: two or more unpalatable species resemble each other

Chapter 55: Ecosystems and Restoration Ecology

Ecosystems

• Ecosystem: all living organisms in an area and the abiotic factors with which they interact
• Energy flow: energy enters ecosystems as sunlight, is converted to chemical energy, and is transferred to heterotrophs
• Chemical cycling: cycling of nutrients between organisms and their environment

Trophic Structure

• Trophic structure: feeding relationships between organisms in a community
• Energy transfer: energy is transferred from autotrophs to heterotrophs

Ecological Succession

• Ecological succession: pattern of colonization and species replacement following a disturbance
• Primary succession: colonization of new area
• Secondary succession: replacement of species in an area that has been disturbed

Chapter 56: Conservation Biology and Global Change

Biodiversity

• Biodiversity: genetic diversity, species diversity, and ecosystem diversity
• Threats to biodiversity: habitat loss, introduced species, overharvesting, global change

Conservation Biology

• Conservation biology: study of preserving and protecting biodiversity
• Biodiversity hotspots: areas with high levels of endemism and many endangered species

Global Change

• Global change: alterations in climate, atmospheric chemistry, and broad ecological systems that reduce Earth's capacity to support life
• Climate change: human activities driving climate change through release of gaseous waste into the atmosphere