ch 53, Invertebrates: Ecdysozoans and Their Characteristics, Ecology and the Biosphere: Species Distribution Factors, Chordates: Key Characteristics and Evolutionary Groups

population ecology

The study of populations in relation to the environment, including environmental influences on population density and distribution, age structure, and variations in population size.

The three Ds of population ecology

density, dispersion, demography

density

density is dynamic, it changes. Birth and immigration increases diversity while death and emigration decreases diversity

Sampling techniques

estimate densities and total population sizes. Estimations: extrapolation (from small samples) and mark and recapture

dispersion

the pattern of spacing among individuals within the boundaries of the population. environmental and social factors influence this

Three types of dispersion

clumped, uniform, random

demography

study of vital statistics of a population and how those statistics change over time. Birth rates- reproductive rates, death rates- survivorship

life table

an age-specific summary of the survival pattern of a population

survivorship curve

Graph showing the number of survivors in different age groups for a particular species.

three types of survivorship curves

Type I: individuals live a long life until an age is reached where the death rate increases rapidly.

Type II: individuals have a death rate that is roughly constant across all ages.

Type III: individuals have a steep downward curve for those of young age that flattens out as they get older.

two growth models

exponential and logistic

exponential growth

Growth pattern in which the individuals in a population reproduce at a constant rate

limits to growth

The argument that both world population and world economy may collapse because available world resources are inadequate.

carrying capacity

Largest number of individuals of a population that a environment can support

limiting factors

Any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms.

logistic growth

Growth pattern in which a population's growth rate slows or stops following a period of exponential growth

Ecdysozoans

Group including Nematodes and Arthropods.

Cuticle

Tough coat that is shed during ecdysis.

Ecdysis

Process of shedding the cuticle.

Nematoda

Phylum of roundworms, ubiquitous in habitats.

Pseudocoelomates

Organisms with a body cavity not fully lined.

Alimentary canal

Digestive tract found in Nematodes.

Detritivores

Organisms that feed on decomposing organic matter.

Heartworm

Parasite affecting dogs, a type of nematode.

Tardigrada

Phylum of water bears, survive extreme conditions.

Omnivores

Organisms that eat both plants and animals.

Arthropoda

Phylum with segmented bodies and jointed appendages.

Exoskeleton

Hard outer structure providing support and protection.

Cephalothorax

Body region combining head and thorax in arthropods.

Tracheal system

Air ducts for gas exchange in terrestrial insects.

Chelicerates

Group with claw-like feeding appendages, includes arachnids.

Myriapods

Group including centipedes and millipedes.

Centipedes

Carnivorous myriapods with one pair of legs/segment.

Millipedes

Herbivorous myriapods with two pairs of legs/segment.

Isopods

Crustaceans like pill bugs, often terrestrial.

Decapods

Crustaceans with ten limbs, including crabs and shrimp.

Echinodermata

Phylum including sea stars and sea cucumbers.

Water vascular system

Hydraulic system for movement in echinoderms.

Chordata

Phylum including vertebrates and some invertebrates.

Deuterostomes

Organisms where anus forms from blastopore.

Ecology

scientific study of the interactions between organisms & the environment

Population

group of individuals of the same species living in an area

Community

group of populations of different species in an area

Ecosystem

the community of organisms in an area and the physical factors with which they interact

Landscape

a mosaic of connected ecosystems

Biosphere

the global ecosystem, the sum of all the planet's ecosystems

Organismal ecology

studies how an organism's structure, physiology, and (for animals) behavior meet environmental challenges

Population ecology

focuses on factors affecting population size & diversity

Community ecology

deals with species interactions in a community

Ecosystem ecology

emphasizes energy flow and chemical cycling among the biotic and abiotic components

Landscape ecology

deals with adjacent ecosystems and how they are arranged in a geographic region

Global ecology

examines the influence of energy and materials on organisms across the biosphere

Dispersal

movement of individuals away from their area of origin

Biogeography

past & present species distribution; a good starting point

Biotic factors

living factors that affect species distribution

Abiotic factors

nonliving factors that affect species distribution

Saguaro cactus distribution

influenced by biotic factors like grazers, pollinators, pathogens and abiotic factors like temperature, moisture & water availability

Transplants

organisms intentionally or accidentally relocated from their original distribution

Invasive species

transplants that negatively impact native species in their new location

Accidental introductions

species introduced unintentionally, often referred to as 'hitchhikers'

Intentional Introductions

species introduced deliberately for purposes such as food, medicine, or landscaping

High reproduction rates

characteristic of invasive species that allows them to proliferate quickly

Chemical warfare (allelopathy)

the production of chemical compounds by plants that can inhibit the growth of other plants

Enemy release

when an invasive species escapes from its natural enemies, allowing it to thrive

Chordate

Animals with a notochord, dorsal nerve cord.

Notochord

Flexible rod providing structural support in chordates.

Dorsal nerve cord

Hollow tube developing into the central nervous system.

Pharyngeal slits

Grooves in pharynx for gas exchange or feeding.

Post-anal tail

Tail extending beyond the anus for balance.

Cephalochordata

Lancelets retaining all chordate characteristics as adults.

Urochordata

Tunicates, marine filter feeders with larval chordate traits.

Vertebrates

Chordates with a backbone and complex structures.

Myxini

Hagfishes, jawless scavengers with rudimentary vertebrae.

Petromyzontida

Lampreys, jawless parasites with cartilaginous skeletons.

Gnathostomes

Jawed vertebrates with enhanced sensory systems.

Osteichthyes

Bony fish with calcium phosphate skeletons.

Chondrichthyes

Cartilaginous fish like sharks and rays.

Ray-finned fish

Most diverse group of bony fish.

Lobe-finned fish

Fish with muscular fins, ancestors to tetrapods.

Tetrapods

Gnathostomes with four limbs for land movement.

Amphibia

Tetrapods requiring water for reproduction and development.

Urodela

Salamanders, amphibians with tails.

Anura

Frogs and toads, amphibians without tails.

Apoda

Caecilians, legless amphibians adapted to burrowing.

Amniotes

Tetrapods with eggs adapted for terrestrial life.

Amniotic egg

Egg with membranes protecting embryo from desiccation.

Reptilia

Reptiles, including lizards and birds, with shelled eggs.

Endothermic

Warm-blooded, using metabolism to regulate body temperature.

Mammalia

Amniotes with mammary glands and hair.

Monotremes

Egg-laying mammals like the platypus.

Marsupials

Mammals with pouch for early developmental stages.

Eutherians

Placental mammals, with prolonged embryonic development.