In this chapter, the researcher reviewed the opinion of some past and recent writers on the subject and also added their own ideal under the following sub-headings:
- Conceptual frame work
- Theoretical frame work
- Empirical frame work
- Summary

2.1. CONCEPTUAL FRAME WORK
CONCEPT OF ZOOLOGICAL GARDEN

The concept zoological garden is a form of ex – situ conservation, which primarily involves keeping of animals alive outside their natural environment for aesthetic educational researches and recreational purpose (Varadharajan and Pythol 2000). Nigeria is blessed with abundant wildlife species which needs to be properly managed in a sustainable basis to prevent depletion (Opara et –al 2010). Hence the need to adapt strict management of resources, repopulation of endangered species and conservation of wildlife park and zoological garden and management strategies (Ajebede et – al 2010).
Throughout history, human have given value to other species of animals as means of entertainment, education and spirituality in addition to being source of food and clothing (front 2011, 69) collecting and exhibiting and exhibiting animals originated from Ancient Egypt where private collection were reserved for the higher class population as a symbol of wealth and power (wearing and jobberns 2011, 19 – 50). In the 1900’s, zoo’s based themselves as conservation movement, with focus on scientific study of endangered species. In the beginning of the 20th century, zoo became an attraction of mass audiences (Beardworth and Bryan 2001, 88). By the late 1900’s there was a shift in the natural of zoo with public attitude and interest changing nature and conservation, with concern for ecosystem and awareness as they protect endangered species (Wearing and Jobbern 2011, 50.

ROLES OF ZOOLOGICAL GARDEN
(Mason 2011, 189) reveal that the roles of zoo are:
a. Educating people about animals.
b. Conservation of endangered species
c. Safeguarding the welfare visitors
d. To generate revenue
e. Providing visitors facilities such as catering and merchandising
f. Re – introducing captive breeding into the wild and carrying out zoological and veterinary research to improve animal welfare in the wild and in captivity.
On the other hand, zoos served as scientific research, for example, zoologist learn more about animals habit and diseases by studying them in zoos studies of animals living kin zoo, together with examination of those that have died have provide zoologist with information about the structure and function of animal bodies (Usher M.B 2000). Keeping wildlife animals in captivity bring visitors from different parts of the world for different purposes such as to provide sources of recreation in the city, to provide biological specimen to constitutes, a learning resource for secondary school, colleges, and universities. It also provide employment and game reserve, provides sources of protein revenue, esthetics recreation, education and scientific values (Presley 2001). The captive animal propagation is one way of encouraging growth of depleted wildlife species population and so properly planned program of zoo establishment and development is considered as one of effective method for conservation of wildlife (Okpiri 2005). Educational environment study and conservation of the  environment have become a subject of major importance all over the world, not only from the point of view of preventing population, but also from the point of conserving water supplies by protecting water shed, conserving soil, vegetarian and Fauna. (Comphell 2007). Comphell also stated that conservation zoos can provide an important facility for research at both pure and applied levels in both the field and laboratory in colleges and universities. Bigot (2000) emphasized that the primary function of zoo curators is to make visit a leaving experience. The attention and effort given to wildlife conservation and tourism in both state and federal levels have been noted.

CONCEPT OF TOURISM
According to UNWTO 2020 defined as the study of man away from his usual habitat. Activities of a person traveling to and staying in places outside their usual environment for not more than one consecutive year for leisure, business and other purposes, tourism contributes to specie conservation, communities project in developing countries like: Nigeria, environmental education, awareness and economies development (Klutzy, 2000). Filton et al (2000) reported that 20 – 40 percent of international tourism is related to wildlife. In Nigeria, tourism contributed 3.3 percent of total GDP in 2011 with forecast of a 10.8 percent increase for 2012 (WTTC 2012). Smith et al (2012) recognized the role of wildlife tourism as building breeding species management and influencing visitor’s behavior for the benefit of wild animals. Fibs (2007) underscored the value of zoo visitors and their feedbacks for the planning and designing of zoo and more importantly to decision making in zoo management by showing on – going treads. He therefore stands to reason that visitors’ preferences should be seriously considered by policy makers and management of zoo and other similar institutions. An area in which visitors’ preference is highly important for a zoo in particular is choice of animals desired. Woods (2000) observed that humans have definite preference for different species of animals. Knowledge of visitors desires in terms of animals and the features that make the animals appealing will assist zoo management in animal acquisition and also in development of education and interpretation programs listening physical features, behavioral characteristics as factors influencing animals preference (Wood 2000, Wentworth 2012). Wild tourism can be described as tourism undertaken to view and or encounter non – domesticated animals in captive, semi – captive or in their natural environment (CRC 2001, Newsome et al 2005). According to Durbary (2004), it could be non consumptive such as viewing, photographing and fishing.

CONCEPT OF ZOO AND EDUCATION
In zoo and education, a study by Patricia et al 2007 states that conservation and education are key elements in the mission statement of zoos. A survey conducted by the Association of zoo and aquarium (AZA) reveals that the general public rate conservation and education as the most important role of zoo (Frasers and Stickler 2008). Zoo primarily deals with three aspects of conservation practice i.e practice, advocacy and research. Conservation practice entails captive breeding, species rein-introduction programs, species survival plans and the use of zoo revenue for conservation programs in wild. Conservation advocacy include: public engagement, promoting awareness, advocacy, stewarding and fund raising events and schemes, a good example of which is like “Adopt animal scheme at most modern zoos”. Moreover, conservation research is conducted on wildlife biology, population dynamics, animal behavior, health and welfare and there are also publications generated by zoos animals care captivity. The preservation of animals in zoos makes it easier for more people to see them.
As well, zoos have been used to preserve various endangered species. However, zoos have become powerful educational tool for many scholars, biologists and researchers (Falk and Dierking 2000).  Individual who visit a zoo get the rare opportunity to examine the relationship between man and animal (Wagoner and Jenson 2010). Students can learn a lot about certain animals that might not be locally available. Many specimen and animals (Wagner and Jensen 2010) argue that zoo makes it possible for researchers to conduct their studies, for instance, researchers can use caged animals to make various observation about wildlife or animals. The acquired knowledge can be used to support the survival of the wild animals in their natural habitats. It is therefore agreeable that zoos have an important educational role in every society. This because, learning is ever – changing process (Falk and Dierking 2000). In the 1970’s the primary educational target for most American zoo was elementary level children. The idea was that building understanding would lead to appreciation which would eventually produce a generation that was concerned about wildlife and the environment (Wheatly 2000). Wheatly emphasized that although children are still a primary audience, zoos are extending themselves to reach many others audience that can make difference in action today. This initiative includes the membership, governance and employee of zoo.

CONCEPT OF ZOO AND CONSERVATION
In zoo and conservation, according to Max – Planck Gesell Chaft (2011), Zoology garden breeds animal from threatened populations and and thus makes greater contributions towards biodiversity conservation. According to UN (2020) on global biodiversity warned that 1 million species are at risk of extinction with decades, putting the world’s natural life support system in jeopardy. Unfortunately, loss of plants and animals habitat leads to from species extinctions and loss of diversity from ecosystem. Fortunately, not all of the extinctions occur at once. Conservation action may still be able to save threatened species (John M et al 2016). At October 2010, meeting of the Convention on Biological Diversity (CBD) in Nagoya, Japan, delegates discussed a plan to reduce pressure in the planet’s biodiversity. Key targets include expanding coverage of protected areas, halving the rate of loss of natural habitats, and preventing extinction of threatened species. Species whose habitat is severely threatened, however, the outlook is so bleak that the International Union for Conservation of Nature (IUCN), the US Endangered Species Act and the CBD (Article a) recognize that In-Situ conservation action (ie, in the species natural habitat) will need to be combined with Ex-Situ approaches, such as captive breeding in zoos, aquariums and so on (Conde et al 2011).

THE THEORETICAL FRAME WORK
The animal welfare and management (Dakin 2001) is a state of being that can be measured, recognized that its ranges from very poor to very good, introduces the concept of coping, allow measurement separate from moral consideration and refer to feeling as well as physical and psychological health. The definition of welfare that we use also emphasizes that it relates to an individual and thus welfare can differ between different members of the same species, even when exposed to the same condition (Horsey et al 2009). In the case of zoo animals, which have often come from very heterogeneous background, individuals may vary greatly in this previous life experiences and this can influence their ability to cope with certain challenges, by using each animal as its environment and thus an individual’s welfare can be measured.
There are also some species – specific characteristics that have evolved to enable animals cope with different, environment and thus we should also consider welfare at the species level; such species level adaptation could relate to dietary needs, hearing sensitivity, thermo-regulatory needs and so on. The theory of evolution by natural selection, first formulated in Darwin’s book “On the origin of species” in 1859, this theory states Organisms change over time as result of changes in heritable physical or behavioral traits. Changes that allow an organism to better adapt to its environment will help it to survive and have more offspring. The physical and behavioral changes that make natural selection possible happen at the level of DNA and gene, such changes are called Mutation. “Mutations are basically the raw materials on which evolution act. Pobiner said, mutation can be caused by random error in DNA replication or repair, or by chemical of radiation damage. According to Chinaka (2019) in the book concept of evolution, Charles Darwin proposed the concept of natural selection as the mechanism of evolution. The main postulates of Darwinism are:
1. Geometric increase: According to Darwinism, the populations tends to multiply geometrically and the reproductive powers of living organism (biotic potential) are much more than required to maintain their numbers.
2. Limited food and space
3. Struggle for existence
4. Variation etc
Both natural animal populations and those in captivity are subject to evolutionary forces. Evolutionary changes to captive populations may be an important, but poorly understood, factor that can affect the sustainability of these populations. The importance of maintaining the evolutionary integrity of zoo populations especially those that are used for conservation efforts including rein-introductions is critical for the conservation of biodiversity.
Greater appreciation for an evolutionary perspective may offer important insights that can enhance the reproductive success and health examples and associated strategies that highlight this approach, including minimizing domestication (ie genetic adaptation to captivity), integrating natural mating systems into captive breeding protocols, minimizing the effects of translocation on variation in photoperiods and understanding the interplay of parasites and pathogens and inflammation. Captive populations can adapt rapidly to captive environments through demonstration, in which human impose artificial selection in order to increase the prevalence of desired traits in the domesticated population.
For domestic animals, human breeders choose to breed only those individuals that thrive in the captive environments, leading to trans-generational changes that result in a population that is adapted to breed and survive in the conditions imposed by the breeders. Among captive population of animals, zoo populations are unique in that they are maintained to educate the public regarding wildlife and their habitat or to preserve critically endangered species through captive breeding and reinforcement program. Although assessment and preservation of genetic diversity is a top priority for most conservation breeding programs, fundamental to these goals is the maintenance of the genetic variation of these captive populations (Lacy 2009). Whether used to further educational or conservation goals, it is critically that these captive population are representative of the natural populations from which they are desired (Ashley et al 2003). However, maintaining captive population, such that they are reflective of the wild phenotype of the animals, can be challenging in zoos because of the mismatch the environments that the zoo population is originally from and the captive content in which they are been housed. Hendry et al 2015 carol et al 2014, for example, solitary animals with large territories that only encounter sexually mature counterparts during estrus may be housed in proximity of their mate year round, potentially leading to the behavioral issues, including ****** aggregation or ****** incompatibility. Other stressor can exist in captive environments for which animals are not adapted, including the acoustic environments, physical substrate and even availability of food (Morgan and Tromborg 2007). Minimizing the mismatch between the natural environment and the captive environment and they should limit the decline and poor performance of captive populations (Hendry et al 2011; Carrol et al 2014). Captive environments are very different from the wild and can impose different selection pressures that can lead to genetic adaptation in the captivity that affects behaviors (eg: temperaments; MC Douglas et al 2006), morphology (eg; size, skeletal morph metric O’ Regan and Kitchener 2005); and reproductive output (eg; age at ****** maturity, letter size). In particular populations of species with short generation times will adapt more rapidly to captivity than those with long generation time (Frankham 2008).
Social learning theory is the idea that children from observing. According to the learning theory, learning is based on social interaction with the environments (Nwamuo et al 2006). As children walk around the zoo, they are exposed to words and concepts. It also encourages dialogue between parents, siblings, friends and zoo guards (Jessica 2014)  visiting the zoo help the children and other visitors to understand the importance of taking care of the environments as it has a significant impact on lives and welfare of animals and importance of conservation and animal care which will never be forgotten. According to (Nwamuo et al 2006) social learning theory plays a big role in how people and especially learn. There are four elements to social learning theory including:
• Attention: Children can’t learn if they aren’t focused on the task. Students who see something unique or different are more likely to focus on it, helping to learn just as in zoo.
• Retention: people learn by internalizing information later when we can recall that information later when we respond to a situation in the same way which we saw.
• Reproduction: in the way we are able to reproduce our previously learn behavior or knowledge when it’s required. Practicing our response in our head or in action can improve the way we response.
• Motivation

Operant conditioning of behaviors theory of B.F Skinner, enclosure design and environmental enrichment strategies have all been suggested to improve the welfare of zoo animals by reducing stereotypical behavior and rein-introduction success of wildlife species. (WAZA 2015). Thus, the use of these strategies has important consequences for zoological collections. Despite the recognition and wild-scale implementation of such strategies, however, concerns around global zoo animal welfare remain and behavioral pathologies are common in many species. (Luhrs 2010) using operant conditioning, some of the barriers to delivering positive welfare experiences through holistic behavioral management strategies to zoo animals and make recommendations for institutional approaches towards improving zoo animal welfare using examples of Abnormal Repetitive Behaviors (ARBs) through targeted behavioral management.

EMPIRICAL FRAMEWORK
According to P.A Anadu (2000) on his study wildlife conservation in Nigeria: problems and strategy a case study of wildlife reserve of University of Benin, the major treats to nature conservation in Nigeria and he reviewed critically the measures adopted for the protection of wildlife. According the study, the major problem includes habitat degradation (through uncontrolled logging, agricultural projects, industrial plantations, highway and urban development’s and exploitation for fuel wood) over hunting and poaching.
He suggested that to protect wildlife include the creation of more game reserve, enactment of wildlife laws, signing of international treaties and manpower development. According to his research through interview with about 10 workers or staff of the wildlife reserve, the major treats to the area include poaching and hunting, indiscriminate feeling of forest trees, low funding, inadequate game laws and weak enforcement of the existing legal provisions.
It is suggested that the Federal Government should intervene more positively in favor of conservation by creating more national parks and assuming joint responsibility with the states for formulating wildlife laws. Furthermore, the role of nongovernmental organizations in influencing conservation policies and mobilizing public opinion will be cruial in different years ahead.
In the journal “A synopsis of wildlife conservation in Nigeria by Timothy A Afolaya  2009, this article emphasized the recent developments in the overall conservation program in Nigeria as it describes the important role which wildlife is playing in helping to feed the nation, in creating employment opportunities, in education in research, in recreation and in local medicine. Inadequately of Nigerian wildlife legislation and of the trained manpower to protect and manage the wildlife resources are among the crucial wildlife management problems identified. It is also stressed that the basic information for effective management is often lacking where Nigerian wildlife reserved are concerned. It also stressed that the main problems facing wildlife conservation in Nigeria include poaching, over exploitation, lack accurate data, bush burning that destroys wildlife habitat. There is adequate reliable database to facilitate forestry planning and development. Weak forest policy and implementation, forest policies lacks legal backing and hence its enforcement is difficult. The Nigeria forestry policy Act, 1937 is subsumed in the National Agricultural Policy of 1988. Forest tariffs are relatively low and are not revised frequently penalties under most laws are low and seldom enforced. It suggested that Nigeria forestry policy act should be reviewed or renew and encourage the government to implement the policies adequately and enforce penalties on the offenders.
Jonathan (2009) in his own study animal wildlife conservation under multiple land use system in Nigeria reveals that out of 6 selected zoological garden and game reserves in six geopolitical zones in Nigeria. The situation of wildlife in Nigeria is nevertheless different. Except in the Yankari, upper Ogun and Kwiabaha, Game Reserves and the Kainji lake National park, little efforts have been made to protect the Nigerian animal wildlife resources from human pressure and wide spread extinction. To many, what remains of the wildlife animals are best seen in the few state owned zoological gardens in Nigeria?
However, because most indigenous large animal species including Elephant, Buffalo, Chimpanzee, Gorilla, Rhinoceros, Leopard and Ostrich have not been able to reproduce in the various zoological garden so far, the hope to conserve this animals are brittle.
According to his work, animal wildlife is a declining resource in Nigeria because of unplanned land use practices. For example, land uses in game reserves are often conflicting and contradictory for land uses, timber extraction, hunting; food crop production and settlement are simultaneously going on in game reserves with little or no control measures and with no management plans. The excessive demands for land these conflicting uses have greatly disturbed the ecosystems involved, thus making the survival of the wild animals uncertain. Specially, the problems of wildlife conservation in Nigeria are:
a. Poaching
b. Indiscriminate burning of the vegetations
c. Uncontrolled grazing activities in the reserves
d. Intensive logging for domestic and industrial uses
e. Users rights on the reserves enjoyed by the traditional owners of the land before reservation
f. Lack of adequate fund to manage the reserve
g. Ineffective legislation
h. Lack of trained manpower
i. Urban sprawl
j. Infrastructural development of roads, electric and telegram lines and irrigation schemes.
k. Lack of modern enclosure or caging
l. Inability of animals to breed within the captive environment.

He then emphasized that the picture for Nigerian animal wildlife depends on the nation’s ability to conserve what is left either in their natural habitat or at least, in zoological gardens. The game reserve should be reduced to manageable numbers while state governments should win public sympathy through adequate conservation publicity and the provision of sufficient vehicles and personnel to manage the game reserves. The policy of land use in game reserves should be conducted on:
a. The number and species of animals hunted per year
b. The population of animals species in the game reserves and their habitat sustainability
c. The endangered and extinct animals species and specific reasons for the decline in their population
d. Human problems peculiar to each reserve and ways of minimizing them.
e. Establishment of rein-introduction programs.

SUMMARY
The establishment of zoos in a society is premised partly on the idea of bringing man close to wild animal’s species (Yager et al 2015). This establishment has various roles to play in the ecosystem and all endeavors of life. The role of zoological garden as well as wildlife conservation is as follows:
1. Education: zoos are established for the preservation of animal to make it easier for more people to see them and learn their characteristics and habitat. Zoo animals are used for specimens both for secondary schools students and tertiary institution as well as teaching the public the benefit of wildlife. A survey conducted by the Association of Zoos and Aquarium (AZA) reveals that, the general public rate conservation and education as the most important role of zoo (Fraser and Stickler 2008).
2. Conservation: of endangered species to avoid extinction of such animal.
3. Tourism:  it serves as a centre of tourism as people from different parts of the country visit to learn about nature at their leisure.
4. Generating revenue for the government as well as provides employment opportunities individuals etc
Most problems encountered in Nigerian zoos include:
• Poaching
• In availability of breeding species
• Lack of trained personnel’s
• Lack of fund by the Government
• Lack of infrastructure and conservation facilities.