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