Ecology concepts

Response to environmental examples

Orienting toward or away from environmental stimuli, navigating over long distances, and possessing a biological clock

Navigation example

Homing pigeons can travel hundreds of kilometers and still return home because they can navigate with star patterns and detect magnetic north

Biological clock example

Some fish and reptiles have specialized cells that detect light and dark

Five types of communication between organisms

Visual, auditory, chemical, tactile, and electrical

Visual communication examples

Differences in color between male and female cardinals, antlers on male deer, bird courtship dances, bright flower colors to attract pollinators

Auditory communication purposes

Warning or impending danger (such as predators) or attracting mates

Chemical communication purposes

Attracting mates, insects communicating a path from a nest to a food source, warning of predators, marking boundaries of territories

Chemical communication in plants examples

Releasing chemicals to warn nearby plants of predators and start production of anti-herbivore chemicals, releasing odors to attract predators

Tactile communication examples

Struggling prey create vibrations in spider webs that alert the spider to their presence, white-lipped frogs press their bodies against the ground when making a mating call to cause a vibration, some insects send vibrations through leaves to communicate with insects of the same species

Electrical communication example

Some fish send weak electrical signals through the water to communicate information

Innate behavior example

Elaborate courtship behaviors in many bird species

Habituation example

Crows are initially scared by a scarecrow, but learn that it is not harmful and continue to eat food from the garden/farm

Connection between responses to the environment and fitness

Learned behaviors lead to fitness

Operant conditioning example

Rats can’t vomit, so they take very small bites when trying new foods and wait to see if they get sick to minimize harm from bad foods while being open to new foods that can improve fitness

Imitation example

Back when milk was delivered to doorsteps in Britain, birds learned that they could peck the foil lid to drink the milk, and this behavior spread to many bird species through observation

Advantages of cooperative behavior

More eyes searching for food and looking out for predators, group defense against predators

Disadvantages of cooperative behavior

Sharing food, higher visibility, higher susceptibility to disease spread

Main method for achieving homeostasis

Negative feedback looks

How ectothermic animals adjust their temperature

Altered behavior

Most plants are [endotherms or ectotherms]

Ectotherms

Plant internal heat regulation example

Skunk cabbage uses its mitochondria to generate lots of heat and energy, giving it the fitness advantage of emerging early in the spring

Effect of net gain in energy

Individual can grow and reproduce and population size increases

Effect of net loss of energy

Individual dies and population declines

Energy and food requirements of endotherms vs ectotherms

Endotherms remain active over a range of environments and therefore have a higher energy requirement and need to eat frequently, whereas ectotherms are more limited in their environment but have lower energy requirements and can go long periods without eating

Energy requirements as body size increases

Larger animals have a lower per-kilogram metabolic rate and lose heat more slowly, therefore they need less energy per kilogram of mass

Plant examples of energy availability determining reproductive strategies

Many plants flower in the spring when more sunlight is available, but others grow during the spring and flower in the fall or even take multiple years to grow before gaining enough energy to flower

Animal example of energy availability determining reproductive strategies

Large mammals breed in the fall so that their offspring are born in the spring, when food is abundant and they have the summer to grow

How much energy a predator gets from its prey

About 10% - the rest is used for life processes

Trophic level with the most biomass

Producers

Limits on the number of trophic levels in a community

Energy available from producers, ecological efficiency

Detrivore example

Earthworm

Decomposer examples

Fungi and bacteria

Release of carbon dioxide into the atmosphere examples

Burning of fossil fuels, volcanic eruptions

How organisms get carbon

Consuming other organisms, because all organisms contain carbon

Source of carbon stored in soil

Decomposition of organisms by decomposers and weathering of rocks and minerals

Forms of carbon in the ocean

Carbon dioxide dissolves into water to create carbonic acid, which dissociates in water to form bicarbonate, which dissociates in water to form carbonate

Most common form of carbon in the ocean

Bicarbonate ions

Determinants of geographic range

Where there are favorable conditions for a species and whether individuals can get there

Determinants of population growth/decline

Number of births vs deaths and immigration vs emigration

Factors that increase population size

Less competition/more resources, more healthy individuals that can reproduce, less predators, immigration

Factors that decrease population size

More competition/less resources, more predators, disease, natural disasters, unusual climate, human activitity, emigration

Organisms with a type I survivorship curve

Humans and other large mammals

Organisms with a type II survivorship curve

Birds and small mammals

Organisms with a type III survivorship curve

Mosquitoes, amphibians, small plants

More diverse community among two with similar species evenness

The community with more species richness

More diverse community among to with similar species richness

The community with more species evenness

Benefit of being a niche generalist

Species can persist as the environment changes over time

Benefit of being a niche specialist

Good if one food source is highly reliable all the time

Niche generalist examples

Gray kangaroo, raccoon

Niche specialist example

Panda

Prey defense adaptation example

The Bombardier beetle has two abdominal glands that attack predators with chemicals, injuring or killing them

Predator adaptation example

Weasels attack porcupines’ faces to kill them and then flip them over to consume the belly and avoid the spines

Parasite living on host example

Ticks, fleas, lice, mites, mistletoe

Parasite living in host example

Tapeworms, fungi, bacteria, viruses

Pathogen example

COVID-19 virus, malaria, common cold, fungi that cause disease in crops

Anti-herbivore defense examples

Spines, distasteful chemicals

Mutualism example

Bees move pollen to help flowers reproduce and flowers give bees food

Commensalism example

Sea anemone protects clownfish from predators and gets nothing in return, but is also not harmed

Keystone species example

Beavers, which build dams to control waterways in an ecosystem

Common types of pioneer species

Moss, lichens, fungus, algae

Time frame for primary succession

Thousands of years

Time frame for secondary succession

Up to 50 years

Causes of genetic diversity at the cellular level

Independent assortment, recombination, mutation

Causes of genetic diversity at the population level

Genetic drift, population bottlenecks, founder effects, natural selection

Benefit of genetic diversity

The population can respond to changing environmental conditions, so at least a portion of it can survive to change and not go extinct

Intentional breeding example

Wild mustard plant has been selected for different stem, leaf, and flower traits, producing cabbage, cauliflower, kohlrabi, and kale, which are all the same species

Unintentional breeding example

Bacteria evolving to become resistant to an antibiotic

Factors that affect species diversity

Habitat size, habitat diversity, keystone species

Characteristics of larger populations

Less susceptible to extinction, more distinct habitats, niches, and species, easier to find and colonize

Keystone species effect on species diversity example

When sea stars are present, there is a lot of species diversity in a marine habitat, but when they’re not, mussels take over

Keystone species effect on ecosystem organization example

In the 18th and 19th centuries, otters were nearly eliminated by hunting. Sea urchin populations increased and kelp nearly disappeared, removing protection of small fish

Effect of species diversity on biomass of producers

As the former increases, the latter increases as well because there are more niches present to be used

Benefits of biodiversity to humans

Economic value, controlling floods, filtering water, taking carbon dioxide out of the atmosphere, providing recreational activities, intrinsic value

Location of highest species richness

Near the equator

Location of lowest species richness

Near the poles

Hypotheses for latitudinal diversity patterns

Tropical habitats are more favorable or are much older and contain species that have evolved and diversified over millions of years

Number of global biodiversity hotspots

36

Result of continental drift and example

Changing climatic conditions and major changes in supported ecosystems; i.e. Antarctica used to be located closer to the equator and was warm and rainy

Description of disruptions caused by ice ages

Glaciers moved south, eliminating existing plants and animals, then receded when temperatures warmed up and ecological succession occured

Description of disruptions caused by mass extinction

Some species go extinct and other new ones evolve, which affects the structure and function of ecosystems

Example or disruption caused by mass extinction

Large herbivores, like the wooly mammoth and saber-toothed cat, went extinct 12,000 years ago, causing increased forestation and plant growth and the extinction of many small mammals

Disruptions caused by meteorological events examples

Forested islands in the Caribbean can be completely destroyed by hurricanes, leaving a more open ecosystem with smaller plants; El Niño changes the direction of wind and ocean surface currents affect precipitation movement, leading to severe droughts

Result of increased human population growth an impact on the environment

Possible 6th mass extinction

HIPPO-C (meaning and what it stands for)

Threats to biodiversity: Habitat loss, invasive species, population growth, pollution, overharvest, climate change

Why invasive species are successful

They can exploit unoccupied niches and abundant resources and usually don’t face predators or competition

Intentional introduction of species example

Honeybees brought to the Americas from Europe to provide a source of honey; brown trout from Europe introduced to other continentss

Unintentional introduction of species example

Brown rats from China spread across Europe during the Industrial Revolution and then to North America on ships

Pollution forms

Oil spills, pesticides, heavy metals, endocrine distuptors

Pollution event example

2010 Gulf of Mexico oil spill: chemical used to break up the oil was toxic and many species, such as sea turtles and dolphins, saw population declines

Overharvesting example

Technology improvements led to a sharp increase of cod fishing in Newfoundland in the 60s and 70s to the point that it had to be stopped in 1992. The lack of cod caused their prey, Jonah’s crabs, to increase their population and eat all the sea urchins

Greenhouse gas examples

Water vapor, carbon dioxide, methane, nitrous oxide

Benefit of greenhouse gases

In their naturally existing levels, they make Earth warm enough to sustain life

Human actions that increase the greenhouse effect

Burning fossil fuels, raising domesticated animals, deforestation, decomposing landfills, production of industrial chemicals

Mean temperature increase of the Earth over the past 140 years

1 degree Celsius

Effects of small temperature changes on biological processes

Timing changes of flowering, bird migration, and animal breeding and whether animal species can survive in warmer temperatures

Solutions to protect or heal habitats from disruption

Harvesting invasive species to reduce their abundance, reintroducing native species, reducing harvesting or overharvested organisms, reducing the concentration of greenhouse gases

Ways to reduce greenhouse gas concentrations

Driving less, taking public transportation more, using energy-efficient appliances and lights, using renewable energy like solar panels and wind turbines