Ecology: Population Dynamics and Interactions

• The lecture covers a range of topics in biology, including animal characteristics, biodiversity, evolution, and ecology.

Animal Characteristics

• Animals are eukaryotic organisms with membrane bound organelles.
• Animals are heterotrophic, they obtain nutrients by consuming other organisms.
• Animal cells lack cell walls.

Endosymbiosis

• Endosymbiosis involves a bacterium engulfing another, resulting in a mutually beneficial relationship.
• The internal bacteria are passed on through generations.

Animal Facts

• Bee Hummingbird: smallest bird.
• Ostrich: largest bird.
• Wandering Albatross: the largest wingspan bird.
• Blue Whale: the largest animal and mammal.
• Etruscan Shrew: smallest mammal by mass.
• Kitti's Hog-Nosed Bat (Bumblebee Bat): smallest mammal by length.
• Giant Tortoise: longest-lived reptile.
• Giant Squid: fastest and largest invertebrate.
• Arctic Tern: longest flying migration.
• Millipede: most legs.

Biodiversity

• 1.25-1.5 million animal species have been described, named.
• There are estimated 2 million and 9 million species of eukaryotes.
• This estimate does not include bacteria or archaea.
• Scientists may be underestimating the total number of species.

Biodiversity Importance

• Biodiversity possesses intrinsic and aesthetic value.
• Biodiversity acts as "insurance".
• Rivet Hypothesis: losing too many species can cause an ecosystem to collapse.
• Ecosystem Productivity and Services: ecosystems have tremendous economic value.
• Replacing ecosystem services would cost tens of trillions of dollars.

Biodiversity Example

• Dr. Terry Erwin fogged trees in Panama's tropical forests.
• Sampled 19 trees of a single species (red oak).
• Found 1,200 beetle species, with 80% undescribed.
• Estimated that 163 beetle species were specific to the host tree (red oak).
• There are roughly 50,000 tree species in the tropics.
• The tropics may contain millions of beetle species.

Biodiversity Hotspots

• Biodiversity hotspots are regions with high concentrations of endemic species facing habitat loss.

Mass Extinctions

• Mass extinctions are defined by the loss of at least 75% of species within a short geological time (around 2 million years).
• The normal rate is ~10% of species lost per million years.
• There is concern we are living through a sixth mass-extinction event.
• Currently, 1 in 4 species are at risk of extinction.
• Habitat loss is a major threat to biodiversity.
• Rising CO2 levels and global warming are contributing factors.

Levels of Complexity

• Nonliving: atoms -> simple molecules -> macromolecules -> membranes -> organelles.
• Living: cells -> tissues -> organs -> organ systems -> animal.

Cell Movement

• Diffusion: molecules move from high to low concentration.
• Osmosis: water diffuses from high to low water concentration.
  • Isotonic: normal
  • Hypertonic: shriveled/dehydrated
  • Hypotonic: swollen/waterlogged
• Filtration: pressure forces solute molecules across a size-selective membrane.
• Active Transport: solutes move against the concentration gradient using carrier proteins and ATP.
• Endocytosis: bulk transport of material into cells.
  • Pinocytosis: cell drinking/non-specific uptake of fluid particles.
  • Phagocytosis: cell eating/ solid material.
• Exocytosis: bulk removal of material out of a cell.

Evolution of Animal Diversity

• Species: a group of interbreeding individuals that share common ancestry and are reproductively isolated.
• Population: a group of organisms of the same species inhabiting a specific geographical area.
• Thomas R. Malthus' principle: there are not enough resources to fully support the reproductive potential of a growing population.
• Charles Darwin developed the theory of natural selection.
  • Perpetual Change: Shown by the fossil record, organisms and their traits change constantly.
  • Common Descent: Groups of organisms share common ancestors.
    • Vertebrate phylogeny is constructed using the fossil record, plus morphological, physiological, and DNA/RNA data.
    • Homology and ontogeny provide evidence for common descent.
    • Homology: similarity in structure or pattern between organisms.
    • Ontogeny: developmental history of an organism.
  • Gradualism: Change occurs gradually over long time periods.
    • Small incremental changes accumulate over long periods to produce large differences in traits characterizing different species.
  • Multiplication of Species (Speciation):. Production of new species.
• Evolution consists of changes in allele frequencies within a population over time.
  • Microevolution: change in allele frequencies within populations over time.
    • Mechanisms: mutation, natural selection, genetic drift, and migration.
• Genetic drift: changes in allele frequencies in a population because of chance events.
  • Especially common in small populations.
  • Natural selection favors heritable traits that enhance survival and reproduction.

Natural Selection

• Natural selection example: peppered moth.
  • Light-colored moths were favored for camouflage, but industrial revolution soot darkened trees, favoring dark-colored moths.
• Adaptations are features that enhance survival and reproduction.
  • They are not a conscious effort by organisms to evolve.
• Sexual selection is a form of natural selection based on mating rituals and physical features.
• Three types of natural selection:
  • Stabilizing Selection: Selects against extreme phenotypes, stabilizing the average.
  • Directional Selection: Phenotypic character shifts in one direction.
  • Disruptive Selection: Selects against average phenotypes, favoring extremes.
• Two situations in which genetic drift can have a significant impact:
  • Bottleneck Effect: population size is reduced due to disturbances (earthquakes, floods, fires, overhunting, habitat conversion), some alleles are lost, which results in reduced genetic diversity..
  • Founder Effect: a small number of individuals colonize a new area. Genetic drift effects are more noticeable in small populations.
• Macroevolution: long term changes in allele frequencies.
• Speciation is new species formation over geological time.
  • Reproductive isolation of populations can occur before mating (prezygotic) or after mating (postzygotic).
• Allopatric Speciation: geographic isolation, exposure to different environments, accumulation of differences via microevolution prevents mating
• Allopatric Speciation is the most common form and can occur due to a vicariance event (an event that isolates species).
• Congo River: an example where 300 species of fish were recently discovered, some within 1 km stretch.
• Romania: mobile cave with a 10% oxygen atmosphere held 48 species, including 33 species unique to Earth. Adaptive Radiation is the production of many species from a common ancestor within a short period of geologic time. Darwin's finches are a classic example.
• Evolution is driven by mutations, genetic drift, and natural selection, leading to speciation and animal diversity.

Animal Ecology

• Animal Ecology studies the relationship and interaction between organisms and their environments.
• It incorporates abiotic and biotic factors, behaviors, physiology, genetics, and evolution.
• Helps us understand geographic distribution, abundance, traits/characteristics, and animal diversity.
• The hierarchy of ecological systems from smallest to largest: organism, population, community, ecosystem, biosphere.
  • Population ranges are limited to ecologically suitable habitats.
• Fundamental Niche: the set of conditions needed for an organism to survive and reproduce; useful for mapping potential occurrences.
• Realized Niche: the actual range a species inhabits after accounting for interactions with other species (competitors, predators, pathogens) , limited by competitors, predators, pathogens, dispersal
• An example states that the Red legged salamander aggressively excludes grey legged salamanders despite overlapping habitats
• Populations vary among species and within population, and are tracked through survivorship curves.
• Age Structure: used to determine if a population is growing, stable, or declining.
• All populations have intrinsic ability to grow exponentially, but limited resources/other extrinsic factors determine carrying capacity (K).
  • Density dependent factors: factors influenced to a variance by crowding (pop size), food supply, temperature, places to live, precipitation, effects of predators, parasites, and diseases.
  • Density independent factors: not varying with degree of crowding.
• Communities are associations of interacting populations within populations (interspecific interaction) between communities (intraspecific interaction)
  • Interactions Can be: Beneficial (+), detrimental (-), neutral (0). -Competition Occurs when there are limited Resources -niche overlap. -A level of competition may determine a level of niche overlap, or a complete niche -> competitive exclusion species.
    • To Co exist in Same habitat, species must partition resources -diff: species specialize diff: resources.
• Biological interaction- Symbiotic relationships -Mutualism - both host of sym-bio benefit e/ clownfish+sea anemone
  • Commensalism-Symbiont benefits + host is unaffected e/g cattle egret and cow -Parasitism-The Parasitc recives benefits at this expense;
    • Horse hair worm, life cylce- larve born in eater.
    • larve eaten by may fly larva.
    • Adults mayfly lives in the water with Parasite inside.
    • May Fly eaten by cricket
    • Predator/prrey
  • 1. the predator recives benefits to the prey,s expense.
  • 2. e/g Rabbit and coyote's
  • Inter-Specific Interaction Shape+ may Anime traits
    • camofloge- Cryptic coloration -Mimicry- Harmless preys mimic harmful preditors -e/g Yello jacket Waso -Mullerian- bot species look alike and are distasteful -A posematic coloration = Advertives Danger
• Potential predators learn bright colors of the prey

Keystone Species

• Keystone species strongly influence a community E/gs
  • The term Ecosystem Refers to Al population of the organisms, that live together in certain area (community)
  • plus this.
  • Energy within the ecosystem-
  • Abiotic -sun autotroph- Heterotrophs
• The ecosystem -Sequence Of energy that transfers the ecosystem -Animal Archetecture-
  • Single Sell
  • Many cells, divisions of labor/cells
  • layered of sells specialization function/ - aggregation Different Issues
  • 5. Organ system ( Most Animal
  • Common artichecteral Themes Bory, Simmetry
    1. Redial
    2. Sessile
    3. Con-Front environment.
       4.Redunduncy of Parts 5. Less complex simmtery
• Bilateral

1. Top+Bot Homals
2. Bilateral Samnetry Line 3 Tipycally, and crocs Section
3. Cellularity

Taxonomy

• Whittaker's 5 Kingdoms -Monera (the prokaryotes)
  • the Eukaryotas is; Portista, planete, frughi & and Malia 1 Characters Trade are used to Dtermine & and relashionships. - characters Masst Have a Gene Basis A. Attribute of Feature that Indicate Relatinedness -Anatomical featuers -Behauios Sequencee of Dha-Recent. Cladograms- Illustates Evvolutionarcy relamship. Synapnorphies -Derived characters Shared Lulushely Evolutionarcy Descendants
• Monophyletic group:Includes all species of Ancental species of Desendents

This quiz covers key ecological concepts such as density-dependent factors, niche overlap, resource partitioning, and carrying capacity. It also explores species interactions and the influence of Malthus's theories on Darwin's natural selection.