Ecology and Evolution Environmental Ecology PDF

Ecology and Evolution 8/27/24, 1:50 PM Platform | Study Fetch Environmental Ecology (00:00:39 - 00:01:55) Key Terms: Species: A group of organisms that can interbreed to produce viable, fertile offspring Habitat: The plac...

Ecology and Evolution 8/27/24, 1:50 PM Platform | Study Fetch Environmental Ecology (00:00:39 - 00:01:55) Key Terms: Species: A group of organisms that can interbreed to produce viable, fertile offspring Habitat: The place where an organism lives Population: A group of organisms of the same species in a given location Ecological Community: All the populations of different species in a given area Ecosystem: The ecological community and its abiotic factors Abiotic Factors: The non-living elements of an environment (e.g., water, soil) Biotic Factors: The living elements of an environment Biosphere: All the ecosystems on Earth Ecological Factors: Density-Dependent Factors: Factors that depend on population density (e.g., disease, resource competition) Density-Independent Factors: Factors that are independent of population density (e.g., weather, climate) Niche: Realized Niche: The environment where an organism actually lives Fundamental Niche: The range of environmental conditions where an organism can survive Competitive Exclusion Principle: Two species cannot occupy the same niche and maintain population levels; they will compete for limited resources Diagram Example: Shows different bird species foraging at different heights in a forest, demonstrating how they occupy different niches to avoid competition for resources. Biological Interactions (00:04:01 - 00:04:58) Types of Competition: Exploitation Competition: Competition for a common, depleted resource Indirect Competition: Competition for a common, depleted resource Interspecies Competition: Competition between members of the same species for resources Apparent Competition: Competition between two species mediated by a shared predator Types of Biological Interactions (00:05:10 - 00:05:24) Mnemonic for types of competition: Apparent, Exploitation, Interspecies https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 1/7  Symbiosis is an important type of biological interaction to understand 8/27/24, 1:50 PM Platform | Study Fetch Symbiotic Relationships (00:05:24 - 00:05:41) Mutualism: Both species benefit Example: Clownfish and sea anemone Commensalism: One species benefits, the other is unaffected Parasitism: One species benefits, the other is harmed Example: Mosquito or tick Ecosystem Ecology Terminology Food Chains and Food Webs (00:05:54 - 00:06:07) Food Chain: Linear depiction of food interactions Food Web: Interconnected food chains Trophic Levels (00:06:07 - 00:06:37) Autotrophs: Produce their own energy, typically from the sun Heterotrophs: Consume organic compounds for energy Predation: When a predator consumes prey Biomass: Total mass of living organisms in an area Producers, Consumers, and Predators (00:06:37 - 00:07:25) Producers: Primary consumers (e.g., herbivores like cows) Secondary Consumers: Prey on primary consumers Tertiary Consumers: Prey on secondary consumers Apex Predator: Top predator in a given area Energy Flow in Ecosystems (00:07:25 - 00:08:50) Only 10% of energy is converted to organic tissue at each trophic level Energy is lost as heat, waste, and decomposition This limits the biomass at higher trophic levels Decomposers and Scavengers (00:09:04 - 00:09:38) Decomposers: Microorganisms and invertebrates that break down organic material at the molecular level e.g., fungi, bacteria Scavengers: Animals that feed on dead or decaying matter Also called detritivores Scavengers break down large organic material, while decomposers break it down at the molecular level (00:09:38 - 00:10:01) Decomposers are essential for the integrity of the environment Without decomposers, we would be surrounded by undecomposed organic material https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 2/7  Decomposition and Nutrient Cycling 8/27/24, 1:50 PM Platform | Study Fetch (00:10:01 - 00:10:12) During autumn, leaves fall to the ground and accumulate as debris In the spring, the snow melts and the debris is left behind (00:10:12 - 00:10:24) Decomposers break down the fallen leaves during the winter This turns the leaves back into fresh soil Population Ecology (00:10:24 - 00:10:38)Biotic Potential The ability of a species to have the highest possible birth rate and lowest possible death rate This is the maximum population size a species can achieve (00:10:38 - 00:10:50)Carrying Capacity The maximum population size that an environment can sustainably support This is the limit to the biotic potential of a species (00:10:50 - 00:11:03)Population Growth The population will initially grow exponentially, following the biotic potential But it will then level off at the environmental carrying capacity (00:11:03 - 00:11:15) The population growth will be a sinusoidal curve It will reach a threshold based on the carrying capacity (00:11:15 - 00:11:34) The carrying capacity is limited by resources like food, water, and habitat As resources are depleted, the death rate will increase, limiting the population (00:11:34 - 00:11:54) Even if a species can produce many offspring, the population will stabilize at the carrying capacity Excess deaths from lack of resources will balance the high birth rate r/K Selection Theory (00:11:54 - 00:12:07) Different species employ different tactics to produce offspring r-selected species focus on quantity, K-selected species focus on quality (00:12:07 - 00:12:22)K-selected Species Have long gestation periods to produce a few large, robust offspring The offspring take a long time to mature but have a low mortality rate (00:12:22 - 00:12:35)r-selected Species Produce many small offspring that mature quickly Many of the offspring do not survive, but some will reach adulthood https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 3/7 8/27/24, 1:50 PM Platform | Study Fetch (00:12:35 - 00:12:52) r-selected species have a "quantity over quality" approach K-selected species have a "quality over quantity" approach (00:12:52 - 00:13:06)Survival Curves Type I: High percentage of individuals reach maximum lifespan Type II: Constant mortality rate over lifespan Type III: Very few individuals reach maximum lifespan (00:13:06 - 00:13:31) K-selected species have a Type I survival curve with many survivors r-selected species have a Type III curve with few survivors reaching maximum lifespan (00:13:31 - 00:13:54) Catastrophic events are more detrimental to K-selected species, as they have invested heavily in few offspring r-selected species can better withstand losses since they produce many offspring Ecological Succession (00:14:28 - 00:14:42)Ecological Succession The process by which a community develops and changes over time The first species to inhabit an area are called pioneer species (00:14:42 - 00:15:04) There are typically not totally "unfounded" areas, as some life will exist even in newly formed environments The pioneer species begin the process of ecological succession Primary Succession and Secondary Succession (00:15:04 - 00:15:18) Most areas on our planet have had life at some point, even if they are currently uninhabitable like Antarctica or the Arctic These areas can change over time and become re-inhabited Primary Succession (00:15:18 - 00:16:19) Occurs after a large disturbance in an area that has previously not supported life For example, if Antarctica suddenly became very warm Starts with bare rocks and pioneer species Progresses through different stages of succession (lichen, small plants, grasses, shrubs, trees) until it reaches a climax community Climax community is a steady state where ecological succession has achieved a mature, stable ecosystem Secondary Succession (00:16:19 - 00:17:19) https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 4/7  Occurs after a smaller disturbance in an area that has recently supported life 8/27/24, 1:50 PM Platform | Study Fetch For example, a large forest fire Still has a pioneer species and intermediate species, but the process is more rapid Often has some surviving seeds or species that can reestablish more quickly since there is still soil present Keystone Species and Predators (00:17:19 - 00:18:33) Keystone species and keystone predators are critical to maintaining the balance of an ecosystem Example: Sharks are keystone predators that feed on cownose rays If sharks were eliminated, the cownose ray population would explode and decimate other species like bivalves and arthropods This can cause a cascading disruption throughout the entire ecosystem Similar effects were seen when wolf populations were disrupted in the northeastern US, leading to deer overpopulation and coyote invasions Biomes (00:19:07 - 00:19:39) Biomes are areas of land or water defined by their biotic factors, rainfall, and temperature Key terrestrial biomes include: Tropical rainforests Savannas Temperate grasslands Deciduous forests Chaparrals Deserts Taiga Tundra Polar regions Each biome has its own specific temperature and rainfall patterns that define its unique ecosystem Biomes and Ecosystems Tropical Rainforests (00:19:39 - 00:19:57) Unique tropical rainforests have heavy rainfall Very hot and high humidity, allowing for a great diversity of plant species Diverse plant species provide a diverse structure for animals to live in, resulting in a diverse selection of animals Savannas https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 5/7  (00:19:57 - 00:20:24) 8/27/24, 1:50 PM Platform | Study Fetch Hot with very little rainfall Dominated by grasses and some trees Suitable for ungulates (hoofed animals) like giraffes that can move throughout the savanna, graze on the grasses and trees, and find shade Adapted to low amounts of water and rainfall Temperate Grasslands (00:20:24 - 00:20:39) Cool winters, hot summers, and seasonal rain Dominated by grasses and shrubs Many grazing animals thrive in this environment Temperate Deciduous Forests (00:20:39 - 00:21:05) Warm summers, cold winters, and moderate rain Dominated by hardwood trees that shed their leaves in the fall Home to many smaller mammals like birds, rodents, squirrels, porcupines, weasels, and deer Chaparral (00:21:05 - 00:21:32) Hot and dry summers, mild winters Dominated by trees, shrubs, and cacti Home to animals like foxes, deer, and jackrabbits Deserts (00:21:32 - 00:21:57) Hot days, cold nights, very little rain Mainly home to cacti, reptiles, arachnids, and coyotes Hard to support a large biomass due to the harsh conditions Taiga (Coniferous Forests) (00:21:57 - 00:22:13) Cold winters with snowfall, warm rainy summers Dominated by coniferous trees Home to larger mammalian species like bears, otters, and wolves, as well as smaller mammals Tundra (00:22:13 - 00:22:26) https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 6/7  Cold with little precipitation 8/27/24, 1:50 PM Platform | Study Fetch Dominated by mosses and shrubs Home to bears, wolves, caribou, and reindeer Polar Regions (00:22:39 - 00:22:57) Cold, snowy weather, mostly ice, very little plant life Home to penguins and polar bears Aquatic Biomes (00:23:14 - 00:23:26) Saltwater biome is the largest on Earth Freshwater biome has less than 0.1% salt content Aquatic Ecosystem Zones (00:23:26 - 00:23:52) Euphotic Zone: Closest to the surface, with good light penetration Littoral Zone: Part of the euphotic zone where sunlight reaches the bottom Dysphotic Zone: Semi-radiated, not enough light for plants to survive Aphotic Zone: No light, few if any species can survive (deep ocean) https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce11dab844ddbfdeba1989/document?newNote=true&go=note 7/7